low power, 3 1 M 2 digit a/d converter with display hold max136 typical operating circuit pin configurations general description the max136 is a monolithic analog-to-digital converter (adc) with very high input impedance. it differs from the maxim icl7136 in that the max136 provides a hold pin, which makes it possible to hold or "freeze" a reading. the max136 directly drives a nonmultiplexed liquid crystal (lcd) display, requiring no external drive circuitry. with minor external component changes, it is pin compatible with the icl7116 but with significantly reduced power consumption, making the max136 a superior device for portable systems. versatility and accuracy are inherent features of this adc. the dual-slope conversion technique automatically rejects interference signals common in industrial envi - ronments. true differential inputs allow direct measure - ments of bridge transducer outputs or load cells. the zero-integrator phase eliminates overrange hangover and hysteresis effects. the max136 offers high accuracy by lowering rollover error to less than one count and zero reading drift to less than 1v/c. applications these devices can be used in a wide range of digital panel meter applications. most applications, however, involve the measurement and display of analog data: features ? power dissipation guaranteed less than 1mwC9v battery life 3000 hours typical ? hold pin allows indefinite display hold ? guaranteed first reading recovery from overrange ? on-board display drive capabilityno external circuitry required ? high-impedance cmos differential inputs ? low noise(< 15v p-p ) without hysteresis or overrange hangover ? clock and reference on-chip ? zero input gives zero reading ? true polarity indication for precision null applications ? key parameters guaranteed over temperature ordering information + denotes a lead(pb)-free/rohs-compliant package. pressure voltage resistance temperature conductance current speed material thickness pin configurations continued at end of data sheet (detailed circuit diagram?see 3rd page) max136 analog input 9v v ref to analogcommon (p32) lcd display part temp range pin-package max136cpl+ 0c to +70c 40 pdip max136cmh+ 0c to +70c 44 mqfp max136cqh+ 0c to +70c 44 plcc max136c/d 0c to +70c dice for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim integrated?s website at www.maximintegrated.com. 19-0890; rev 1; 11/12 downloaded from: http:///
2 maxim integrated low power, 3 1 M 2 digit a/d converter with display hold max136 supply voltage (v+ to v-) ..................................................... 15v analog input voltage (either input) (note 1) .................. v+ to v- reference input voltage (either input) ........................... v+ to v- clock input, hold input ............................................. test to v+ power dissipation (note 2) pdip ............................................................................. 800mw operating temperature range ............................. 0c to +70c storage temperature ....................................... -65c to +160c lead temperature (soldering, 60s) ................................ +300c absolute maximum ratings note 1: input voltages may exceed the supply voltages, provided the input current is limited to 1ma. note 2: dissipation rating assumes device is mounted with all leads soldered to printed circuit board. downloaded from: http:///
3 maxim integrated low power, 3 1 M 2 digit a/d converter with display hold max136 detailed description the max136 3? digit adc is similar to the maxim icl7136 except for the addition of a hold pin. for a detailed product description, and applications informa - tio n (other than the operation of the hold pin described below), refer to maxim's icl7136 data sheet. hold input the hold input is a digital input with a logic thresh - old approximately midway between v+ and test. the max136 continuously performs conversions, indepen - dent of the hold input. when the hold input is at v+ the display latch pulse is inhibited, and the display latches are not updated; when the hold input is low or at the test voltage, the display is updated at the end of each conversion. the max136 maintains low-power dissipa - tion even during display hold by eliminating the pulldown resistor between hold and test present on the icl7116. the hold input is cmos compatible, and can also be driven by a switch connected between test and v+ (figure 1). reference input unlike the icl7136, the max136 does not have a refer - ence low input. apply the reference voltage between reference high (ref hi) and figure 1. max136 typical operating circuit, 200mv full scale figure 2. max136 typical operating circuit, 2.0v full scale max136 analog input 9v v ref to analogcommon (p32) lcd display backplanedrive segmentdrive 0.47f c ref osc 2 r osc c osc osc 3 osc c ref 0.47f 0.0f 0.047f m i 0 i 0 i 0 i 00 i 3 34 33 20 2 minus sign run old 373 3 2 in i 29 222 pdl bp test old ref i v v in locommon buff a int 3032 2 29 39 3 40 0f 27 max136 analog input 9v v ref to analogcommon (p32) lcd display backplanedrive segmentdrive 0.47f c ref osc 2 r osc c osc osc 3 osc c ref 0.47f 0.0f 0.047f m i 0 i 0 i 0 i 00 i 3 34 33 20 2 minus sign run old 373 3 2 in i 29 222 pdl bp test old ref i v v in locommon buff a int 3032 2 29 39 3 40 0f 27 downloaded from: http:///
4 maxim integrated low power, 3 1 M 2 digit a/d converter with display hold max136 package information for the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages . note that a ?+?, ?#?, or ?-? in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. pin configurations (continued) part type package code document no. land pattern no. 40 pdip p40+1 21-0044 ? 44 plcc q44+1 21-0049 90-0236 44 mqfp m44+5 21-0826 90-0169 441234 40 41 42 43 5 21 24 26 25 27 28 22 23 19 20 8 9 1011 12 13 14 15 16 17 29 30 31 32 33 34 35 36 37 38 d3 e3 b1 plcc top view c1d1 hold n.c. osc1 osc2 osc3 test ref hi f3 pol ab4 bp n.c. a3 g3g2 c3 c + ref c - ref common in hin.c. in lo a/z buff int v ? e2 f2 a2 b2 n.c. c2 d2 e1 g1 7 39 v + f1 6 18 a1 b3 max136 n.c.g2(tens) c3 a3 g3 bp pol(-) ab4 e3 f3 b3 n.c.n.c. test osc3 n.c. osc2osc1 hold d1c1 b1 12 3 4 5 6 7 8 9 1011 1213 14 15 16 17 18 19 20 21 22 4443 42 41 40 39 38 37 36 35 34 3332 31 30 29 28 27 26 25 24 23 a1 f1 g1 e1 d2c2 b2a2 f2e2 d3 ref hiv + c + ref c - ref commoninhi inlo a/z buff int v - mqfp max136 downloaded from: http:///
maxim integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim integrated product. no circuit patent licenses are implied. maxim integrated reserves the right to change the circuitry and specifications without notice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. maxim integrated 160 rio robles, san jose, ca 95134 usa 1-408-601-1000 5 ? 2012 maxim integrated products, inc. maxim integrated and the maxim integrated logo are trademarks of maxim integrated products, inc. low power, 3 1 M 2 digit a/d converter with display hold max136 revision history revision number revision date description pages changed 0 2/87 initial release ? 1 11/12 add mqfp package to ordering information and package information . 1, 4 downloaded from: http:///
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