STMicroelectronics EVALSTPM3X-3PH

Overview

EVALSTPM3X-3PH from STMicroelectronics is a 3-phase electricity metering evaluation board based on the STPM32/33/34 ASSP family, designed for high-accuracy active/reactive/apparent energy measurement in revenue-grade AC wattmeters. It supports Rogowski coil, current transformer, and shunt-based current sensing; delivers <0.1% active power error over 5000:1 dynamic range; and integrates four 24-bit sigma-delta ADCs, dual programmable-gain low-noise amplifiers, and UART/SPI interfaces - enabling full-system calibration and real-time waveform analysis in smart meter reference designs.

For engineers reviewing the EVALSTPM3X-3PH datasheet, EVALSTPM3X-3PH pinout, EVALSTPM3X-3PH application, or EVALSTPM3X-3PH equivalent, this board provides validated hardware for evaluating STPM3x metrology performance under EN 50470-x, IEC 62053-2x, and ANSI C12.20 compliance conditions - including voltage/current RMS, zero-crossing detection, sag/swell monitoring, and dual-channel SD bitstream output.

Technical Context

The EVALSTPM3X-3PH implements a complete 3-phase metering signal chain using STPM3x ASSPs (STPM32/33/34), each integrating up to four independent 24-bit 2nd-order sigma-delta ADCs with 4 MHz oversampling frequency and 3.6 kHz –3 dB bandwidth. The board routes primary/secondary voltage and current inputs to dedicated chopper-stabilized PGLNAs with gain settings of 2×–16× and input ranges of ±37.5 mV to ±300 mV.

Digital processing includes hardwired DSP for active/reactive/apparent energy calculation, phase compensation filters, decimation (1/512 ratio), and dual serial interfaces (SPI and UART) with programmable CRC. On-board references include two 1.18 V bandgap sources with 30 ppm/°C TC and independent temperature compensation, plus internal 3.0 V and 1.2 V LDOs powering analog/digital sections separately.

Key Specifications

Availability

EVALSTPM3X-3PH is available at Aetrix Electronics and suitable for smart meter development, utility-grade energy monitoring systems, and industrial power quality analyzers requiring stable component supply, traceable calibration validation, and compliance-ready reference hardware.

Supply support for EVALSTPM3X-3PH includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader specializing in microcontrollers, power management, sensors, and analog/mixed-signal ICs - with over 40 years of expertise in industrial and automotive-grade solutions.

The STPM3x product line was developed specifically for revenue-class electricity metering applications, integrating metrology-grade analog front-ends and hardened digital signal processing to replace discrete ADC + MCU implementations in single-chip, low-BOM-cost meters.

FAQ

What is the purpose of the EVALSTPM3X-3PH evaluation board?

The EVALSTPM3X-3PH is a fully assembled and tested 3-phase metering evaluation platform for STMicroelectronics' STPM32/33/34 ASSPs. It enables rapid validation of metrology performance-including active/reactive energy accuracy, RMS voltage/current, zero-crossing detection, and harmonic analysis-under real-world grid conditions (50/60 Hz, sag/swell, overcurrent) and supports compliance testing per IEC 62053-22 and EN 50470-3.

Which STPM3x devices are supported, and how is selection configured?

The board supports STPM32 (QFN24), STPM33 (QFN32), and STPM34 (QFN32) via hardware jumpers that route power, reference, and interface signals to match each device's pinout and functional capabilities. STPM34 enables dual-channel simultaneous measurement (primary + secondary) with four independent ADCs; STPM32 supports single-channel 3-phase operation with two ADCs. Configuration is documented in UM2471.

Does the board provide calibrated measurement outputs out-of-the-box?

No factory calibration is preloaded; however, the board includes all necessary precision external components (e.g., 0.1% resistors, 50 ppm/°C dividers, 150 pF NP0 capacitors) and supports one-point digital calibration across the full dynamic range via SPI/UART. Calibration coefficients (gain, offset, phase) are stored in internal non-volatile registers and applied in real time by the on-chip DSP.

Can the EVALSTPM3X-3PH be used for both shunt- and CT-based current sensing?

Yes - the board provides configurable input paths for shunt (differential mV-level), current transformer (mV-level with burden resistor), and Rogowski coil (integrator-compatible) current sensors. Input scaling resistors and filtering networks are optimized for each method, and the STPM3x PGLNAs support gain settings from 2× to 16× to accommodate ±37.5 mV to ±300 mV input ranges without external op-amps.