MCU Family Vies For Energy Metering Assignments

Introduced as the industry’s first system-on-a-chip microcontroller unit (MCU) for electronic energy meters, the MSP430FE42x family combines a flash MCU with an analog front-end (AFE), with this level of mixed-signal integration promising to reduce chip counts by up to 80%. Features include an embedded signal processor (ESP), three 16-bit sigma-delta a/d converters operating at 1 MHz, three programmable gain amplifiers, temperature sensor, and a precision voltage reference. Once signals are processed, the chip provides energy and line period measurement, negative power flow indication, peak voltage and current, and phase and line-to-neutral current comparisons. Operating on 3V, power consumption with the CPU and ESP active is 2.5 mA and 1.1 µA in standby with the real-time-clock function active. The family also includes a watchdog timer, LCD driver for up to 128 segments, brownout protection, supply voltage supervisor, three-channel pulse width modulation timer, asynchronous UART or synchronous SPI interfaces, and serial programming. Available with 8, 16, or 32 KB of flash memory and 256 bytes to 1 KB of RAM, the chips come in a 64-pin QFP package, with the 8-KB MSP430FE423 priced at $2.95 each/100,000. TEXAS INSTRUMENTS INC., Dallas, TX. (800) 477-8924.