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19-1603; Rev 0; 1/00 Octal, 13-Bit Voltage-Output DAC with Parallel Interface General Description The MAX5839 contains eight 13-bit, voltage-output digital-to-analog converters (DACs). On-chip precision output amplifiers provide the voltage outputs. The device operates from +14V/-9V supplies. Its bipolar output voltage swing ranges from +9V to -4V and is achieved with no external components. The MAX5839 has three pairs of differential reference inputs; two of these pairs are connected to two DACs each, and a third pair is connected to four DACs. The references are independently controlled, providing different full-scale output voltages to the respective DACs. The MAX5839 operates within the following voltage ranges: VDD = +7V to +14V, VSS = -5V to -9V, and VCC = +4.75V to +5.25V. The MAX5839 features double-buffered interface logic with a 13-bit parallel data bus. Each DAC has an input latch and a DAC latch. Data in the DAC latch sets the output voltage. The eight input latches are addressed with three address lines. Data is loaded to the input latch with a single write instruction. An asynchronous load input (LD) transfers data from the input latch to the DAC latch. The LD input controls all DACs; therefore, all DACs can be updated simultaneously by asserting the LD pin. An asynchronous CLR input sets the output of all eight DACs to the respective DUTGND input of the op amp. Note that CLR is a CMOS input, which is powered by VDD. All other logic inputs are TTL/CMOS compatible. The "A" grade of the MAX5839 has a maximum INL of 2LSBs, while the "B" grade has a maximum INL of 4LSBs. Both grades are available in 44-pin MQFP packages. o 8 DACs in a Single Package o Buffered Voltage Outputs o Unipolar or Bipolar Voltage Swing to +9V and -4V o 22s Output Settling Time o Drives up to 10,000pF Capacitive Load o Low Output Glitch: 30mV o Low Power Consumption: 10mA (typ) o Small Package: 44-Pin MQFP o Double-Buffered Digital Inputs o Asynchronous Load Updates All DACs Simultaneously o Asynchronous CLR Forces All DACs to DUTGND Potential Features o Full 13-Bit Performance Without Adjustments MAX5839 Ordering Information PART MAX5839ACMH MAX5839BCMH MAX5839AEMH MAX5839BEMH TEMP. RANGE 0C to +70C 0C to +70C -40C to +85C -40C to +85C PINPACKAGE 44 MQFP 44 MQFP 44 MQFP 44 MQFP INL (LSB) 2 4 2 4 Pin Configuration OUTE DUTGNDEF OUTF OUTG 37 36 35 34 Applications Industrial Process Controls Arbitrary Function Generators Avionics Equipment Minimum Component Count Analog Systems Digital Offset/Gain Adjustment SONET Applications Automatic Test Equipment (ATE) TOP VIEW 44 43 42 41 40 39 38 OUTB OUTC DUTGNDCD OUTD REFCDEFREFCDEF+ VDD DUTGNDAB OUTA REFABREFAB+ VDD VSS LD A2 A1 A0 CS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 33 32 31 30 29 28 27 26 25 24 23 MAX5839 DUTGNDGH OUTH REFGHREFGH+ VSS CLR D12 D11 D10 D9 D8 Functional Diagram appears at end of data sheet. WR VCC GND D0 D1 D2 D3 D4 D5 D6 D7 MQFP ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. Octal, 13-Bit Voltage-Output DAC with Parallel Interface MAX5839 ABSOLUTE MAXIMUM RATINGS VDD to GND ...........................................................-0.3V to +17V VSS to GND ........................................................... -11V to +0.3V VCC to GND ............................................................ -0.3V to +6V A_, D_, WR, CS, LD, CLR to GND.............+0.3V to (VCC + 0.3V) REF_ _ _ _+, REF_ _ _ _-, DUTGND_ _ ..................................(VSS - 0.3V) to (VDD + 0.3V) OUT_ ..........................................................................VDD to VSS Maximum Current into REF_ _ _ _ _, DUTGND_ _ ...........10mA Maximum Current into Any Signal Pin ............................. 