General Description

The MAX1491/MAX1493/MAX1495 low-power, 3.5- and

4.5-digit, analog-to-digital converters (ADCs) with inte-

grated liquid crystal display (LCD) drivers operate from a

single 2.7V to 5.25V power supply. They include an inter-

nal reference, a high-accuracy on-chip oscillator, and a

triplexed LCD driver. An internal charge pump generates

the negative supply needed to power the integrated input

buffer for single supply operation. The ADC is config-

urable for either a ±2V or ±200mV input range and it out-

puts its conversion results to an LCD. The MAX1491 is a

3.5-digit (±1,999 count) device, and the MAX1493/

MAX1495 are 4.5-digit (±19,999 count) devices.

The MAX1491/MAX1493/MAX1495 do not require exter-

nal-precision integrating or auto-zero capacitors, crys-

tal oscillators, charge pumps or other circuitry required

with dual slope ADCs (commonly used in panel meter

circuits). These devices also feature on-chip buffers for

the differential signal and reference inputs, allowing

direct interface with high-impedance signal sources. In

addition, the MAX1491/MAX1493/MAX1495 use contin-

uous internal offset calibration, and offer >100dB rejec-

tion of 50Hz and 60Hz line noise. The MAX1493/

MAX1495 perform enhanced offset calibration at

power-up. The MAX1495 also performs enhanced cali-

bration on demand. Other features include data hold

and peak hold, and a user programmable low-battery

monitor.

TQFP package, and the MAX1491 comes in 28-pin

SSOP and 28-pin DIP packages. All devices in this fam-

ily operate over the 0°C to +70°C commercial tempera-

ture range.

Applications

Digital Panel Meters

Hand-Held Meters

Digital Voltmeters

Digital Multimeters

Features

o High Resolution

MAX1495: 4.5 Digits (±19,999 Count)

MAX1493: 4.5 Digits (±19,999 Count)

MAX1491: 3.5 Digits (±1999 Count)

o Sigma-Delta ADC Architecture

No Integrating Capacitors Required

No Autozeroing Capacitors Required

>100dB of Simultaneous 50Hz and 60Hz Rejection

o Operate from a Single 2.7V or 5.25V Supply

o Selectable Input Range of ±200mV or ±2V

o Selectable Voltage Reference: Internal 2.048V or

External

o Internal High-Accuracy Oscillator Needs No

External Components

o Automatic Offset Calibration

o Low Power: Maximum 980µA Operating Current

Digits), 28-Pin SSOP Package (3.5 Digits), and 28-

Pin DIP Package (3.5 Digits)

o Triplexed LCD Driver

o Evaluation Kit Available (Order MAX1494EVKIT)

3.5- and 4.5-Digit, Single-Chip

ADCs with LCD Drivers

________________________________________________________________ Maxim Integrated Products

1

TOP VIEW

MAX1493

MAX1495

TQFP

32

28

29

30

31

25

26

27

10

13

15

14

16

11

12

9

17

18

19

20

21

22

SEG11

SEG10

SEG9

SEG8

SEG7

SEG6

2

3

4

5

6

7

8

DPSET1

RANGE

LOWBATT

REF+

REF-

AIN-

AIN+

1

PART

TEMP

RANGE

PIN-

PACKAGE

RESOLUTION

(DIGITS)

MAX1491CAI*

0

°C to +70°C 28 SSOP

3.5

MAX1491CNI

0

°C to +70°C 28 DIP

3.5

MAX1493CCJ

0

°C to +70°C 32 TQFP

4.5

MAX1495CCJ*

0

°C to +70°C 32 TQFP

4.5

Pin Configurations

Ordering Information

19-3053; Rev 0; 10/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Pin Configurations continued at end of data sheet.

EVALUATION

KIT

AVAILABLE

*Future product—contact factory for availability.