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| mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 1 rev 1.0 21-july-2001 3901090313 features and benefits dual low noise, low offset, fully programmable amplifier chain 12 bit on-chip adc powerful signal conditioning and linearisation unit multiple output options: 12 bit digital through spi, 8 bit resolution analog linear signal outputs or 10 bit pwm, both for ambient and object temperature. on-chip programmable digital moving average lpf for ultimate low noise performance isp i/o-configuration and analog settings, accessible by spi serial interface. wide supply voltage range from 4.5v-80v applications thermopile + thermistor amplification chain digital or analog, linear, ambient-compensated ir sensor interface general purpose programmable sensor amplifier/ signal conditioner ordering information part no. temperature suffix package temperature range mlx90313 k df -40c to 125c automotive functional diagram description the mlx90313 is a versatile in-circuit programmable interface, which performs signal conditioning, linearisation and ambient temperature compensation, particularly for infrared sensors combined with a thermistor. other types of sensors can also be used in various configurations. sensors that can be used include pressure sensors, strain gauges, acceleration sensors etc. the amplifier chains in mlx90313 are programmable in very broad ranges of gain. both chains consist of high performance, chopper-stabilized amplifiers, providing excellent noise performance and low offset. the i/o configuration as well as analog settings are in- circuit programmable by means of the spi-serial interface. this serial link can also be used to read out the output signals digitally. the circuit can either provide linear analog or pwm (pulse width modulated) signal outputs. additional the circuit can perform simple control applications using on-board comparators pga pga a/d 12bit a/d 12bit linearisation unit pwm lin output option selector non lin pwm lin non lin configuration eeprom digital control logic spi interface ir path thermistor path ir+ tinp tinn irout tempout ir- spi interface supply regulator
mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 2 rev 1.0 21-july-2001 3901090313 mlx90313 electrical specifications dc operating parameters t a = -40 o c to 125 o c, v dd = 4.5v to 80v (unless otherwise specified) parameter symbol test conditions min typ max unit regulator and consumption supply voltage range vin1 vdd1 7 80 v supply voltage range vin vdd 4.5 5 5.5 v supply current idd @ ta=25 c 55.6ma regulated supply voltage vreg vdd, 10uf ext. cap 4.7 5 5.3 v regulated voltage temperature coefficient tcvr -2.35 mv/ por threshold voltage vpor 1.1 1.3 1.5 v band-gap reference analog ground voltage agnd 2.3 2.5 2.7 v analog ground thermal coefficient tcbg 15 50 v/ reference current mirror load drive voltage vcref 1.8 2 2.2 v ir-chain amplifier and output driver common mode input range cmir -0.1 vdd-3 v common mode rejection ratio cmrr f 100khz rsens < 60k ? * 75 db power supply rejection ratio pssr f 100khz 75 db available gain settings air 55 5500 v/v gain tolerance gir -6.5 +6.5 % amplifier offset voff 4 v input referred white noise vnir rms-value 25 nv/ hz chopper frequency fc 8 khz output voltage range irout 0 vdd- 0.2 v output source current iod irout 1 ma output sink current ios irout 20 a dc output impedance, drive rod irout 10 ? dc output impedance, sink ros irout 100 ? capacitive load irout pin cmax irout 50 pf amplifier bandwidth bw 500 hz temp-chain amplifier and output driver common mode input range cmir 0.1 vdd- 3v v common mode rejection ratio cmrr f 100khz 75 db power supply rejection ratio pssr f 100khz 75 db tinp bias current itpb bias current enabled 1/7 .1 icref* available gain settings atemp 1 40 v/v mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 3 rev 1.0 21-july-2001 3901090313 parameter symbol test conditions min typ max unit gain tolerance gtemp bias current enabled -6.5 +6.5 % amplifier offset voff 4 v input referred white noise vntemp rms-value 400 nv/ hz chopper frequency fc 8 khz output voltage range ortemp tempout 0 vdd- 0.2 v output source current iod tempout 1 ma output sink current ios tempout 20 ua dc output impedance, drive rod tempout 10 ? dc output impedance, sink ros tempout 100 ? capacitive load tempout pin cmax tempout 50 pf amplifier bandwidth bw 500 hz rel1 open drain relay driver high voltage protection 32 v output impedance ro 10 ? comp1 comparator potentiometer input range irirout irout 0 100 % of vrefp adc input stage gain 2.95 3 3.05 v/v external reference voltage vrefpex 1 3.3 v internal reference voltage vrefp 2.4 2.5 2.6 v vrefp input leakage current ilvrefp @150 c 5ua resolution 12 bit monotonicity guaranteed by design differential non-linearity dnl 0.4 lsb integral non-linearity inl ? lsb gain error full scale 1 lsb total input-referred noise vref=3v 0.2 lsb dac resolution 8 bit monotonicity guaranteed by design differential non-linearity dnl ? lsb integral non-linearity inl ? lsb *rsens is the impedance of the sensor connected between irinp and irinn for the ir-chain amplifier. **icref is the current flowing out of pin cref mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 4 rev 1.0 21-july-2001 3901090313 general description the mlx90313 is a versatile in-circuit programmable interface, which performs signal conditioning, linearisation and ambient temperature compensation, particularly for infrared sensors combined with a thermistor. other types of sensors can also be used in various configurations. sensors that can be used include pressure sensors, strain gauges, acceleration sensors etc. the amplifier chains in mlx90313 are programmable in very broad ranges of gain, between 50 and 12000 for the ir-chain and between 1 and 120 for the temp-chain. both chains consist of high performance, chopper-stabilized amplifiers, providing excellent noise performance and low offset. the i/o configuration as well as analog settings are in-circuit programmable by means of the spi-serial interface. this serial link can also be used to read out the output signals digitally. the circuit can either provide linear analog or pwm (pulse width modulated) signal outputs, relative to an analog ground, or several combinations of analog and digital comparator driven outputs. two comparators controlled by either one of the two linearised signals are available on chip with different possibilities for the threshold level, polarity and switching hysteresis. one of the comparators drives the open drain output. the user can provide the threshold for this comparator at the irout i/o pin with a simple potentiometer. a bias current for the thermistor can be obtained at the tinp input by connecting an external resistor between the cref pin and vss. the standard package is soic-20. unique features the mlx90313 integrates dual low noise programmable gain amplifier stages. both thermistor and ir signal path can be configured to suit a large number of components and applications. the onboard analog to digital converter (adc) combined with the digital linearisation unit results in linear output signals. these output signals are available as analog or digital output signal. applications requiring digital