12-Bit, 40Msps, 3.3V, Low-Power ADC with Internal Reference

The MAX1421 is a 3.3V, 12-bit analog-to-digital converter (ADC), featuring 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 MAX1421 is optimized for low-power, high-dynamic performance applications in imaging and digital communications. The converter operates from a single 3.3V supply, consuming only 188mW while delivering a typical signal-to-noise ratio (SNR) of 66dB at an input frequency of 15MHz and a sampling frequency of 40Msps. 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 full-scale range of the ADC. A flexible reference structure accommodates an internal 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 MAX1421 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 typical 2mA supply current reduction. For idle periods, a full shutdown mode is available to maximize power savings.

The MAX1421 provides parallel, offset binary, CMOS-compatible three-state outputs.

The MAX1421 is available in a 7mm x 7mm, 48-pin LQFP package, and is specified over the commercial (0°C to +70°C) and the extended industrial (-40°C to +85°C) temperature ranges.

Pin-compatible higher- and lower-speed versions of the MAX1421 are also available. Please refer to the MAX1420 data sheet for a frequency of 60Msps and the MAX1422 data sheet for a frequency of 20Msps.

Applications

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

* Single 3.3V Power Supply

* 67dB SNR at fIN = 5MHz

* 66dB SNR at fIN = 15MHz

* Internal, 2.048V Precision Bandgap Reference

* Differential, Wideband Input T/H Amplifier

* Power-Down Modes

* 180mW (Reference Shutdown Mode)

* 10µW (Shutdown Mode)

* Space-Saving 48-Pin LQFP Package