general description the max1455 evaluation kit (ev kit) demonstrates resis-tive element sensor compensation and calibration using the max1455 and a computer. the kit includes an assembled and tested pcb, which is available with a factory-calibrated sensor (max1455evkit-cs) or with- out a sensor (max1455evkit-ns). the software and computer are not required for performing the initial per- formance evaluation of the sensor option since the ev kit is already compensated. a 10-pin ribbon cable con- nects the ev board to a serial-key adapter, MAX1452KEY, that plugs into a computer serial port, allowing the board to be evaluated inside an environ- mental chamber. the software requires a pc compati- ble with windows 95/98/2000/xp. features ? proven pcb layout ? convenient on-board test points ? fully assembled and tested ? optional pressure sensor (max1455evkit-cs) ? factory-calibrated over temperature(max1455evkit-cs) ? labview -based software evaluates: max1455 max1455 evaluation kit ________________________________________________________________ maxim integrated products 1 19-1032; rev 0; 5/08 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim's website at www.maxim-ic.com. ev kit component list key component list ordering information labview is a registered trademark of national instruments, corp. designation qty description c1 1 470? 10v electrolytic capacitor c2, c4, c6 3 0.1? x7r ceramic capacitors c3, c5 2 1? x7r ceramic capacitors d1 1 5.6v zener diode d2 0 dual diode, not installed j1 0 2-pin header, not installed -cs 0 2-pin header, not installed j2 -ns 1 2-pin header?horted j3 1 2-pin header -cs 1 2-pin header?horted j4 -ns 0 2-pin header, not installed p1 1 10-pin header p2, p3, p4 3 4mm banana sockets;connect +5v, gnd, out r1 1 10 ?% resistor r2 1 4.7k ?% resistor r3 1 10 ?% resistor r4 1 30 ?% resistor s1 1 novasensor (fremont, ca)nph-8-100gh (8-pin to package, 100kpa gauge) s2 0 unused, alternate sensor site designation qty description s3 1 8-pin dil header, alternate sensorconnector sp1?p4 4 split pads;cut tracks to allow connection of sensor at s3 sp5 1 split pad; confi g ur e on- b oar d op am p as b uffer ; cut tracks to allow use of op amp u1 1 max1455aae u1 1 max1455aap designation qty description c1 1 220? 10v electrolytic capacitor(radial lead) panasonic ece-a1aka221 digi-key p832-nd c2, c3, c5 3 0.33? ?0%, 25v x7r ceramiccapacitors* (1206) taiyo yuden tmk316bj334kf or equivalent murata grm319r71e334k c4 1 0.047? ?0%, 50v x7r ceramiccapacitor (1206) kemet c1206c473k5ractu digi-key 399-1246-1-nd part type max1455evkit-cs ev kit max1455evkit-ns ev kit MAX1452KEY* serial key adapter windows is a registered trademark of microsoft corp. * MAX1452KEY is also used for max1455evkit and is included in max1455evkit package. downloaded from: http:///
evaluates: max1455 max1455 evaluation kit 2 _______________________________________________________________________________________ component suppliers key component list (continued) designation qty description c6 1 10? 10v tantal um cap aci tor ( r case) panasonic ecs-t1ax106rdigi-key pcs2106ct-nd c7?12 6 0.1? ?0%, 25v ceramiccapacitors* (0805) murata grm21br71e104k or equivalent d1 1 switching diode 30v, 0.2apanasonic ma715-(tx) digi-key ma715ct-nd d2 1 diode bar74zetex bar74zx j1, j2, j4 3 2-pin headers, gold (0.1in centers)(cut from 36-pin strip) sullins pzc36saan digi-key s1011-36-nd j3 1 3-pin header, gold (0.1in center)(cut from 36-pin strip) sullins pzc36saan digi-key s1011-36-nd j1?4 4 shunts (j1 = open, j2 = shorted, j3pins = 2/3 shorted (lower two pins), j4 = shorted) sullins ssc024an digi-key s9002-nd p1 1 low-profile header 2 x 5 0.1 centers3m 2510-6002ub digi-key mhb10k-nd p2 1 9-pin d-subconnector amp 747905-2 digi-key a2047-nd q1, q2 2 power mosfets (8-pin so) fairchild nds8958 designation qty description q3, q5, q6 3 npn transistorspanasonic un5214 or un5215ct q4 1 pnp differential transistorpanasonic xp2401 q7 1 n-channnel mosfet zetex zvn4106f r1 1 1 1w resistor (2512) r2, r3 2 110 1/8w resistors (1206) r4 