50mA OUT_ Short-Circuit Duration to VDD, VSS, and GND .......... 1sec Continuous Power Dissipation (TA = +70C) 44-Pin MQFP (derate 11.1mW/C above +70C)......... 870mW Operating Temperature Ranges MAX5839_CMH ................................................... 0C to +70C MAX5839_EMH................................................. -40C to +85C Junction Temperature ..................................................... +150C Storage Temperature Range ............................ -65C to +150C Lead Temperature (soldering, 10s) ................................ +300C Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VDD = +14V, VSS = -9V, VCC = +5V, VGND = VDUTGND_ _ = 0, VREF_ _ _ _+ = +4.500V, VREF_ _ _ _- = -2.000V, RL = 10k, CL = 50pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER Resolution Relative Accuracy Differential Nonlinearity Zero-Scale Error Full-Scale Error Gain Error Gain Temperature Coefficient DC Crosstalk REFERENCE INPUTS Input Resistance Input Current REF_ _ _ _+ Input Range REF_ _ _ _- Input Range (REF_ _ _ _+) - (REF_ _ _ _-) Range ANALOG OUTPUTS Maximum Output Voltage Minimum Output Voltage Resistive Load to GND Capacitive Load to GND DC Output Impedance (Note 2) (Note 1) 5 10,000 0.5 9 VDD - 2 VSS + 2 -4 V V k pF 0.5 -2.0 2 1 1 10 4.5 -0.5 6.5 M A V V V (Note 1) (Note 1) SYMBOL N INL DNL ZSE FSE MAX5839A MAX5839B Guaranteed monotonic 2 4 2 0.15 14 CONDITIONS MIN 13 2 4 1 4 8 5 20 75 TYP MAX UNITS Bits LSB LSB LSB LSB LSB ppm FSR/C V STATIC PERFORMANCE (ANALOG SECTION) 2 _______________________________________________________________________________________ Octal, 13-Bit Voltage-Output DAC with Parallel Interface ELECTRICAL CHARACTERISTICS (continued) (VDD = +14V, VSS = -9V, VCC = +5V, VGND = VDUTGND_ _ = 0, VREF_ _ _ _+ = +4.500V, VREF_ _ _ _- = -2.000V, RL = 10k, CL = 50pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER Input Impedance per DAC Input Current per DAC Input Range DIGITAL INPUTS Input Voltage High Input Voltage Low Input Capacitance Input Current POWER SUPPLIES VDD Analog Power-Supply Range VSS Analog Power-Supply Range Digital Power Supply Positive Supply Current Negative Supply Current Digital Supply Current PSRR, VOUT / VDD PSRR, VOUT / VSS VDD VSS VCC IDD ISS ICC RL = RL = (Note 3) (Note 4) VDD = 14V 5% VSS = -9V 5% 94 98 7 -9 4.75 5 10 9 14 -5 5.25 13 12 0.5 5 V V V mA mA mA dB dB VIH VIL CIN IIN (Note 1) VIN = 0 or VCC -1 2.4 0.8 10 1 V V pF A (Note 1) SYMBOL CONDITIONS MIN 40 -165 -2 TYP 84 100 2 MAX UNITS k A V DUTGND_ _ CHARACTERISTICS MAX5839 INTERFACE TIMING CHARACTERISTICS (VDD = +14V, VSS = -9V, VCC = +5V, VGND = VDUTGND_ _ = 0, VREF_ _ _ _+ = +4.500V, VREF_ _ _ _- = -2.000V, Figure 2, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER CS Pulse Width Low WR Pulse Width Low LD Pulse Width Low CS Low to WR Low CS High to WR High Data Valid to WR Setup Data Valid to WR Hold Address Valid to WR Setup Address Valid to WR Hold SYMBOL t1 t2 t3 t4 t5 t6 t7 t8 t9 CONDITIONS MIN 50 50 50 0 0 50 0 15 0 TYP MAX UNITS ns ns ns ns ns ns ns ns ns _______________________________________________________________________________________ 3 Octal, 13-Bit Voltage-Output DAC with Parallel Interface MAX5839 DYNAMIC CHARACTERISTICS (VDD = +14V, VSS = -9V, VCC = +5V, VGND = VDUTGND_ _ = 0, VREF_ _ _ _+ = +4.500V, VREF_ _ _ _- = -2.000V, RL = 10k, CL = 50pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER Output Settling Time Output Slew Rate Digital Feedthrough Digital Crosstalk Digital-to-Analog Glitch Impulse DAC-to-DAC Crosstalk Channel-to-Channel Isolation Output Noise Spectral