temperature information can use single wire pwm output or spi serial communication. the complete configuration and calibration is in-system programmable through the spi interface. combination of all these integrated features combined with a thermopile sensor make the mlx90313 a true high accuracy automotive grade single-chip infrared thermometer. absolute maximum ratings supply voltage, v in1 (overvoltage) 80v supply voltage, v in (overvoltage) 6v supply voltage, v in1 (operating) 16v supply voltage, v in (operating) 5.5v reverse voltage protection -5v supply current, i dd 5.6 ma output current, i out 3 ma operating temperature range, t a -40c to +125c operating temperature range, t s -55c to +150c esd susceptibility 2 kv rel1 output impedance 10 ohms mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 5 rev 1.0 21-july-2001 3901090313 pin-out 1 2 3 4 5 6 7 8 9 10 11 12 20 19 18 17 16 15 14 13 tinp tinn irinp irinn vss rel1 irout sdin tout1 tout2 cref vrefp agnd vdd1 vdd tstclk sclk sdout csb tempout pin symbol description 1 tinp temp-chain amplifier positive input 2 tinn temp-chain amplifier negative input 3 irinp ir-chain amplifier positive input 4 irinn ir-chain amplifier negative input 5 vss supply pin 6 rel1 open-drain relay driver output 7 irout ir-chain amplifier output 8 sdin spi data input 9 tout1 test pin/ oscillator output 10 tout2 test pin, leave open 11 cref bias current reference 12 vrefp reference voltage input/output 13 agnd analog ground, band-gap reference voltage 14 vdd1 automotive ignition supply pin 15 vdd regulated supply pin 16 tstclk clock for test mode; leave open 17 sclk spi clock input 18 sdout spi data output 19 csb spi chip select active low 20 tempout temp-chain amplifier output mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 6 rev 1.0 21-july-2001 3901090313 pin descriptions tinp temperature sensor positive input pin. the pin connects to the temp-chain amplifier and the on-chip biasing current source. the source is a mirrored version of the current running into cref with programmable ratio. the current source can be switched off for use of external current biasing. tinn temperature sensor negative input. irinp - irinn thermopile sensor input pins. vss: supply pin rel1 open drain relay driver output. the typical on-resistance of this driver is <10 ? with a supply voltage of vdd=5v. different configurations are possible as shown below. comp rel1 tambient or tobject threshold in eeprom hysteresis in eeprom vss comp rel1 tambient or tobject hysteresis in eeprom irout vss vss vrefp external potentiometer the comparator is a 12 bit digital comparator. the input polarity can be inverted or not. the threshold and hysteresis registers are 16 bit registers of which the 11 msbs are used in the comparator circuitry. the voltage on the irout pin is sampled with 8 bit adc referred between vrefp and vss pins. note. in case of potentiometer use the linearised analog output is not available. in this case the dac is used as 8-bit adc for potentiometer (or other voltage source) monitoring. irout irout/potin analog/digital i/o pin. this pin can be configured as analog output of the ir sensor or as input for an external potentiometer. (see pin description of rel1). as analog output, this pin can either be connected to the analog amplified ir sensor signal or to the linearised object temperature by means of the dac. the driver can source at least 1ma and sink at least 20 a to/from an external load. if the capacitive load on this pin exceeds 50pf, this load should be de-coupled by means of a series resistor. this pin can be configured also as digital output to transmit the ir temperature in pwm format. the pin is protected for over-voltage and can withstand 16v. sdin serial data input pin for the spi. data is accepted on the rising edge of the serial data clock (sclk) sdout mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 7 rev 1.0 21-july-2001 3901090313 serial data output pin for the spi. data is valid on the rising edge of the serial data clock (sclk) sclk serial data clock from the external master to be supplied to this pin. maximum frequency = 125khz. csb active low, chip select pin for the spi. communication is started on the falling edge of cs and ended on the rising edge of cs. tout1 - tout2: test pins. in normal mode, the internal clock signal of 1mhz is present on tout1 and the clock of the chopper amplifier is present on tout2. cref current reference output. cref is the reference voltage output for the temperature independent current source. the requirements for the resistor to be connected between cref and vss depend on the required accuracy and range of the ambient temperature measurement. the voltage level at cref depends directly on the internal band-gap. vrefp voltage reference i/o pin. this level is by default dependent on the on-chip band-gap reference source and can be programmed in range 2-4.5v from eeprom . this voltage is used as reference for the dac, external applied potentiometer and 8-bit adc. the chip can be configured to use an external reference voltage instead of the on-chip reference. the pin is protected from over-voltage and can withstand 16v agnd analog ground reference pin. this voltage is derived from the on-chip band-gap and has a typical level of 2.5v for maximum output range of the amplifiers. when irout and/or tempout are connected directly to the amplified analog signals, then these signals are referred to agnd. the regulator can be stopped from the eeprom configuration register. in this case the pin can be used for external reference for the 12- bit adc. the pin is protected from over voltage and can withstand 16v vdd1 high voltage supply pin. this supply pin can be connected directly to an automotive ignition supply voltage. the internal regulator can operate with voltages between 7v and 80v. vdd 5v regulated supply pin. the 5v regulated voltage from the on-chip regulator is available on this pin. the internal regulator can supply up to 20ma to external circuitry. vdd can also be used to supply the chip directly with an external 5v regulated supply. tempout tempout analog output/comparator output pin. this pin can be configured as analog output of the mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 8 rev 1.0 21-july-2001 3901090313 temperature sensor or as output of the internal comparator circuit. as analog output, this pin can either be connected to the analog amplified temperature sensor signal or to the linearised ambient temperature by means of the dac. when used as comparator output, different configurations are possible as shown below. comp tambient or tobject threshold in eeprom hysteresis in eeprom analog options tempout the driver can source at least 1ma and sink at least 20 a to an external load. if the capacitive load on this pin exceeds 50pf, the load should be de-coupled by means of a series resistor. the pin is also output for linearised tambient in pwm mode. the pin is protected from over-voltage and can withstand 16v mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 9 rev 1.0 21-july-2001 3901090313 analog section supply regulator and power-on reset the on-chip supply regulator and can be powered by an automotive ignition supply line (7v-80v). the chip can withstand sae standard ignition