12-Bit, 20Msps, +3.3V, Low-Power ADC with Internal Reference

The MAX1422 3.3V, 12-bit analog-to-digital converter (ADC) features a fully differential input, pipelined, 12- stage ADC architecture with wideband track-and-hold (T/H) and digital error correction incorporating a fully-differential signal path. The MAX1422 is optimized for lowpower, high dynamic performance applications in imaging and digital communications. The converter operates from a single 3.3V supply, consuming only 137mW while delivering a 67dB (typ) signal-to-noise ratio (SNR) at a 5MHz input frequency and a 20Msps sampling frequency. The fully-differential input stage has a small signal -3dB bandwidth of 400MHz and may be operated with single-ended inputs.

An internal 2.048V precision bandgap reference sets the ADCs full-scale range. A flexible reference structure accommodates an internally or externally applied buffered or unbuffered reference for applications requiring increased accuracy or a different input voltage range.

In addition to low operating power, the MAX1422 features two power-down modes, a reference power-down, and a shutdown mode. In reference power-down, the internal bandgap reference is deactivated, resulting in a 2mA (typ) supply current reduction. For idle periods, a full shutdown mode is available to maximize power savings.

The MAX1422 provides parallel, offset binary, CMOS-compatible three-state outputs.

The MAX1422 is available in a 7mm x 7mm x 1.4mm, 48-pin TQFP package and is specified over the commercial (0°C to +70°C) and extended industrial (-40°C to +85°C) temperature ranges.

Pin-compatible higher-speed versions of the MAX1422 are also available. Please refer to the MAX1421 data sheet for 40Msps and the MAX1420 data sheet for 60Msps.

Applications

* CCD Pixel Processing * Data Acquisition * IF and Baseband Digitization * Medical Ultrasound Imaging * Radar

* Single 3.3V Power Supply

* 67dB SNR at fIN = 5MHz

* Internal 2.048V Precision Bandgap Reference

* Differential Wideband Input T/H Amplifier

* Power-Down Modes

* 130mW (Reference Shutdown Mode)

* 10µW (Shutdown Mode)

* Space-Saving 48-Pin TQFP Package