Energy-measurement IC combines low power, SPI interface

Chandler, Ariz. — Microchip Technology Inc. has released its MCP3909 energy-measurement IC and reference design for a variety of single- and three-phase industrial and consumer energy meters. The highly accurate IC combines low-power consumption with a SPI interface and active power pulse output, making it adaptable to a wide variety of meter designs.

The MCP3909 IC features two on-board 16-bit delta-sigma analog-to-digital converters (ADCs) that can be accessed through its SPI interface, while simultaneously providing a pulse output with a frequency proportional to the active-power calculation. This simultaneous output of data makes the IC flexible and easy to use, as well as adaptable to a variety of meter requirements, according to the company.

In addition, with its very low 0.1% typical measurement error over a 1000:1 dynamic range, the MCP3909 IC easily fits into meter applications requiring high accuracy, and the low supply current of 4 mA makes it suitable for many single- and three-phase energy meter designs.

The MCP3909 3-Phase Energy Meter Reference Design (Part # MCP3909RD-3PH1) includes three MCP3909 ICs, a PIC18F2520 microcontroller for power calculations and a PIC18F4550 microcontroller, which provides a USB interface to desktop software. The software package enables meter calibration and the ability to read active and apparent power, as well as RMS current and RMS voltage.

Pricing: The MCP3909 IC is available in a 24-pin SSOP package and can be purchased at for $1.51 each in quantities of 10,000.
Availability: Samples can be ordered at The reference design is expected to be available for purchase in March 2007 at at a price of $175 each.
Additional resources:

Microchip Technology , 1-480-792-7200,

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