The MAX1491/MAX1493/MAX1495 low-power, 3.5- and
4.5-digit, analog-to-digital converters (ADCs) with integrated
liquid crystal display (LCD) drivers operate from a
single 2.7V to 5.25V power supply. They include an internal
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 configurable
for either a ±2V or ±200mV input range and it outputs
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 external-
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 continuous
internal offset calibration, and offer >100dB rejection
of 50Hz and 60Hz line noise. The MAX1493/
MAX1495 perform enhanced offset calibration at powerup.
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 family
operate over the 0°C to +70°C commercial temperature
range.