transients. the resulting voltage of the regulator is available on vdd (5v 300mv). the vdd pin can source up to 20ma to external circuitry. the chip can also be supplied directly with a 5v regulated supply on pin vdd. the power-on reset (por) circuitry is completely internal. the chip is fully operational 16ms from the time the supply crosses 1.3v. the por circuit will issue another por if the supply voltage goes below 1.3v. band-gap, dac and adc references the on-chip trimmable, curvature compensated band-gap circuitry provides a stable reference level (less than 10ppm per c) for several derived reference potentials used for normal operation in mlx90313. the analog ground at the agnd pin is directly derived from this band-gap voltage. the output voltages from both amplifier chains are relative to this potential. the agnd reference can be trimmed internally to (2.5v 20mv). the regulator at agnd pin can be switched off to minimize the current consumption. the pin can be also used as external input for the internal 12-bit adc. the reference voltages for adc and dac are also derived from the band-gap. the dac reference is available at pin vrefp. the mlx90313 dac reference voltage can be programmed on chip to one of the following values: 2, 2.5, 3, 3.5, 4 and 4.5 v. depending on the customer application melexis can program the linearised analog outputs for object and ambient temperatures providing absolute voltage/temperature dependence. the internal regulator for the dac reference voltage can be switched off to minimize the consumption (if linearised analog output is not in use) or to use externally supplied reference for dac reference in range 2 to 5v the adc reference is 2.5v typically. the chip can be also programmed to use external adc reference connected to pin agnd. the current reference bias voltage (present at cref pin) is also derived from the on-chip band-gap reference. ir-amplifier chain mlx90313 is available with gain settings for the ir-amplifier chain ranging from 55 to 5500. the gain can be selected by setting the appropriate bits of the ?irgain1?-register (eeprom address 00h) according to the table below. any gain between the abovementioned limits can be obtained within an accuracy of 6.5%. the amplifier input-referred white noise level is below 23nvrms/ hz. in the application with ir- sensors, with output resistance of 50k ? typical, the total system noise will however depend mainly on the noise of the sensor and will rise up to 45nvrms/ hz. the offset for the chopper stabilized amplifier path can be largely calibrated out and amounts to maximum 4 v. the common mode input range of the amplifier is ?100mv to vdd - 3v. the output range of the amplifier is 0v to vdd-0.2v. the output of the amplifier is referred to the potential on agnd. ir chain gain settings l pa b pr ir g g g g g = stage pr g b g pa g l g contr. bits gci0 gci3 gci2 gci1 gci4 gci7 gci6 gci5 0xx5 0001.067 10010 0011.143 10115 0101.231 010 11020 01 0111.333 1001.455 1011.600 1101.778 setting 120*1112515 1112.000 mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 10 rev 1.0 21-july-2001 3901090313 * this option is available only if enln=1 the pin enln controls both the noise level and distortion of the amplifier. if enln=1 the noise of the amplifier is 23nvrms/ hz, the gain of 20 in first stage is available but the input signal must be less than 4 mv for less than 0.05% full scale distortion. if enln is 0 then the span of the input signal can be 40mv with distortion less than 0.1% full scale. in this case the noise floor of the amplification chain increases 3 times. temp-amplifier chain mlx90313 is available with gain settings for the temp-amplifier ranging from 5 to 50. the gain can be selected by setting the appropriate bits of the ?temp gain and current control?-register (eeprom address 02h) according to the table below. any gain between the abovementioned limits can be obtained within an accuracy of 6.5%. it is also possible to completely bypass the temperature amplifier and force the input signal directly to the adc. the amplifier input-referred white noise level is below 400nvrms/ hz. the common mode input range of the amplifier is ?100mv to vdd-3v. the output range of the amplifier is 0v to vdd-0.2v. the output of the amplifier is referred to the potential on agnd. temp chain gain settings m g g g l pr t = stage pr g l g m contr. bits gct2 gct1 gct0 gct5 gct4 gct3 irsel2 irsel1 irsel0 0001xxx 0001.067000off 0115 0011.1430011/7 100100101.2310102/7 101150111.3330113/7 1001.4551004/7 11020 1011.6001015/7 1101.7781106/7 settin g 11125 1112.0001111 note: when the current mirror is on (all settings except irsel[2:0] = 000b) the gain is defined as follows: icref rsens vout g t ? = where vout is the output of the analog amplifier chain, rsens is the resistance of the sensor connected between tinp and tinn and icref is the current out of cref. when the current mirror is off (irsel[2:0]=000b), m should be replaced by 1 and the gain is defined as follows: vin vout g t = where vin is the voltage difference between tinp and tinn if gct[2:0]=0 then the temp chain will be completely off, the timp pin will be connected directly to the adc input, providing gain=1 current reference the thermistor (or sensor) connected to tinp must be biased with a current source. this bias current is mirrored from the current through the external resistor between cref and vss. the voltage maintained at the cref pin is derived from internal band-gap voltage, and thus constant. the typical value of the voltage at cref pin is 2v. the current mirror ratio can be set between 1/7 and 1 according to the table for the temp-chain gain settings. the setting with irsel[2:0]=000b switches the current mirror off. in this case the thermistor must be biased by external circuitry. mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 11 rev 1.0 21-july-2001 3901090313 analog-to-digital converter (adc) mlx90313 contains a 12-bit internal analog to digital converter. real 12 bit conversion is achieved by a fully differential signal path of the converter. the input amplifier of the adc has a fixed gain of 3. automatic calibration is implemented in the background, which allows precise conversion in a very wide temperature range. the adc sampling rate is 7k samples/second. the reference voltage for the adc is normally a scaled version of the internal band-gap reference and is fixed to be 2.5v. alternatively mlx90313 can be configured to work with an external reference potential applied to the agnd pin. in this case the appropriate bit in the configuration register (seladref bit in confreg1) must be cleared. internal adc can work with references down to 1 v keeping the 12-bit resolution. the adc contains an interface circuit to scale and offset the analog signals in order to make the most efficient use of the available resolution. after amplification the ir and temp sensor signals are referred to agnd voltage level (typical value 2.5v). the additional offset is scaled version of the agnd. the adc interface circuit is given below. the output of the temp-chain is amplified relative to the voltage reference vreft, which can be controlled with 2 bits (bit10 and bit9, eeprom address 02h). the possible values for vreft can be calculated according to the equation : 70 ) 63 ( 4 . 