1 470 1/8w resistor (1206) r5, r6 2 47k 1/8w resistors (1206) r7 1 390k 1/8w resistor (1206) r8 1 10k 1/8w resistor (1206) r9, r10 2 2.2k 1/8w resistors (1206) rl1, rl2 2 ultra-reed relayshamlin he3621a0510 digi-key he207-nd u1 1 op amp (sot23)*maxim max4490auk u2 1 ic, hex inverter (14 so)texas instruments sn74hc04dr digi-key 296-1189-1-nd u3 1 quad 2 input (14 so)texas instruments sn74hc00dr digi-key 296-1187-1-nd u4 1 rs-232 +5v driver/receiver*maxim max3387ecug 1 MAX1452KEY serial board, pcb supplier phone website digi-key corp. 800-344-4539 www.digikey.com kemet corp. 864-963-6300 www.kemet.com murata electronics north america, inc. 770-436-1300 www.murata-northamerica.com quest components 626-333-5858 www.questcomp.com * indicates that part is normally consigned by maxim. downloaded from: http:///
quick start required equipment precision-regulated +5v power supply multimeter with at least five significant digits sensor pressure source procedure use the following quick-start procedure to operate andevaluate the factory calibration accuracy of a max1455 ev board with sensor option. 1) download and install the max1455 ev kit software on your pc. 2) run port98nt.exe (from the start menu or max1455 folder) to load the device driver for pc iocommunication. 3) connect a 5v power supply to the +5v and gnd terminals on the ev kit. 4) connect a dvm between out and gnd. 5) determine whether the ev board will run in analog or digital mode: factory setting of the -cs type is analog mode.factory setting of the -ns type is digital mode. 6) for analog mode, make sure jumper j2 is removed and jumper j4 is present. note: it is not possible to communicate with the max1455 while in analogmode. 7) for digital mode, make sure that jumper j2 is present and jumper j4 is removed before applying power tothe ev board. in addition, make sure that the 10-pin ribbon cable connects the ev board to the serial com- munication module and that the 9-pin connector on the serial module is connected to the pc either directly or through a straight-connected serial cable. max1455 ev kit contents the max1455evkit-cs is shipped fully temp-erature compensated from -40? to +125?. the max1455evkit-ns version of the ev kit is shipped without a sensor. additional material may be included in your ev kit, which are not listed below. max1455 ev board MAX1452KEY interface adapter 10-pin ribbon cable for connecting the key and ev board computer interface adapter ribbon interconnect cable printout of compensation test data (max1455evkit-cs only) five samples of the max1455 straight-connected serial cable for connecting the key and pc overview the objective of the ev kit is to allow the user to learnhow to program the asic using a hands-on approach. to do this, users are encouraged to compensate their own sensors using the ev kit along with the provided software. this kit is intended to be used by engineers familiar with resistive element sensors and their com- pensation techniques. the purpose of the max1455evkit-cs is to demonstrate the capabilities of the max1455 in compensating a typi- cal resistive element sensor. to assist the user in quickly evaluating the asic, the board has been precompensat- ed using a generic, low-pressure sensor such as the novasensor nph8-100g. in the case of the max1455evkit-cs, the test data print- out included in the ev kit is specific to the particular ev board enclosed in the kit. both the test data and the ev board contain a serial number for identification. initial setup see the max1455 ev board (figure 1). four configura-tion jumpers, j1?4, are provided to make the ev board adaptable to a wide range of applications. j1 bypasses the vout isolation resistor and is not normally fitted. j2 unlocks the max1455 digital interface and places the part in digital mode. j3 connects dio to vout for single- pin programming. j4, when fitted, supplies power direct- ly to the max1455. j4 must be removed when operating in digital mode as control of the power line is then provid- ed by the serial-adapter