The MAX1497/MAX1499 low-power, 3.5- and 4.5-digit, analog-to-digital converters (ADCs) with integrated lightemitting diode (LED) 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 multiplexed LED display driver. An internal charge pump generates the negative supply needed to power the integrated input buffers for single-supply operation. The ADC is configurable for either a ±2V or ±200mV input range and it outputs its conversion results to an LED and/or to a microcontroller (µC). Microcontroller communication is possible through an SPI™-/QSPI™- /MICROWIRE™-compatible serial interface. The MAX1497 is a 3.5-digit (±1999 count) device and the MAX1499 is a 4.5-digit (±19,999 count) device. The MAX1497/MAX1499 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 rejection of 50Hz and 60Hz line noise. Other features include data hold and peak detection, overrange and underrange detection, and a user-programmable low-battery monitor. The MAX1499 is available in a 32-pin, 7mm x 7mm TQFP package and the MAX1497 is available in 28-pin SSOP and 28-pin PDIP packages. All devices in this family operate over the -40°C to +85°C extended temperature range. Applications * Digital Multimeters * Digital Panel Meters * Digital Voltmeters * Handheld meters * High Resolution * MAX1499: 4.5 Digits (±19,999 Count) * MAX1497: 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 (Exclude LED Driver Current) * Maximum 664µA Operating Current * Maximum 268µA Shutdown Current * Small 32-Pin, 7mm x 7mm TQFP Package (4.5 Digits), 28-Pin SSOP Package (3.5 Digits) * Also Available in a PDIP Package (3.5 Digits) * Multiplexed LED Drivers Resistor-Programmable Segment Current * SPI-/QSPI-/MICROWIRE-Compatible Serial Interface * Extended Temperature Range (-40°C to +85°C)