1 k vagnd vreft + = , where k =0 to 3, corresponding to the value of the control bits. the typical values are 3.15, 3.20, 3.25 and 3.3v. if the temp path amplifier is bypassed then vreft will be fixed to: agnd x 0.28 = 0.7v typical. the output of the ir-chain is amplified relative to refir and can be calculated according to the following equation: 70 ) 34 ( 4 . 1 k vagnd vrefir + = , where k=0:31 depending on the selected value of rsel[4:0] the typical values (for agnd=2.5v) are listed in the table below: adc interface setting rsel[4:0] refir [v] rsel[4:0] refir [v] rsel[4:0] refir [v] rsel[4:0] refir [v] 11111b 3.25 10111b 2.85 01111b 2.45 00111b 2.05 11110b 3.20 10110b 2.80 01110b 2.40 00110b 2.00 11101b 3.15 10101b 2.75 01101b 2.35 00101b 1.95 11100b 3.10 10100b 2.70 01100b 2.30 00100b 1.90 11011b 3.05 10011b 2.65 01011b 2.25 00011b 1.85 11010b 3.00 10010b 2.60 01010b 2.20 00010b 1.80 11001b 2.95 10001b 2.55 01001b 2.15 00001b 1.75 11000b 2.90 10000b 2.50 01000b 2.10 00000b 1.70 mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 12 rev 1.0 21-july-2001 3901090313 x3 adc adc x3 ir-chain out temp-chain out vreft vrefir linearisation unit irgain register: [rsel4:rsel0] tinp pin tinn pin config register 1: byptemp vrefp vrefp -vrefp -vrefp 12 12 adc reference configuration digital-to-analog converter (dac) a 8 bit digital to analog converter can be used to output the data for the linearised tobject- and tambient signals. the dac can work with a internal programmable reference voltage, as well as with an external one. in case the internal reference voltage is used, this voltage can be monitored on the vrefp pin. if one wants to use his own reference voltage, this can be done by applying this voltage to the vrefp pin, and setting the appropriate configuration bit. the result from d/a conversion is stored on hold capacitors and buffered. the signals are available at irout and tempout respectively, if the appropriate bits are set in the configuration register (eeprom address 04h). the reference value for the d/a can be programmed with 3 bits: seldr[2:0] (register irgain2) according to the table below: seldr2 seldr1 seldr0 endrefdiv vrefp 00002 00102.5 01003 01113.5 10014 10114.5 for reference voltages higher than 3v the endrefdiv bit must be set. in this case the asic will divide internally the reference by 2 to provide proper input common mode for the output buffer amplifiers at pins irout and tempout. in this case the result of the d/a conversion result will be amplified times 2 by the output amplifiers, which will ensure the requested signal swing. melexis can rescale the dac reference and eeprom table for the linearisation unit to provide absolute analog output. this way, at maximum calibrated temperature, the voltage of irout or tempout pin will always correspond to the requested d/a reference voltage. the regulator for the vrefp voltage can be stopped and an external reference voltage can be forced and used from the d/a. the regulator for dac reference voltage can also be stopped (bit endacref=0) when dac is not in use. this will save some supply current. mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 13 rev 1.0 21-july-2001 3901090313 agnd dac irout tout dacref endrefdiv endrefdiv seldr(2:0) vrefp irout, tout dac configuration output drivers the irout and tempout outputs can be connected to various signals available: the amplified analog signals (irinp-irinn and tinp-tinn), the linearised object respectively ambient temperature signals, or to the comparator circuitry. the irout and tempout pin drivers can source 1ma and sink 20 a and are reverse voltage protected down to ?5v relative to vss. the available configurations are described in table below. input/output setting i/o pin irout tempout control bits iroutc[1:0] configuration toutc[1:0] configuration 00b ir-chain out 00b temp-chain out 01b linear tobject 01b linear tambient 10b threshold rel1 input 10b comp1 out setting 11b pwm out 11b pwm out rel1 is an open drain relay driver output controlled by the on-chip comparator circuitry. the available configurations are described in the section on the comparator circuitry. mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 14 rev 1.0 21-july-2001 3901090313 digital section the digital unit on board of mlx90313 realizes all functions for control, configuration, measurements and linearisation. it contains several registers, alu and control logic. all functions of the asic are hardware fixed and controlled by different state machines, which execute in sequence all procedures necessary for normal chip operation. internal registers overview the table below contains all internal registers, their addresses for access via spi serial interface and short functional description. depending on their function they can be divided in 3 groups: ? control registers: they keep the configuration of the chip including all gain settings of the amplifiers, analog ground level, band-gap and oscillator trimming data, etc. all this data is stored in eeprom and after por the system loads it in the corresponding peripheral registers. ? data registers: they keep all data for offsets, results from measurements and linearisation of both chains. this registers can be read vis spi in normal mode and are write accessible during test mode. ? computation registers. these registers support the computation unit and keep all temporary data necessary for digital low pas filtering, linearisation and comparator functions. they are not accessible via spi in normal mode. internal register table. address access via spi register function dec hex write read irgain1 ir-chain settings 0 00h test mode no irgain2 ir-chain settings 1 01h test mode no tempgain temp-chain settings 2 02h test mode no confreg1 configuration 3 03h test mode always confreg2 configuration 4 04h test mode always oscillator oscillator 5 05h test mode no bgcontrol bandgap control 6 06h test mode no lpf low pass filter 7 07h test mode no adcreg adc output data 8 08h test mode always irout tobject (lin) 9 09h test mode always tout tambient (lin) 10 0ah test mode always irdata ir-chain output 11 0bh test mode always tdata temp-chain output 12 0ch test mode always iros ir-chain offset 13 0dh test mode always tos temp-chain offset 14 0eh test mode always mainstm main state machine 15 0fh test mode no test test mode control 16 10h always no reg temp temporary register for test test mode no reg a accumulator a test mode no reg b accumulator b test mode no testctrl 1 test control 20 14h test mode no reg c accumulator c test mode no reg e accumulator e testmode no testctrl 2 adc test control 23 17h test mode no wp eeprom write protect 24- 31 18h- 1fh always no mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 15 rev 1.0 21-july-2001 3901090313 configuration and control registers overview and bit functions as they are read from the module bit functions registerh b15 b14 b13 b12 b11 b10 b9 b8 registerlb7b6b5b4b3b2b1b0 irgain1h endrefdiv endac enln gci7 gci6 gci5 gci4 gci3 irgain1l gci2 gci1 gci0 irgain2h agndc3 agndc2 agndc1 agndc0 seldr2 seldr1 seldr0 rsel3 irgain2l rsel2 rsel1 rsel0 tempgainh trsel1 trsel0 irsel2 irsel1 irsel0 gct5 gct4 gct3 tempgainl gct2 gct1 gct0 confreg1h error envr hvsup seladref potmet comp1v comp1p