Datasheet

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Low Power, 3

⁄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 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:

Features

• PowerDissipationGuaranteedLessthan1mW–9V

BatteryLife3000HoursTypical

• 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(<15µV

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

REF

TO ANALOG

COMMON (P32)

LCD DISPLAY

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

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

Summary of content (5 pages)

PAGE 1
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.
PAGE 2
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..............................................................................
PAGE 3
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.
PAGE 4
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.
PAGE 5
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.