Analog Devices' AD7190 delta-sigma converter Dallas TX

Analog Devices' AD7190 delta-sigma converter includes the functions to make a complete precision-measurement front end. In addition to the 24-bit converter, the part features a PGA (programmable-gain amplifier) configurable for gains of one to 128. The device also has an internal multiplexer to provide for two differential-measurement sources or four pseudodifferential sources. It incorporates an internal clock source, a temperature sensor, and a bridge-power-down circuit to allow power savings by deactivating the bridge that the part is measuring. The high-precision converter, which can detect an open-sensor condition, suits use in strain gauges, scales, process measurement, control modules, scientific instrumentation and chromatography instruments, and other high-resolution data-acquisition tasks.

Operating with 3 to 5.25V of power, the AD7190 consumes 6 mA of current; rms noise is 7 nV at a gain of 128. The offset drift is 5 nV/°C, and gain drift is 2 ppm/°C.

The device produces noise-free, 21-bit measurements at 4.7 Hz and 16.5-bit, noise-free measurements at 2.4 kHz, and it performs simultaneous 50- and 60-Hz rejection on an incoming signal. The ADC interfaces to the digital system using an SPI (serial-peripheral interface) or Microwire-compatible interface. You can select a no-latency mode to reduce software overhead if you need a valid conversion per output data. The device also has four general-purpose digital outputs, although two of these outputs also serve as alternative external-reference inputs.

The AD7190 is available in a 24-pin TSSOP for a suggested retail price of $5.90 (1000). It operates over a -40 to +105°C temperature range. Samples are available now, and production quantities will be available in November. An evaluation kit interfaces to a PC with a USB.

Analog Devices, www.analog.com.