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AFE features high sample rates, multiple metering apps

A next-generation Analog Front End (AFE) for metering applications has arrived. The MCP3901 AFE features high-accuracy, dual 16-/24-bit Delta-Sigma Analog-to-Digital Converters (ADCs) with up to 91 dB Signal to Noise and Distortion (SINAD); internal Programmable Gain Amplifiers (PGAs) and voltage reference; phase-delay compensation; and a modulator output block, enabling more precise measurements than competitive solutions. With its unique feature set, high-speed sample rates up to 64 kilosamples per second (ksps) and SPI interface, the MCP3901 AFE is ideal for a variety of single- and multi-phase metering, industrial and medical applications.

Integrated PGAs and a low-drift voltage reference enhance the MCP3901 AFE’s ability to measure signals at very small levels, and reduce the number of external components needed. This enables smaller overall designs at lower costs. The phase-delay compensation block enables the MCP3901 AFE to compensate for differences in phase for three-phase energy-metering applications, while the SPI interface provides a simple connection to a microcontroller (MCU) and offers engineers more flexibility with their design. Additionally, through the SPI interface, designers can adjust the ADC oversampling ratio to control the resolution and sample rate as dictated by the needs of the application.

Example applications for the MCP3901 AFE include utility meters (e.g. single and multi-phase electricity meters); industrial (e.g. power monitoring and instrumentation); and medical applications (e.g. blood glucose meters, pulse oximeters).

Microchip also announced today the MCP3901 Evaluation Board (part # MCP3901EV-MCU16, $80), which enables access to the MCP3901 through various test points, and to a computer through a serial interface. Via user-interface software on their computers, engineers can view the performance of the MCP3901 AFE using various analysis parameters such as SINAD, Effective Number of Bits (ENOB), Total Harmonic Distortion (THD), and Signal-to-Noise Ratio (SNR). The evaluation board can be purchased online, at

For additional design support, visit Microchip's online Utility Meter Design Center ( This site provides engineers technical tools and resources needed to create accurate, reliable and low-cost utility metering applications, including energy, water, and gas and heat meters.

The MCP3901 AFE is available in a 20-pin SSOP package, for $1.42 each in 10,000-unit quantities. Samples can be ordered at, and the device can purchased at

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