byptemp confreg1l rel1v rel1p eewren testmode confreg0h iroutc1 iroutc0 toutc1 toutc0 subinc subdec ntc timeos3 confreg0l timeos2 timeos1 timeos0 osch enagndb oscl bgh bgl lpfh rsel4 enosm entav iros tos lpfir2 lpfir1 lpfir0 lpfl lpft2 lpft1 lpft0 testh1011001 testl testctrl1h testctrl1l testctrl 2h testctrl 2l wph wpl 1100101 register descriptions irgain1 read access: no. the data is accessible for read via spi only from eeprom address 00h. write access: directly to the register in test mode. to eeprom if wp-register is correctly set. irgain1 bit functions name por val function endrefdiv x 1 divide the reference for the dac and enable output amplification by 2 of the to and ta outputs. must be set for vref=3.5v,4v,4.5v. endac x 1 enable the dac regulator enlin x 1 enable low noise. gci[7:0] x 00000000- 11111111 control the gain of the ir amplifier chain (see ?ir amplifier chain?) irgain2 read access: no. the data is accessible for read via spi only from eeprom address 01h. write access: directly to internal register in test mode. to eeprom if wp-register is correctly set. irgain2 bit functions bit por val function agndc [3:0] x 0000-1111 reserved seldr [2:0] x adjustment of the dac reference. x 000 vref = 2v x 001 vref =2.5v x 010 vref = 3v x 011 vref = 3.5v mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 16 rev 1.0 21-july-2001 3901090313 irgain2 bit functions bit por val function x 100 vref = 4v x 101 vref = 4.5v rsel[3:0] x 0000-1111 select the value of the analog ground for ir signal path.the bits are 5, rsel4 is in lpf register (see ?adc? part) tempgain read access: no. the data is accessible for read via spi only from eeprom address 02h. write access: directly to internal register in test mode. to eeprom if wp-register is correctly set. tempgain bit functions bit por val function trsel[1:0] x 00-11 reference voltage for tambient measurement at adc interface input. irsel[2:0] x 000-111 current mirror ratio: see under m in table ?temp chain gain settings? in the section on the temp-amplifier chain (analog features) gct[5:0] x 000000- 111111 temp-gain: see table ?temp-chain gain settings? in the section on the temp-amplifier chain (analog features) confreg1 read access: directly from internal registers or eeprom. write access: directly to internal register in test mode. to eeprom if wp-register is correctly set. confreg1 bit functions bit por val function fatal error x 1 flags multiple eeprom failure. hamming coding can detect and correct only one bit per address. bit will be cleared when going in test mode,disabling eeprom protection and returning in normal mode.( for diagnostics only) envr x 1 stops the internal reference for dac (pin vref). the reference voltage can be supplied externally. if endac=0 then vref is input. hvsup 1 1 enable the regulator for battery supply. note!!! after por this regulator will be always on. it can be stopped from eeprom data. 0 external supply of adc reference to agnd pin. seladref x 1 enable the internal adc reference (connected to agnd pin). 0 sets threshold level for rel1 to threl1 in eeprom (address 75h) potmet x 1 sets potentiometer input (pin irout) as threshold level 0 sets tobject as target voltage for comparator comp1 comp1v x 1 sets tambient as target voltage for comparator comp1 0 sets polarity of comp1: inverting comp1p x 1 sets polarity of comp1: non-inverting 0 output of temp amplifier path is connected to adc byptemp x 1 connects tinp-tinn directly to the adc, bypassing the temp-chain 0 sets tobject as target voltage for rel1 rel1v x 1 sets tambient as target voltage for rel1 0 sets polarity of rel1: inverting rel1p x 1 sets polarity of rel1: non-inverting eewren 0 1 enables write access in eeprom *write protect testmode 0 1 indicates chip is in test mode *write protect *control bits eewren and testmode are write protected. their values can be set only with writing the appropriate data in ?test? and ?wp? registers. these bits are flags which indicate the system operation mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 17 rev 1.0 21-july-2001 3901090313 mode. confreg0 confreg0 bit functions bit por val function 00b irout pin function: ir-chain out 01b irout pin function: linear tobject 10b irout pin function: threshold rel1 input iroutc[1:0] 11b irout pin function: pwm out 00b tempout pin function: temp-chain out 01b tempout pin function: linear tambient 10b tempout pin function: comp1 out toutc[1.0] 11b tempout pin function: pwm out 0 2nd order derivative of thermistor function is positive (used if ntc=0) subinc 1 2nd order derivative of thermistor function is negative (used if ntc=0) 0 2nd order derivative of thermistor function is positive (used if ntc=1) subdec 1 2nd order derivative of thermistor function is negative (used if ntc=1) 0 used thermistor is ptc ntc 1 used thermistor is ntc 0000 offset calibration interval: 0'00" 0001 offset calibration interval: 0'02" 0010 offset calibration interval: 0'17" 0011 offset calibration interval: 0'19" 0100 offset calibration interval: 1'07" 0101 offset calibration interval: 1'09" 0110 offset calibration interval: 1'24" 0111 offset calibration interval: 1'26" 1000 offset calibration interval: 2'14" 1001 offset calibration interval: 2'16" 1010 offset calibration interval: 2'31" 1011 offset calibration interval: 2'33" 1100 offset calibration interval: 3'21" 1101 offset calibration interval: 3'23" 1110 offset calibration interval: 3'38" timeos[3:0] 1111 offset calibration interval: 3'40" oscctrl read access: no. the data is accessible for read via spi only from eeprom address 05h. write access: only in test mode for both writing directly to internal registers and writing to eeprom if wp register is correctly set. bgo: reserved read access: no. the data is accessible for read via spi only from eeprom address 06h. write access: only in test mode for both writing directly to internal registers and writing to eeprom if the wp register is correctly set. lpf read access: no. the data is accessible for read via spi only from eeprom address 07h. mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 18 rev 1.0 21-july-2001 3901090313 write access: only in test mode for both writing directly to internal registers and writing to eeprom if the wp register is correctly set. this register keeps the calibration data for the time constants of digital low pass filters of both channels (see section linearisation unit). lpf bit functions bit por val function rsel4 0 refer to adc interface setting 0 enable offset measurement of both ir & temp channels. enosmb 1 disable offset measurement of both ir &temp channels. 0 reserved for future development. reset it for all applications. entav 1 reserved for future development. reset it for all applications. 