MAX1491 Datasheet, PDF (1/25 Pages) Maxim Integrated Products – 3.5- and 4.5-Digit, Single-Chip ADCs with LCD Drivers

19-3053; Rev 0; 10/03
EVAALVUAAILTAIOBNLEKIT
3.5- and 4.5-Digit, Single-Chip
ADCs with LCD Drivers
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.
The MAX1493/MAX1495 come in a 32-pin 7mm ✕ 7mm
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
Ordering Information
PART
TEMP
RANGE
PIN-
RESOLUTION
PACKAGE
(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
*Future product—contact factory for availability.
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
o Small 32-Pin 7mm ✕ 7mm TQFP Package (4.5
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)
Pin Configurations
TOP VIEW
AV_DD 1
AIN+ 2
AIN- 3
REF- 4
REF+ 5
LOWBATT 6
RANGE 7
DPSET1 8
32 31 30 29 28 27 26 25
MAX1493
MAX1495
24 SEG13
23 SEG12
22 SEG11
21 SEG10
20 SEG9
19 SEG8
18 SEG7
17 SEG6
9 10 11 12 13 14 15 16
TQFP
Pin Configurations continued at end of data sheet.
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