Density Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: At = 1kHz (Note 5) (Note 6) SYMBOL CONDITIONS To 1/2LSB of full scale MIN TYP 22 1 3 3 120 3 100 120 MAX UNITS s V/s nVs nVs nVs nVs dB nV/Hz Guaranteed by design. Not production tested. Guaranteed by design when 220 resistor is in series with CL = 10,000pF. All digital inputs (D_, A_, WR, CS, LD, and CLR) at GND or VCC potential. All digital inputs (D_, A_, WR, CS, LD, and CLR) at +0.8V or +2.4V. All data inputs (D0 to D12) transition from GND to VCC, with WR = VCC. All digital inputs (D_, A_, WR, CS, LD, and CLR) at +0.8V or +2.4V. Typical Operating Characteristics (VDD = +14V, VSS = -9V, VCC = +5V, VGND = VDUTGND_ _ = 0, VREF_ _ _ _+ = +4.500V, VREF_ _ _ _- = -2.000V, TA = +25C, unless otherwise noted.) INTEGRAL NONLINEARITY vs. DIGITAL CODE MAX5260-01 DIFFERENTIAL NONLINEARITY vs. DIGITAL CODE MAX5260-02 INL AND DNL ERROR vs. TEMPERATURE MAX5260-03 0.4 0.3 0.2 0.4 0.3 0.2 0.4 INL 0.3 ERROR (LSB) 0 -0.1 -0.2 -0.3 -0.4 0 2048 4096 DIGITAL CODE 6144 8192 DNL (LSB) INL (LSB) 0.1 0.1 0 -0.1 -0.2 -0.3 -0.4 0 2048 4096 DIGITAL CODE 6144 8192 0.2 DNL 0.1 0 0 10 20 30 40 50 60 70 TEMPERATURE (C) 4 _______________________________________________________________________________________ Octal, 13-Bit Voltage-Output DAC with Parallel Interface Typical Operating Characteristics (continued) (VDD = +14V, VSS = -9V, VCC = +5V, VGND = VDUTGND_ _ = 0, VREF_ _ _ _+ = +4.500V, VREF_ _ _ _- = -2.000V, TA = +25C, unless otherwise noted.) ZERO-SCALE AND FULL-SCALE ERROR vs. TEMPERATURE MAX5260-04 MAX5839 IDD AND ISS vs. TEMPERATURE (UNLOADED) MAX5260-05 DIGITAL SUPPLY CURRENT vs. TEMPERATURE MAX5260-06 0.20 0.15 0.10 ERROR (LSB) 10.4 10.2 10.0 9.8 IDD, ISS (mA) 9.6 9.4 9.2 9.0 8.8 8.6 8.4 8.2 ISS IDD 25 23 SUPPLY CURRENT (A) 70 0.05 0 -0.05 -0.10 -0.15 -0.20 0 10 20 30 40 50 60 70 TEMPERATURE (C) ZERO SCALE FULL SCALE 21 19 17 15 0 25 TEMPERATURE (C) 0 10 20 30 40 50 60 70 TEMPERATURE (C) REFERENCE INPUT FREQUENCY RESPONSE MAX5260-07 SETTLING TIME vs. CAPACITIVE LOAD MAX5260-08 LARGE-SIGNAL STEP RESPONSE D12 5V/div MAX5260-09 5 0 -5 AMPLITUDE (dB) -10 -15 -20 -25 -30 -35 -40 1k 10k 100 90 80 SETTLING TIME (s) 70 60 50 40 30 20 10 0 REF_ _ _ _ _ = 200mVp-p OUT 1V/div 100k FREQUENCY (Hz) 1M 10M 10 100 1000 10k 100k 5s/div CAPACITIVE LOAD (pF) POSITIVE SETTLING TIME MAX5260-10 NEGATIVE SETTLING TIME LD MAX5260-11 NOISE VOLTAGE DENSITY vs. FREQUENCY MAX5260-12 1000 NOISE VOLTAGE DENSITY (nV/Hz) 100 LD OUT 1mV/div OUT 1mV/div 5s/div 5s/div 10 100 1k 10k FREQUENCY (Hz) _______________________________________________________________________________________ 5 Octal, 13-Bit Voltage-Output DAC with Parallel Interface MAX5839 Typical Operating Characteristics (continued) (VDD = +14V, VSS = -9V, VCC = +5V, VGND = VDUTGND_ _ = 0, VREF_ _ _ _+ = +4.500V, VREF_ _ _ _- = -2.000V, TA = +25C, unless otherwise noted.) MAJOR CARRY GLITCH IMPULSE (0xFFFF-0x10000) MAX5260-13 MAJOR CARRY GLITCH IMPULSE (0x1000-0xFFF) MAX5260-14 GAIN ERROR vs. VREF (VREF+ - VREF-) 0.3 0.2 GAIN ERROR (LSB) 0.1 0 -0.1 -0.2 -0.3 MAX5260-15 0.4 LD 5V/div LD 5V/div OUT 5mV/div OUT 5mV/div 2s/div 2s/div 0 2 4 VREF (V) 6 8 10 DIFFERENTIAL NONLINEARITY (MAX, MIN) vs. VREF (VREF+ - VREF-) 0.20 0.15 DNL (MAX, MIN) (LSB) INL (MAX, MIN) (LSB) 0.10 0.05 0 -0.05 -0.10 -0.15 -0.20 -0.25 0 2 4 VREF (V) 6 8 10 -0.2 -0.3 0 MAX5260-16 INTEGRAL NONLINEARITY (MAX, MIN) vs. VREF (VREF+ - VREF-) 0.4 0.3 0.2 0.1 0 -0.1 MAX5260-19 0.25 0.5 2 4 VREF (V) 6 8 10 FULL-SCALE ERROR vs. VREF (VREF+ - VREF-) MAX5260-18 ZERO-SCALE ERROR vs. VREF (VREF+ - VREF-) -0.2 -0.4 MAX5260-17 0 -0.2 -0.4 FSE (LSB) 0 ZSE (LSB) -0.6 -0.8 -1.0 -1.2 -0.6 -0.8 -1.0 -1.2 0 2 4 VREF (V) 6 8 