board. two rows of test points are provided to allow the user to probe the pins of the max1455, including the four sensor nodes. if the user wishes to connect an alternative sensor, this can be done using the 8-pin dil socket, s3. when connecting an alternative sensor, the user must also cut the four split pad tracks (sp1?p4) that connect the resident sensor, s1/s2. these pads are located on the reverse side of the board. the 10-way header p1 carries serial data and power to the serial-adapter board. this must be used when the max1455 is in digital mode and allows the user to reprogram the asic through the computer. three 4mm banana sockets (p2, p3, and p4) carry the +5v, out, and gnd signals to the board. note that all the connectors and test pins are labeled on the board. evaluates: max1455 max1455 evaluation kit _______________________________________________________________________________________ 3 do not interconnect the ev board and the key while jumper j4 is in place, as this will permanently damagethe key when power is applied to the ev board. warning! ! downloaded from: http:///
evaluates: max1455 room temperature bench test (max1455evkit-cs) the board output is ratiometric to the supply, and there-fore, a very accurate setting of the supply voltage is required to minimize measurement errors. also, the board contains a zener diode, which helps protect against overvoltage and reverse voltage. the protection circuit enables if the supply becomes less than approx- imately -0.7v or more than approximately +5.6v. the initial electrical connections should be made as follows: 1) connect the negative terminal of the power supply to the 4mm banana socket labeled gnd. 2) connect the positive terminal of the power supply to the 4mm banana socket labeled +5v. 3) connect the dvm to the 4mm banana socket labeled out; the ground return should be connect-ed to the 4mm banana socket labeled gnd. important! to avoid problems with ground loops,noise, and to prevent possible damage to the MAX1452KEY adapter, connect all equipment including the computer (used later) to the same ac circuit and use one common earth ground . if the power supply has a programmable current limit,set it to approximately 100ma. adjust the supply volt- age to +5v and measure the voltage at test point vdd with respect to test point vss. at this point, there shouldbe no connection to the sensor pressure port. since the sensor supplied is a gauge type, the output voltage at the analog connector should read about 0.5v. carefully remove the plastic sensor protector (if sup- plied) and connect a silicone pressure tube to the sen- sor pressure port. grasp the sensor (not the pcb) while fitting the tube in place. perform any requiredpressure controller initialization/calibration procedures, then vent the system. the output voltage should read 0.5v. perform a few pressure cycles to minimize hys- teresis effects. apply full-scale pressure as stated in the test data or as written on the back of the board, and confirm that the output reads 4.5v. the user can also test at other lesser pressures to check for pressure lin- earity errors. extended temperature pressure test additional equipment required: environmental chamber capable of -40? to +125? operation with a noncondensing atmosphere the unit can now be tested at any temperature in the-40? and +125? range. it is advisable to first perform one or two full excursions of temperature and pressure to minimize hysteresis errors. it is recommended that the electronics be conformal coated in any application where condensation of moisture might occur. this was not done to the ev boards, since the user might wish to modify the circuit for specific requirements. since the pcb is not conformal coated, it is important that the environmental chamber not allow condensation to take place. if this should happen, a bake-out at +125? (with no power applied) for a minimum of 1hr is recommended. note that the circuit might behave errat- ically if moisture is allowed to condense on the pcb since weak