Rainbow Electronics MAX1495 - Manual

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 (±1999 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, crystal
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 continu-
ous 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 calibration
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
Features
♦ High Resolution
MAX1495: 4.5 Digits (±19,999 Count)
MAX1493: 4.5 Digits (±19,999 Count)
MAX1491: 3.5 Digits (±1999 Count)
♦ Sigma-Delta ADC Architecture
No Integrating Capacitors Required
No Autozeroing Capacitors Required
>100dB of Simultaneous 50Hz and 60Hz Rejection
♦ Operate from a Single 2.7V or 5.25V Supply
♦ Selectable Input Range of ±200mV or ±2V
♦ Selectable Voltage Reference: Internal 2.048V or
External
♦ Internal High-Accuracy Oscillator Needs No
External Components
♦ Automatic Offset Calibration
♦ Low Power: Maximum 980µA Operating Current
♦ 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)
♦ Triplexed LCD Driver
♦ Evaluation Kit Available (Order MAX1494EVKIT)
MAX1491/MAX1493/MAX1495
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
DV
DD
INTREF V
NEG
DPON GND BP1 BP2 BP3
10 13 15 14 16 11 12 9
DPSET2
HOLD PEAK SEG2 SEG1 SEG4 SEG3 SEG5
17
18
19
20
21
22
23 SEG12
24 SEG13
SEG11
SEG10
SEG9
SEG8
SEG7
SEG6
2
3
4
5
6
7
8 DPSET1
RANGE
LOWBATT
REF+
REF-
AIN-
AIN+
1 AV DD
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 2; 5/04
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