0 number of averaged offset measurements for ir chain: 512 iros* 1 number of averaged offset measurements for ir chain: 1024 0 number of averaged offset measurements for temp chain: 512 tos* 1 number of averaged offset measurements for temp chain: 1024 number of averaged points for ir measurement 00b 64 01b 128 10b 256 11b 512 lpfir[2:0] 100b 1024 number of averaged points for temp measurement 00b 64 01b 128 10b 256 11b 512 lpft[2:0] 100b 1024 adcreg read access: directly via spi in all modes. write access: directly to internal register in test mode. this register keeps the result from last analog to digital conversion.. irout read access: directly from internal register. write access: directly to internal register in test mode. this register keeps the linearised object temperature. (tobject) register format: bit1514131211109876543210 name d11 d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 ovh ovl fe res d11..d0 : 12 bit temperature data ovh: overflow flag for tambient measurement, ta>tamax, d[11:0] set to fffh ovl: underflow flag for tambient measurement, ta mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 21 rev 1.0 21-july-2001 3901090313 eeprom description mlx90313 contains 128 x 16 eeprom memory. the memory can be accessed through the serial interface. the 11 most significant bits are data bits and the 5 less significant bits are control bits used for the error check and correction system (ecc). after por the asic reads the full eeprom contents, checks it and corrects the single errors (1 wrong bit per address). if higher order error is discovered then the bit ?fatal error? will be set (see confreg1 description in previous section). the memory has two levels of protection. after por the write access to the eeprom will be disabled. the external unit can remove this level of protection writing proper data in wp register. in this case all addresses in range 08-77h will be available for write access. the first and last 8 addresses will still be disabled. the write access to these cells is available only if the write protection is removed and the chip is in test mode. eeprom map overview address list eeprom address write access register name function dec hex irgain1 ir-chain settings 0 00h test mode** irgain2 ir-chain settings 1 01h test mode tempgain temp-chain settings 2 02h test mode confreg1 configuration 3 03h test mode confreg2 configuration 4 04h test mode oscctrl oscillator control 5 05h test mode bgctrl bandgap control 6 06h test mode lpf low pass filter 7 07h test mode calibration look up table linearisation. 8-111 08h-6fh wp* ios-temp initial offset temp-chain 112 70h wp ios-ir initial offset ir-chain 113 71h wp reserved 114 72h wp thcomp1 threshold for comparator comp1 115 73h wp hscomp1 hysteresis for comparator comp1 116 74h wp threl1 threshold for comparator of rel1 117 75h wp hsrel1 hysteresis for comparator of rel1 118 76h wp reserved 119 77h chip-id data 120-127 78h-7fh test mode *wp: write access to eeprom is controlled by the content of the internal register wp **test mode: write access controlled by the internal register wp and only available in test mode the last 8 addresses 0x78 to 0x7f are free to use for the user. they can hold some calibration data or identification number. all data programmed into the eeprom must pass the error checking. therefore, one must add 5 hamming bits to the eeprom data, in the 5 least significant bits. mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 22 rev 1.0 21-july-2001 3901090313 eeprom bit definitions following table gives the bit definitions for all addresses that can be modified by the user. all other addresses contain specific calibration data and should be left unchanged. note that some bits marked ?res? are reserved and should never not be changed by the user. if other bits in such an address must be changed, read original contents first to get the status of the reserved bits. eeprom bit defenitions address registerh b15 b14 b13 b12 b11 b10 b9 b8 (hex) registerl b7b6b5b4b3b2b1b0 0x00 irgain1h endrefdiv endac enln gci7 gci6 gci5 gci4 gci3 irgain1l gci2 gci1 gci0 k h4 h3 h2 h1 0x01 irgain2h agndc3 agndc2 agndc1 agndc0 seldr2 seldr1 seldr0 rsel3 irgain2l rsel2 rsel1 rsel0 k h4 h3 h2 h1 0x02 tempgainh trsel1 trsel0 irsel2 irsel1 irsel0 gct5 gct4 gct3 tempgainl gct2 gct1 gct0 k h4 h3 h2 h1 0x03 confreg1h envr hvsup seladref potmet comp1v comp1p byptemp rel1v confreg1l rel1p res res k h4 h3 h2 h1 0x04 confreg0h iroutc1 iroutc0 toutc1 toutc0 subinc subdec ntc timeos3 confreg0l timeos2 timeos1 timeos0 k h4 h3 h2 h1 0x05 osch res res enagndb res res res res res oscl res res res k h4 h3 h2 h1 0x06 bgh res res res res res res res res bgl res res res k h4 h3 h2 h1 0x07 lpfh rsel4 enosm entav iros tos lpfir2 lpfir1 lpfir0 lpfl lpft2 lpft1 lpft0 k h4 h3 h2 h1 0x73 thcomp1 thr10 thr2 thr9 thr1 thr8 thr0 thr7 k thr6 h4 thr5 h3 thr4 h2 thr3 h1 0x74 hscomp1 hst10 hst9 hst8 hst7 hst6 hst5 hst4 hst3 hst2 hst1 hst0 k h4 h3 h2 h1 0x75 threl1 thr10 thr9 thr8 thr7 thr6 thr5 thr4 thr3 thr2 thr1 thr0 k h4 h3 h2 h1 0x76 hsrel1 hst10 hst9 hst8 hst7 hst6 hst5 hst4 hst3 hst2 hst1 hst0 k h4 h3 h2 h1 0x78 - 0x7f user1..7 udata10 udata9 udata8 udata7 udata6 udata5 udata4 udata3 udata2 udata1 udata0 k h4 h3 h2 h1 eeprom hamming coding all addresses in the eeprom are coded using hamming code. therefore, if one wants to program data into any eeprom address, the hamming bits must be calculated first. this is not done by the there are 11 bits + 4 hamming bits + 1 extra redundant bit in the eeprom. data bits are numbered d10..d0, hamming h4..h1, the extra bit is called k. the bit definitions in the eeprom words are: pos1514131211109876543210 name d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 k h4 h3 h2 h1 the hamming bits are calculated as follows: h1 = p(d0,d1,d3,d4,d6,d8,d10) mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 23 rev 1.0 21-july-2001 3901090313 h2 = p(d0,d2,d3,d5,d6,d9,d10) h3 = p(d1,d2,d3,d7,d8,d9,d10) h4 = p(d4,d5,d6,d7,d8,d9,d10) the extra k bit is calculated as: k = p(d10,d9,d8,d7,d6,d5,d4,d3,d2,d1,d0,h4,h3,h2,h1) note :p is parity over the noted data bits. parity is 1 if the number of ones is odd. when reading eeprom addresses, the numerical value can be found by simply dividing the returned data by 32. mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 24 rev 1.0 21-july-2001 3901090313 90313 algorithm the algorithm of the asic is divided in several operations: ecc, initialization, offset measurement, object and ambient measurement and offset cancellation, linearisation, comparator functions. each of this operation is controlled from the main state machine. the sequence and control of all these state machines is controlled from main state machine. the normal flow of the procedure is show on the diagram below. ecc initialization offset calibration measurement temp. linearisation comp & relay recalibration ir. linearisation por true false main state machine control flow mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 25 rev 1.0 21-july-2001 3901090313 error check and correction (ecc) the asic starts this procedure only after power on reset. the state machine reads all data in the eeprom and corrects all single errors (1 wrong bit per address) if necessary. the wrong information from the eeprom will be refreshed with correct one. in case of double error (2 wrong bits per address) which can only be detected, not corrected, the system will leave the data in the address and will set the flag ?fatal error? (bit 1 in status register). this data is available through spi or pwm. initialization at this step the system reads its configuration from the eeprom. all data from eeprom addresses 00-07h will be filled in the corresponding peripheral registers. after this step the asic is ready for normal operation. offset measurement (offset drift