MAX136CMH+TD

MAX136 Low Power, 31⁄2 Digit A/D Converter with Display Hold General Description Features 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. • Power Dissipation Guaranteed Less than 1mW–9V Battery Life 3000 Hours Typical Versatility and accuracy are inherent features of this ADC. The dual-slope conversion technique automatically rejects interference signals common in industrial environments. True differential inputs allow direct measurements 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 1µV/°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: Pressure Voltage Resistance Temperature Conductance Current Speed Material Thickness • Hold Pin Allows Indefinite Display Hold • Guaranteed First Reading Recovery from Overrange • On-Board Display Drive Capability—No External Circuitry Required • High-Impedance CMOS Differential Inputs • Low Noise(< 15µVP-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 PART TEMP RANGE PIN-PACKAGE MAX136CPL+ 0°C to +70°C 40 PDIP MAX136CMH+ 0°C to +70°C 44 MQFP MAX136CQH+ 0°C to +70°C 44 PLCC MAX136C/D 0°C to +70°C Dice +Denotes a lead(Pb)-free/RoHS-compliant package. Pin Configurations Typical Operating Circuit LCD DISPLAY ANALOG INPUT MAX136 9V VREF TO ANALOG COMMON (P32) (Detailed Circuit Diagram—See 3rd page) Pin Configurations continued at end of data sheet 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 MAX136 Low Power, 31⁄2 Digit A/D Converter with Display Hold ABSOLUTE MAXIMUM RATINGS Supply Voltage (V+ to V-)......................................................15V Analog Input Voltage (either input) (Note 1)...................V+ to VReference Input Voltage (either input)............................V+ to VClock Input, Hold Input..............................................TEST to V+ Power Dissipation (Note 2) PDIP..............................................................................800mW Operating Temperature Range.............................. 0°C to +70°C Storage Temperature........................................ -65°C to +160°C Lead Temperature (soldering, 60s).................................+300°C 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. 2   Maxim Integrated MAX136 Low Power, 31⁄2 Digit A/D Converter with Display Hold Detailed Description The MAX136 3½ digit ADC is similar to the Maxim ICL7136 except for the addition of a Hold pin. For a detailed product description, and applications information (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 threshold approximately midway between V+ and Test. The MAX136 continuously performs conversions, independent 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 dissipation 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 reference low input. Apply the reference voltage between Reference High (REF HI) and 0.47µF 0.47µF 34 33 LCD DISPLAY C+ REF C- REF 2-19 SEGMENT 22-25 DRIVE 31 IN HI PDL 20 BACKPLANE BP 21 MINUS SIGN DRIVE 30 TEST 37 RUN IN LO 1 32 HOLD COMMON HOLD 35 28 V+ BUFF 1MI ANALOG INPUT 0.01µF 180kI 0.47µF 29 0.047µF 27 A/Z REF HI INT VREF 36 OSC2 OSC3 OSC1 38 COSC 40 100kI TO ANALOG COMMON (P32) 0.047µF 0.47µF 29 27 150kI MAX136 A/Z VREF 36 REF HI INT 9V 100kI 26 V- OSC2 OSC3 OSC1 38 COSC 40 39 TO ANALOG COMMON (P32) ROSC ROSC 50pF 180kI Figure 1. MAX136 Typical Operating Circuit, 200mV Full Scale Maxim Integrated 0.01µF 9V 26 V- 39 ANALOG INPUT 180kI 150kI MAX136 1MI 34 33 LCD DISPLAY C+ REF C- REF 2-19 SEGMENT 22-25 DRIVE 31 IN HI PDL 20 BACKPLANE BP 21 MINUS SIGN DRIVE 37 30 TEST RUN IN LO 1 32 HOLD COMMON HOLD 35 28 V+ BUFF 50pF 180kI Figure 2. MAX136 Typical Operating Circuit, 2.0V Full Scale   3 MAX136 Low Power, 31⁄2 Digit A/D Converter with Display Hold Pin Configurations (continued) C2 11 35 IN HI N.C. 12 B2 13 A2 MAX136 34 N.C. 33 IN LO 32 A/Z 14 31 BUFF E2 16 30 INT D3 17 29 V− G2 C3 A3 G3 BP N.C. AB4 POL 19 20 21 22 23 24 25 26 27 28 E3 18 F3 15 B3 F2 34 35 36 37 38 39 40 41 3 31 4 30 5 29 MAX136 6 28 7 27 8 26 9 25 10 24 11 23 N.C. G2(TENS) C3 A3 G3 BP POL(-) AB4 E3 F3 B3 22 36 COMMON 21 10 20 D2 32 19 37 C-REF 33 2 18 9 1 17 E1 N.C. N.C. TEST OSC3 N.C. OSC2 OSC1 HOLD D1 C1 B1 16 38 C+REF 15 8 14 G1 42 REF HI V+ C+REF C-REF COMMON INHI INLO A/Z BUFF INT V39 V+ 12 7 A1 F1 G1 E1 D2 C2 B2 A2 F2 E2 D3 F1 43 44 44 43 42 41 40 13 1 REF HI 2 TEST N.C. 3 OSC3 HOLD 4 OSC2 D1 5 OSC1 B1 6 C1 A1 TOP VIEW PLCC MQFP 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. PART TYPE 4   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 Maxim Integrated MAX136 Low Power, 31⁄2 Digit A/D Converter with Display Hold Revision History REVISION NUMBER REVISION DATE DESCRIPTION 0 2/87 Initial release 1 11/12 Add MQFP package to Ordering Information and Package Information. PAGES CHANGED — 1, 4 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 ©  2012 Maxim Integrated Products, Inc. 5 Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.