16-bit converters optimized for precision measurement apps

Bettyann Liotta

eeProductCenter (04/06/2005 3:11 PM ET)

Dallas — Extending its delta-sigma data converters offering, Texas Instruments Inc. (TI) today introduced a pair of high-speed, high-precision analog-to-digital converters (A/D converters) for very linear high-speed operation, and demanding measurement applications in scientific instrumentation, automated test equipment, data acquisition, medical imaging and vibration analysis.

The modulator within the ADS1602 A/D converter samples input signals with a 40-MHz clock, while the digital filter decimates the modulator output by 16 to provide high-resolution 16-bit output data at 2.5 Msamples/s over a serial interface. Dynamic performance is strong all the way up to the 1.23 MHz-passband transition. Total harmonic distortion (THD) is less than -101 dB; spurious-free dynamic range (SFDR) is greater than 103 dB, while signal-to-noise ratio (SNR) is greater than 91 dB.

The ADS1601 has the same advanced architecture and is intended for applications requiring less aggressive data rates and lower power dissipation. This device features 1.25 Msamples/s data rate, 330 mW power dissipation and high-speed performance: 92 dB SNR, -103 dB THD and 105 dB SFDR. The devices are pin-compatible.

Both converters utilize oversampling topology which reduces clock jitter sensitivity during the sampling of high-frequency, large amplitude signals by a factor of four over that achieved by Nyquist-rate A/D converters. A full-scale 3-V differential input range makes out-of-range signals unlikely.

Power dissipation is set by an external resistor and can be reduced when operating at slower speeds. The devices operate from a +5 V analog supply and a +3 V digital supply. The digital I/O supply operates from +2.7 V to +5.25 V, enabling the digital interface to support a range of logic families. Dedicated I/O pins control all features.

Evaluation modules for both devices are available. The ADS1601 and ADS1602 are packaged in a 7mm x 7mm TQFP-48 and are available now. The ADS1601 is priced at $14 in 1,000- piece quantities, and the ADS1602 is priced at $23 in same quantities.Click here for the ADS1601 data sheet. Click here for the ADS1602 data sheet.

Texas Instruments, 1-800-477-8924, www.TI.com.

Related Stories:

» 16-bit A/D draws half the power at full speed
» ADI rolls out single-chip converters for precise capacitance and impedance measurements