ionic paths affect some high-impedance nodes on the board. most of the errors after compensation are due to the sen- sor? drift and nonrepeatable behavior. the ev board compensation printout includes the raw sensor output that was measured during compensation at each temperature. users might wish to compare this data with their measure- ments of the sensor output in order to separate sensor errors from asic errors. this can be performed at the sen- sor connector. to avoid attenuating the sensor output sig- nal, it is recommended to use a multimeter with an input impedance greater than 10m for this measurement. important note: download factory-compensated coef-ficients into a file for future reference before overwrit- ing flash content. max1455 evaluation kit 4 _______________________________________________________________________________________ figure 1. evaluation (ev) board layout downloaded from: http:///
evaluates: max1455 max1455 evaluation kit _______________________________________________________________________________________ 5 computer requirements and connections the next logical step after checking the module perfor-mance is to actually edit and reprogram the module using the same sensor. to do so, configure the ev kit for digital operation and connect the digital interface to the computer first. below is a list of the computer requirements: ibm-compatible pc windows 95/98/2000/xp one unused serial port detailed hardware description the max1455 (u1) performs analog temperature com-pensation on piezo-resistive sensors. the max1455 contains the temperature compensation coefficients in its internal eeprom. figure 2 shows the circuit diagram of the ev board. figures 3? illustrate the pcb component placement and wiring details. the max1455 has a single-wire digital interface that can be connected to the output to maintain a true 3-wire sys- tem. the MAX1452KEY interface adapter converts and buffers the outputs from the computer serial port to com- municate with the asic. the adapter also controls power to the ev board when in digital mode. this configuration allows power resets to be performed under software control. the adapter operates internally at 5v. the ratiometricity tests of the evaluation board should be limited to 4.5v to 5.5v while the digital connector is in place. this requirement is to prevent logic-level mismatch and the activation of any biasing protection diodes in the front end of the digital circuits. figure 7 shows the adapter circuit diagram and figures 8, 9, and 10 provide pcb component placement and wiring information. replacing the sensor (max1455evkit-cs) the factory-calibrated sensor can be replaced by auser-provided sensor. it is recommended to become fully familiarized with the basic operation of the asic and the software before attempting to remove the sen-sor supplied with the board and replacing it with the user sensor. the max1455 works with 4-wire closed wheatstone bridge-configured sensors. an 8-pin dil socket is provided for alternative sensor mounting. the pinout for this connector is given in table 1. alternatively, the user can test the asic using an artifi- cial bridge consisting of four discrete resistors. some general knowledge of the user? sensor parameters must be known in order to set the initial coefficients. this way, the asic is not overloaded (i.e., output satu- rated). it is recommended that the sensor wires be kept as short as possible to minimize system noise. at this point, refer to the compensation procedure section in the max1455 user manual for a step-by-step procedurefor compensating the sensor. calibrate the new sensor in a temperature-controlled environmental chamber. ev kit software an unused serial port on the host pc is required toallow software control of the max1455 ev board. the max1455 ev kit software is an executable file developed using national instrument? labview soft- ware. labview application is not required to run the ev kit software. the software is a high-level interface that calls a low-level serial.dll. note: the max1455 software tools can be down- loaded and installed from the maxim website atwww.maxim-ic.com. table 1. i/o connector s3 signals sensorinterface pin signal description 1 out+ positive output sensor 2 in+ top of wheatstone bridge 3 out+ positive output sensor 4 in- bottom of wheatstone bridge 5 out- negative sensor output 6 in- bottom of wheatstone bridge 7 out- negative sensor output 8 in+ top of wheatstone bridge downloaded from: http:///