10 -1.4 -1.6 0 2 4 VREF (V) 6 8 10 6 _______________________________________________________________________________________ Octal, 13-Bit Voltage-Output DAC with Parallel Interface MAX5839 Pin Description PIN 1 2 3 4 5, 38 6, 29 7 8 9 10 11 12 NAME DUTGNDAB OUTA REFABREFAB+ VDD VSS LD A2 A1 A0 CS WR FUNCTION Device Sense Ground Input for OUTA and OUTB. In normal operation, OUTA and OUTB are referenced to DUTGNDAB. When CLR is low, OUTA and OUTB are forced to the potential on DUTGNDAB. DAC A Buffered Output Voltage Negative Reference Input for DACs A and B Positive Reference Input for DACs A and B Positive Analog Power Supply. Normally set to +14V. Connect both pins to the supply voltage. See Grounding and Bypassing section for bypass requirements. Negative Analog Power Supply. Normally set to -9V. Connect both pins to the supply voltage. See Grounding and Bypassing section for bypass requirements. Load Input. Drive this asynchronous input low to transfer the contents of the input latches to their respective DAC latches. DAC latches are transparent when LD is low and latched when LD is high. Address Bit 2 (MSB) Address Bit 1 Address Bit 0 (LSB) Chip Select. Active-low input. Write Input. Active-low strobe for conventional memory write sequence. Input data latches are transparent when WR and CS are both low. WR latches data into the DAC input latch selected by A2-A0 on the rising edge of CS. Digital Power Supply. Normally set to +5V. See Grounding and Bypassing section for bypass requirements. Ground Data Bits 0-12. Offset binary coding. Clear Input. Drive CLR low to force all DAC outputs to the voltage on their respective DUTGND _ _. Does not affect the status of internal registers. All DACs return to their previous levels when CLR goes high. Positive Reference Input for DACs G and H Negative Reference Input for DACs G and H 13 14 15-27 28 30 31 VCC GND D0-D12 CLR REFGH+ REFGH- _______________________________________________________________________________________ 7 Octal, 13-Bit Voltage-Output DAC with Parallel Interface MAX5839 Pin Description (continued) PIN 32 33 34 35 36 37 39 40 41 42 43 44 NAME OUTH DUTGNDGH OUTG OUTF DUTGNDEF OUTE REFCDEF+ REFCDEFOUTD DUTGNDCD OUTC OUTB DAC H Buffered Output Voltage Device Sense Ground Input for OUTG and OUTH. In normal operation, OUTG and OUTH are referenced to DUTGNDGH. When CLR is low, OUTG and OUTH are forced to the potential on DUTGNDGH. DAC G Buffered Output Voltage DAC F Buffered Output Voltage Device Sense Ground Input for OUTE and OUTF. In normal operation, OUTE and OUTF are referenced to DUTGNDEF. When CLR is low, OUTE and OUTF are forced to the potential on DUTGNDEF. DAC E Buffered Output Voltage Positive Reference Input for DACs C, D, E, and F Negative Reference Input for DACs C, D, E, and F DAC D Buffered Output Voltage Device Sense Ground Input for OUTC and OUTD. In normal operation, OUTC and OUTD are referenced to DUTGNDCD. When CLR is low, OUTC and OUTD are forced to the potential on DUTGNDCD. DAC C Buffered Output Voltage DAC B Buffered Output Voltage FUNCTION 8 _______________________________________________________________________________________ Octal, 13-Bit Voltage-Output DAC with Parallel Interface _______________Detailed Description CLR R R OUT 2R 2R 2R 2R 2R 2R MAX5839 Analog Section The MAX5839 contains eight 13-bit voltage-output DACs. These DACs are "inverted" R-2R ladder networks that convert 13-bit digital inputs into equivalent analog output voltages, in proportion to the applied reference voltages (Figure 1). The MAX5839 has three positive reference inputs (REF_ _ _ _+) and three negative reference inputs (REF_ _ _ _-). The difference from REF_ _ _ _+ to REF_ _ _ _- , multiplied by two, sets the DAC output span. In addition to the differential reference inputs, the MAX5839 has four analog-ground input pins (DUTGND_ _). When CLR is high (unasserted), the voltage on DUTGND_ _ offsets the DAC output voltage range. If CLR is asserted, the output amplifier is forced to the voltage present on DUTGND_ _. D0 D11 D12 DUTGND REF- REF+ Figure 1. DAC Simplified Circuit Reference and DUTGND Inputs All of the MAX5839's reference inputs are buffered with precision amplifiers. This allows the flexibility of using resistive dividers to set the reference voltages. Because of the relatively high multiplying bandwidth of the reference input (188kHz), any signal present on the reference pin within this bandwidth is replicated on the DAC output. The DUTGND pins of the MAX5839 are connected to the negative source resistor (nominally 84k) of the output amplifier. The DUTGND pins are typically connected directly to analog ground. Each of these pins has an input current that varies with the DAC digital code. If the DUTGND pins are driven by external circuitry, budget 200A per DAC for load current. t1 CS t4 t2 WR t8 t9 A0-A2 t5 t6 D0-D12 t7 Output Buffer Amplifiers The MAX5839's voltage outputs are internally buffered by precision gain-of-two amplifiers with a typical slew rate of 1V/s. With a full-scale transition at its output, the typical settling time to 1/2LSB is 22s. This settling time does not significantly vary with capacitive loads less than 10,000pF. t3 t3 LD (NOTE 3) Output Deglitching Circuit The MAX5839's internal connection from the DAC ladder to the output amplifier contains special deglitch circuitry. This glitch/deglitch circuitry is enabled on the falling edge of LD to remove the glitch from the R-2R DAC. This enables the MAX5839 to exhibit a fraction of the glitch impulse energy of parts without the deglitching circuit. NOTES: 1. ALL INPUT RISE AND FALL TIMES MEASURED FROM 10% TO 90% OF +5V. tr = tf = 5ns. 2. MEASUREMENT REFERENCE LEVEL IS (VINH + VINL) / 2. 3. IF LD- IS ACTIVATED WHILE WR IS LOW, THEN LD- MUST STAY LOW FOR t3 OR LONGER AFTER WR GOES HIGH. Figure 2. Digital Timing Diagram _______________________________________________________________________________________ 9 Octal, 13-Bit Voltage-Output DAC with Parallel Interface MAX5839 Digital Inputs and Interface Logic All digital inputs are compatible with both TTL and CMOS logic. The MAX5839 interfaces with microprocessors using a data bus at least 13 bits wide. The interface is double buffered, allowing simultaneous updating of all DACs. There are two latches for each DAC (see Functional Diagram): an input latch that receives data from the data bus, and a DAC latch that receives data from the input latch. Address lines A0, A1, and A2 select which DAC's input latch receives data from the data bus, as shown in Table 1. Both the input latches and the DAC latches are transparent when CS, WR, and LD are all low. Any change of D0-D12 during this condition appears at the output instantly. Transfer data from the input latches to the DAC latches by asserting the asynchronous LD signal. Each DAC's analog output reflects the data held in its DAC latch. All control inputs are level triggered. Table 2 is an interface truth table. Input Write Cycle Data can be latched or transferred directly to the DAC. CS and WR control the input latch, and LD transfers information from the input latch to the DAC latch. The input latch is transparent when CS and WR are low, and the DAC latch is transparent when LD is low. The address lines (A0, A1, A2) must be valid for the duration that CS and WR are low (Figure 1), to prevent data from being