compensation) the offset measurement is run periodically from the main state machine. the customer can select one of 16 possible interval times for offset measurement (see ?confreg0 bit functions?). depending on the selected values for bits iros and tos in lpf register (address 07h in eeprom) the average of 512 or 1024 measurements is stored. the time this measurement takes is about 75ms or 150ms, depending on the number of measurements taken. note that during this time the outputs are kept on their last value before calibration started, so the current temperature is not available during offset calibration. the measured offset results will be stored in iros (for ir amplifier chain) and tos (for temp amplifier chain) registers. measurement and offset cancellation the results from analog to digital conversion for both channels will be the mean of custom defined number of measurements, controlled from the lpf register (address 07 in eeprom). this data will be compensated with corresponding offsets, stored in iros and tos registers and final offset free data will be stored in irdata (for ir amplifier chain) and tdata (for temp amplifier chain) registers. the number of measurements of which the averaging is taken can vary between 64 and 1024 (see ?lpf register bit functions?) and can be selected independently for both channels. linearisation linearisation proceeds in two steps and can be described by the picture below. in the first step the ambient temperature is calculated from the measured signal at tinp-tinn. the system outputs a digital value for the ambient temperature based on the calibration data. the value is stored in a dedicated register and from there available for the dac and pwm (tambient-register, address 0ah). the register can also be read digitally by means of the spi. the system is developed to support different temperature sensors. 3 bits in the configuration register (eeprom address 03h), determine the type of characteristic. ntc defines the first derivative of the temperature sensor (ntc-type is logical 1, ptc-type is logical 0). subdec and incdec define the second derivative of the temperature sensor ( 2 2 dt vrth d ). the result of the linearisation is stored as the 12 msb?s of the tambient-register (or tout-register). the code 000h will correspond to tamin, fffh will correspond to tamax. these two limits are determined by calibration. accordingly the output resolution will be 4096 min max ta ta ? in k per lsb in the second step the value of the ambient temperature is combined with the measured signal at irinp- irinn to obtain a calculated value for the so-called object temperature, based on the calibration data. the value is stored in a dedicated register and from there available for the dac and pwm (tobject-register, address 09h). the register can also be read digitally by means of the spi. the result of the linearisation is stored as the 12 msb?s of the tobject-register (or irout-register). the mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 26 rev 1.0 21-july-2001 3901090313 code 000h will correspond to tomin, fffh will correspond to tomax. these two limits are determined by calibration. accordingly the output resolution will be 4096 min max to to ? in k per lsb. the rm is tor characte ris tic r=f(t a) ta[degc] r(t)/ro the rm opile characte ris tic vir=f(to, ta) to [degc] signal [v] ta vir r lin. unit linearised output irout=a.to+b to [degc] irout [v] linearised output tempout=a.to+b ta [degc] tempout[v] irout tempout when reading the linearised data digitally by means of the spi, a 16-bit word is returned. the 12 msb?s contain the temperature value as described above, the 4 lsb?s form a status register, which is the same for both the irout address and the tout. the meaning of the individual bits is explained in the table below. linearisation status register s[3:0] meaning 1 x x x overflow flag for tambient measurement, ta>tamax, tout[15:4] set to fffh x 1 x x underflow flag for tambient measurement, ta mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 28 rev 1.0 21-july-2001 3901090313 the threshold data can be calculated by the formula: threshold value = 2048 min max min ? ? t t t tthr . where: tthr is the target temperature for the comparator tmin, tmax are the minimum and maximum temperature under calibration. the hysteresis value can be calculated by following formula: hysteresis value = 2048 min max ? t t thys where: thys is the desired hysteresis in deg c. tmin, tmax are the minimum and maximum temperature under calibration both formulas are valid for ambient and ir temperatures. the data for hysteresis must be stored at addresses 74h (for comp1) and 76h (for rel1) after adding the hamming bits in the 5 least significant bit places. refer to hamming coding in eeprom description section for details. pulse width modulation the pwm signal has a period of 102.4ms typical consisting of 2048 clock cycles of 50 s. every frame starts with a leading buffer time, t 1 , during which the signal is always high, as shown in the figure below. the leading buffer time is followed by a slot for the useful data signal, t2 and t3, where the ration t2/(t2+t3) is the representation of the output value. t4 is a slot for signaling of special conditions, such as out of range measurement of the sensor temperature, tambient and the occurrence of a fatal eeprom error, i.e. an error that can no longer be corrected automatically by the ecc circuitry of mlx90313. error signaling band condition duty cycle nominal timing ovh: tambient overflow 68.75 % 70.4 ms ovl: tambient underflow 75 % 76.8 ms fe: fatal error eeprom 81.25% 83.2 ms output signal time t 0 t 8 5 t 8 7 t 8 1 t 1 t 2 +t 3 t 4 :error signaling band t 5 t 16 13 t 16 12 t 16 11 ovh ovl fe valid data output band serial interface protocol the digital interface implemented in mlx90313 is spi compatible. it can be used to access the on-chip eeprom and all internal registers. the chip will always work as a slave device. the format of any mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 29 rev 1.0 21-july-2001 3901090313 command is always 32 bits: 8 bits for the operation code, 8 bits for the address and 16 bits of data. the communication protocol is presented below. cs sclk sdi sdo c7 c0 c1 c2 c3 c4 c5 c6 a7 a0 a1 a2 a3 a4 a5 a6 d15 d8 d9 d10 d11 d12 d13 d14 x x c7 c0 c1 c2 c3 c4 c5 c6 a7 a0 a1 a2 a3 a4 a5 a6 d15 d8 d9 d10 d11 d12 d13 d14 d7 d0 d1 d2 d3 d4 d5 d6 x write command cs sclk sdi sdo c7 c0 c1 c2 c3 c4 c5 c6 d7 d0 d1 d2 d3 d4 d5 d6 d15 d8 d9 d10 d11 d12 d13 d14 x x c7 c0 c1 c2 c3 c4 c5 c6 a7 a 0 a 1 a 2 a3 a4 a5 a6 x read command every write command starts with a high to low transition of cs and ends by a low to high transition of cs after 32 periods of the serial data clock (sclk). mlx90313 reads the data present on sdi on the rising edge of the clock. with a delay of 8 periods of the serial clock, the spi will repeat the opcode, address and the first 8 bits of data on pin sdo. this allows the external master to check command and address and terminate the operation in case of an error by forcing cs high before the end of the complete command cycle, i.e. before the end of the 32 clock periods. the read command is build up similarly, except that no data has to be passed of course. on sdo the opcode will