MAX1494

The MAX1492/MAX1494 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 outputs its conversion results to an LCD and/or to a microcontroller (µC). µC communication is facilitated through an SPI™-/QSPI™-/MICROWIRE™-compatible serial interface. The MAX1492 is a 3.5-digit (±1999 count) device, and the MAX1494 is a 4.5-digit (±19,999 count) device.

The MAX1492/MAX1494 do not require external-precision integrating capacitors, autozero 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, they use continuous internal-offset calibration and offer >100dB simultaneous rejection of 50Hz and 60Hz line noise. Other features include data hold and peak hold, overrange and underrange detection, and a lowbattery monitor.

The MAX1494 comes in a 32-pin, 7mm x 7mm TQFP package, and the MAX1492 comes in 28-pin SSOP and 28-pin PDIP packages. All devices in this family operate over the 0°C to +70°C commercial temperature range.