inadvertently written to the wrong DAC. Data is latched within the input latch when either CS or WR is high. Loading the DACs Taking LD high latches data into the DAC latches. If LD is brought low when WR and CS are low, the DAC addressed by A0, A1, and A2 is directly controlled by the data on D0-D12. This allows the maximum digital update rate; however, it is sensitive to any glitches or skew in the input data stream. Asynchronous Clear The MAX5839 has an asynchronous clear pin (CLR) that, when asserted, sets all DAC outputs to the voltage present on their respective DUTGND pins. Deassert CLR to return the DAC output to its previous voltage. Note that CLR does not clear any of the internal digital registers. Table 1. MAX5839 DAC Addressing A2 0 0 0 0 1 1 1 1 A1 0 0 1 1 0 0 1 1 A0 0 1 0 1 0 1 0 1 FUNCTION DAC A input latch DAC B input latch DAC C input latch DAC D input latch DAC E input latch DAC F input latch DAC G input latch DAC H input latch Applications Information Multiplying Operation The MAX5839 can be used for multiplying applications. Its reference accepts both DC and AC signals. Since the reference inputs are unipolar, multiplying operation is limited to two quadrants. See the graphs in the Typical Operating Characteristics for dynamic performance of the DACs and output buffers. Table 2. Interface Truth Table CLR X X X X X 0 LD X X X 0 1 X WR 0 X 1 X X X CS 0 1 X X X X FUNCTION Input register transparent Input register latched Input register latched DAC register transparent DAC register latched Outputs of DACs at DUTGND_ _ Outputs of DACs set to voltage defined by the DAC register, the references, and the corresponding DUTGND_ _ Digital Code and Analog Output Voltage The MAX5839 uses offset binary coding. A 13-bit two's complement code is converted to a 13-bit offset binary code by adding 212 = 4096. Output Voltage Range For typical operation, connect DUTGND to signal ground, VREF+ to +4.5V, and VREF- to -2.0V. Table 3 shows the relationship between digital code and output voltage. The DAC digital code controls each leg of the 13-bit R-2R ladder. A code of 0x0 connects all legs of the ladder to REF-, corresponding to a DAC output voltage (VDAC) equal to REF-. A code of 0x1FFF connects all legs of the ladder to REF+, corresponding to a VDAC approximately equal to REF+. 1 1 X X X = Don't care 10 ______________________________________________________________________________________ Octal, 13-Bit Voltage-Output DAC with Parallel Interface Table 3. Analog Voltage vs. Digital Code INPUT CODE 1 1111 1111 1111 1 0000 0000 0000 0 1001 1101 1001 0 0000 0000 0001 0 0000 0000 0000 OUTPUT VOLTAGE (V) +8.998413 +4.500 +600 -3.998586 -4.000 Power Supplies, Grounding, and Bypassing For optimum performance, use a multilayer PC board with an unbroken analog ground. For normal operation, connect the four DUTGND pins directly to the ground plane. Avoid sharing the connections of these sensitive pins with other ground traces. As with any sensitive data acquisition system, connect the digital and analog ground planes together at a single point, preferably directly underneath the MAX5839. Avoid routing digital signals underneath the MAX5839 to minimize their coupling into the IC. For normal operation, bypass VDD and VSS with 0.1F ceramic chip capacitors to the analog ground plane. To enhance transient response and capacitive drive capability, add 10F tantalum capacitors in parallel with the ceramic capacitors. Note, however, that the MAX5839 does not require the additional capacitance for stability. Bypass VCC with a 0.1F ceramic chip capacitor to the digital ground plane. MAX5839 Note: Output voltage is based on REF+ = +4.5V, REF- = -2.0V, and