be followed directly by the requested data, the address is not returned in this case. the data on sdo is valid on the rising edge of the clock. in case of a read command, the spi output will be valid on sdo starting on the 17 th rising edge of the clock (after cs low) as indicated in the figure above. timing/speed the bit-rate depends on the serial data clock (sclk) supplied by the master controller and is limited to 125kb/s. the timing requirements are given in the figure and table below cs sdo sdi sclk tsclk tcls tsch tsu thd tdv spi timing requirements symbol parameter value unit tsclk sclk period min 8 s tcls cs low to sclk high min 50 ns tsch sclk low to cs high min 50 ns tsu data in setup time min 200 ns thd data in hold time min 200 ns mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 30 rev 1.0 21-july-2001 3901090313 tdv data out valid min 1 s operation codes the operation code is the first series of 8bits in a command, c[7:0] in the figure on the protocol above. below table summarizes the operations available in mlx90313. operation codes mnem. c[7:0] command wr x101x0xx write internal register rd x10010xx read internal register wepr 0001xxxx write eeprom er 00 1 xxxxx erase eeprom repr x0001xxx read eeprom blwr 1001xxxx block write eeprom bler 10 1 xxxxx block erase eeprom mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 31 rev 1.0 21-july-2001 3901090313 applications information opa irinp opa control and support blocks tinn tinp irinn agnd ir sensor thermisto r irout tempout vdd1 vdd cref vss mlx90313 rbias ir+ rsens ir- vss mlx9024 7 10u 100k high prec. digital a/d a/d d/a d/a to ta comp rel1 sw2 sw1 vref ta 12 vrefp comp 12 spi micro-controller i/o-port typical application diagram in the above application diagram, a simple thermometer with alarm function is depicted. as external components there are only a thermopile (like the mlx90247x) and a current setting resistor is used. because the current needs to be constant over temperature and time, it is advised to use a precision resistor. the tempout pin is the output of a comparator which compares the measured object temperature with the threshold set by the external potentiometer. the second comparator operates the relay. it compares the ambient temperature with a fixed threshold programmed in eeprom. both ambient and object temperatures can be read continously by the microprocessor using the spi interface. for more application examples, take a look at our mlx90601 infrared thermometer module, which incorporates a mlx90247 thermopile sensor and the mlx90313 ir sensor interface. mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 32 rev 1.0 21-july-2001 3901090313 support tools in a short time melexis will provide a demo board which can demonstrate all mlx90313?s features. this will come with software which allows easy configuration of the mlx90313. please have a look at www.melexis.com for latest info. esd precautions electronic semiconductor products are sensitive to electro static discharge (esd). always observe electro static discharge control procedures whenever handling semiconductor products. faq q: when is the mlx90313 available ? a: currently melexis only delivers the mlx90313 as part of the mlx90601x infrared thermometer module. please refer to mlx90601 datasheet for details. samples can be obtained q3/2001, full production starts q4/2001. glossary of terms adc analog-to-digital converter ambient compensation the ir signal captured by a thermopile sensor is not only dependent on the temperature of the object (tobject) but also on the temperature of the sensor itself. therefore the ir signal is compensated for this effect by means of the measured sensor temperature (tambient). this rather complex calculation is performed in the linearisation unit of mlx90313. asic application specific integrated circuit band-gap circuit to generate accurate absolute voltages. usually they are independent of temperature and supply voltage, like the one used in the mlx90313 chopper compensated amplifier special amplifier configuration aimed at ultra low offset dac digital-to-analog converter differential nonlinearity (dnl) the deviation of any code from an ideal 1 lsb step ecc error checking and correction eeprom non-volatile memory that can be electrically erased and rewritten. this type of memory is used to store configuration and calibration data needed by the mlx90313. hamming coding by giving a message a extra number of bits (= so called hamming bits), one can not only detect, but also correct a error that occurs in the stored data or the hamming bits. the eeprom memory of the mlx90313 uses hamming coding to do a error check and correction if needed and possible. integral nonlinearity (inl) this is the maximum deviation from the ideal output curve and the actual output ir infrared. every object emits infrared radiation in relation to its temperature. this effect can be used to measure this temperature without the need for physical contact. linearisation the signal from a thermopile is not linear with the object temperature. mlx90313 is therefore equipped with a digital calculation unit that produces an output that is linear with the object temperature. lsb,msb least significant bit, most significant bit ntc see thermistor. pga programmable gain amplifier. mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 33 rev 1.0 21-july-2001 3901090313 por power ?on reset: reset circuit that starts the digital system in a known state whenever the supply voltage is cycled pssr power supply rejection ratio: measure for an amplifier?s immunity to disturbances on the supply connections. ptc see thermistor. spi serial peripheral interface. commonly used 4 wire serial link to connect different circuits over a short distance. ta, tambient, ambient temperature the temperature of the ir sensor. thermistor temperature dependant resistor. basically there are 2 types. the types that increase their resistance with rising temperature are ptc (positive thermal coefficient) type. the ones that decrease their resistance with rising temperature we call ntc (negative thermal coefficient) type. the mlx90313 can work with both types. tobject, to and target temperature commonly used terms in infrared thermometry. it refers to the temperature of the target, at which the ir sensor is ?looking? mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 34 rev 1.0 21-july-2001 3901090313 disclaimer melexis reserves the right to periodically make modifications to product specifications. the information included herein is believed to be accurate and reliable. however, melexis assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. mlx90313 programmable ir sensor interface mlx90313 programmable ir sensor interface page 35 rev 1.0 21-july-2001 3901090313 physical characteristics 10.45 10.15 notes: 1. all dimensions in millimeters. 1.04 0.60 0.32 0.23 0 o to 8 o 7.60 7.40 1.27 0.50 0.33 12.99 12.70 2.66 2.45 0.290 0.127 for the latest version of this document, go to our website at: www.melexis.com or for additional information contact melexis direct: europe and japan: all other locations: phone: +32 13 61 16 31 phone: +1 603 223 2362 e-mail: sales_europe@melexis.com e-mail: sales_usa@melexis.com |
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