A/D Converter Offers DSP Interface

A high-resolution, high data rate, delta-sigma analog-to-digital converter offers 20 bits of resolution and a 25 kHz sample rate, ADS1250 is intended for applications such as industrial process controls, medical analysis, smart transmitters, weight scales, chromotagraphy and portable instrumentation. The ADS1250 consists of a programmable gain amplifier, a fourth-order delta-sigma modulator, a digital filter, control logic, and serial interface for easy connection to mCs and DSPs. The delta-sigma architecture achieves a wide dynamic range and guarantees 20 bits of no missing code performance. Performance of 2.8 ppm of rms noise is achieved through use of a very low noise amplifier at conversion rates up to 25 kHz. Dynamic range is further increased with a low-noise PGA with gain stages of 1, 2, 4 and 8. The device operates from a nominal 5V supply and is guaranteed to consume less than 100 mW. Device includes a flexible synchronous interface and two-wire communications mode for low-cost isolation.