DUTGND = 0. The output amplifier multiplies VDAC by 2, yielding an output voltage range of 2 * REF- to 2 * REF+ (Figure 1). Further manipulation of the output voltage span is accomplished by offsetting DUTGND. The output voltage of the MAX5839 is described by the following equation: DATA VOUT = 2 VREF+ - VREF- + VREF- 13 2 - VOUTGND ( ) Power-Supply Sequencing To guarantee proper operation of the MAX5839, ensure that power is applied to VDD before VSS and VCC. Also ensure that V SS is never more than 300mV above ground. To prevent this situation, connect a Schottky diode between VSS and the analog ground plane, as shown in Figure 3. Do not power up the logic input pins before establishing the supply voltages. If this is not possible and the digital lines can drive more than 10mA, place current-limiting resistors (e.g., 470) in series with the logic pins. where DATA is the numeric value of the DAC's binary input code, and DATA ranges from 0 (2 0 ) to 8191 (213 - 1). The resolution of the MAX5839, defined as 1LSB, is described by the following equation: LSB = 2 REF+ - REF - 2 13 ( ) Reference Selection Because the MAX5839 has precision buffers on its reference inputs, the requirements for interfacing to these inputs are minimal. Select a low-drift, low-noise reference within the recommended REF+ and REF- voltage ranges. The MAX5839 does not require bypass capacitors on its reference inputs. Add capacitors only if the reference voltage source requires them to meet system specifications. VSS VSS VSS MAX5839 1N5817 Minimizing Output Glitch The MAX5839's internal deglitch circuitry is enabled on the falling edge of LD. Therefore, to achieve optimum performance, drive LD low after the inputs are either latched or steady state. This is best accomplished by having the falling edge of LD occur at least 50ns after the rising edge of CS. GND SYSTEM GND Figure 3. Schottky Diode Between VSS and GND ______________________________________________________________________________________ 11 Octal, 13-Bit Voltage-Output DAC with Parallel Interface MAX5839 Driving Capacitive Loads The MAX5839 typically drives capacitive loads up to 0.01F without a series output resistor. However, whenever driving high capacitive loads, it is prudent to use a 220 series resistor between the MAX5839 output and the capacitive load. Chip Information TRANSISTOR COUNT: 10,973 12 ______________________________________________________________________________________ VDD VSS OUTA CLR 13 DATA R REG A DAC A DAC REG A 13 13 ANALOG POWER SUPPLY D0- D12 VCC DAC B OUTB 13 DATA REG B DAC REG B 13 13 GND DIGITAL POWER SUPPLY 13 DAC C DATA REG C DAC REG C 13 13 DUTGNDAB OUTC 13 DAC D DATA REG D DAC REG D 13 13 OUTD 13 DAC E 13 13 DUTGNDCD OUTE ADDRESS DECODE LOGIC 13 DAC F DATA REG F DAC REG F 13 13 DATA REG E DAC REG E OUTF A2 13 DAC G OUTG DATA REG G DAC REG G 13 13 DUTGNDEF A1 A0 CS 13 DAC H DATA REG H DAC REG H 13 13 WR OUTH LD MAX5839 REFABREFAB+ REFGHREFGH+ REFCDEFREFCDEF+ MAX5839 ______________________________________________________________________________________ DUTGNDGH Octal, 13-Bit Voltage-Output DAC with Parallel Interface Functional Diagram 13 Octal, 13-Bit Voltage-Output DAC with Parallel Interface MAX5839 Package Information MQFP44.EPS 14 ______________________________________________________________________________________ Octal, 13-Bit Voltage-Output DAC with Parallel Interface MAX5839 NOTES ______________________________________________________________________________________ 15 Octal, 13-Bit Voltage-Output DAC with Parallel Interface MAX5839 NOTES Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. |
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