evaluates: max1455 max1455 ev kit files the software allows editing the contents of the asic?registers and eeprom, as well as observing the effects of changes to the dac on the output. once desired results are obtained, the eeprom can be programmed with the register contents. consult the max1455 reference manual for a more complete description of software operation and usage. below is a listing of the main files included in the ev kit software tools. max1455 ev kit files max1455 evaluation kit 6 _______________________________________________________________________________________ table 2. i/o connector p1 signal digitalinterface pin signal description 1 gnd ground return (screen) 2 vddin switched +5v return from serial board 3 vddout switched +5v out to serial board 4 gnd ground return (screen) 5 +5v 5v power input 6 gnd ground return 7 +5v 5v power input 8 gnd ground return 9 di/o serial digital communications 10 gnd ground return file function max1455.exe communication program comp55.exe compensation program read.me optional file containing last-minute additions serial.dll low-level functional routines port98nt.exe device driver for pc io communication downloaded from: http:///
evaluates: max1455 max1455 evaluation kit _______________________________________________________________________________________ 7 max1455 test1 u1 c3 1 f c2 0.1 f c51 f r1 10 r24.7k r3 10 j1 out bypass j3 dio to out d1 (not fitted) tp1 1 out tp2 2 inp tp3 3 bdr tp4 4 inm tp5 5 v ss tp6 sp1 s1 68 7 1 s2 10 4 11 6 12 5 sp2sp3 sp5 d2 sp4 6 v dd1 tp7 7 amp+ test2test3 test4 dio unlock v dd2 amp- ampout tp8 tp16tp15 tp14 tp13 tp12 tp11 tp10 tp9 12 3 4 5 6 7 8 9 10 scrnvddin vddout scrn +5v gnd +5v gnd dio gnd 8 1615 14 13 12 11 10 9 inp s3 dip-8 1 bdr 2 inp 3 gnd 4 87 6 5 bdr inm gnd inm c60.1 f j4 vdd tp17 p2p3 p4 4mm_conn4mm_conn 4mm_conn c1470 f +5v out gnd tp18 tp19 10w_header2 p1 j2unlock c4 0.1 f r430 figure 2. max1455 ev kit schematic diagram downloaded from: http:///
evaluates: max1455 max1455 evaluation kit 8 _______________________________________________________________________________________ figure 3. max1455 ev kit top silk figure 4. max1455 ev kit?ottom silkscreen figure 5. max1455 ev kit?op copper figure 6. max1455 ev kit?ottom copper downloaded from: http:///
evaluates: max1455 max1455 evaluation kit _______________________________________________________________________________________ 9 max4490auk u1 12 3 4 5 6 7 8 9 7 u3-a 54hc00 3 12 u3-c u2-c q2-bnds8958 ka d1 bat54 ka 4 4 2 3 5 1 52 13 54hc00 54hc04 8 5 4 35 6 13 9 6 u2-b 54hc04 3 4 u2-d 54hc04 9 8 u2-f 54hc04 12 1 u2-a 54hc04 2 10 u3-d 54hc00 11 1213 u3-b 54hc00 6 45 810 14 13 12 cd rd td -dtr gnd dsr -rts cts 2 15 23 6 2120 19 18 17 16 22 p2 9wayd 9 12 3 4 5 6 7 8 9 scrnvdd out vddin scrn +5v gnd +5v gnd dio gnd p1 10w_header 10 24 11 u2-e 54hc04 10 1 u4 max3387e 3 11 4 5c5 q1-bnds8958 4 35 6 q2-ands8958 2 871 q1-ands8958 q3un5214 q4xp2401 j1 j4j3 2 871 zvn4106f g d q7 d2 s j2 3 rl2he 20 7nd 14 2 23 41 q5un5214 q6un5214 rl1he 20 7nd figure 7. MAX1452KEY adapter schematic diagram downloaded from: http:///
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. 10 ____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2008 maxim integrated products is a registered trademark of maxim integrated products, inc. evaluates: max1455 max1455 evaluation kit max1455 evaluation kit figure 8. adapter circuit pwb?op silkscreen figure 9. adapter circuit pwb?op copper figure 10. adapter circuit pwb?ottom copper downloaded from: http:///
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