High-resolution converter rejects 50/60 Hz noise

Chandler, Ariz. — Microchip Technology Inc. expanded its low-power, high-resolution delta-sigma analog-to-digital (A/D) converter family with what it claims is one of the lowest power, smallest A/D converters available at 22-bit resolution.

Microchip's MCP3550 is available in an 8-pin MSOP package (3.1 x 3.1 x 1.18 mm) and offers low-current operation of 120 microamperes, typical. It rejects noise in either the 50 or 60 Hz line frequencies, resulting in highly accurate measurements for consumer, industrial, battery-powered and portable devices, said Trent Butcher, senior product marketing engineer with Microchip's Analog and Interface Products Division. “Our customers are challenged to design smaller and smaller devices that use fewer components, while providing highly accurate measurements and longer battery life,” he said.

The MCP3550 A/D converter features integral nonlinearity (INL) of ±2 ppm typical, power consumption of 0.6 milliwatts maximum at 5 volts, and output noise as low as 2.5 microvolts rms. The device rejects 50 or 60 Hz noise greater than 120 dB, which makes its measurements impervious to noise from power supplies in these line frequencies, according to Butcher

See related block diagram

The MCP3550-50 (50-Hz rejection) has a sample rate of 12.5 samples per second (sps), and the MCP3550-60 (60-Hz rejection) has a sample rate of 15 sps. Both versions of the A/D converter offer auto calibration with every conversion, and an extended temperature range of -40°C to +125°C.

The new A/D converter targets a variety of applications, including: industrial (instrumentation, pressure sensors, weigh scales, handheld meters and multimeters); medical (heart-rate monitors and blood-glucose meters); consumer (weigh scales and handheld meters); and automotive (sensor interfaces).

The MCP3551 delta-sigma A/D converter PICtail demonstration board (MCP3551DM-PCTL) is available for $40.00.

The MCP3550-50/60 devices are available today. Pricing is $3.20 each for the 8-pin SOIC package, and $3.23 each for the 8-pin MSOP — both in 10,000-piece quantities. Click here for the MCP3550-50/60 data sheets.

Microchip Technology Inc. , 1-888-628-6247,

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