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ASSP for metering applications with up to four independent 24-bit 2nd order sigma-delta ADCs, 4 MHz OSF and 2 embedded PGLNA
  • active Active

The STPM3x is an ASSP family designed for high accuracy measurement of power and energies in power line systems using the Rogowski coil, current transformer or shunt current sensors. The STPM3x provides instantaneous voltage and current waveforms and calculates RMS values of voltage and currents, active, reactive and apparent power and energies. The STPM3x is a mixed signal IC family consisting of an analog and a digital section. The analog section consists of up to two programmable gain low-noise low-offset amplifiers and up to four 2nd order 24-bit sigma-delta ADCs, two bandgap voltage references with independent temperature compensation, a low drop voltage regulator and DC buffers. The digital section consists of digital filtering stage, a hardwired DSP, DFE to the input and a serial communication interface (UART or SPI). The STPM3x is fully configurable and allows a fast digital system calibration in a single point over the entire current dynamic range.

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Errata Sheet
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Key Features

  • Active power accuracy:
  • <0.1% error over 5000: 1 dynamic range
  • <0.5% error over 10000: 1 dynamic range
  • Exceeds 50-60 Hz EN 50470-x, IEC 62053-2x, ANSI12.2x standard requirements for AC watt meters
  • Reactive power accuracy:
  • <0.1% error over 2000:1 dynamic range
  • Dual mode apparent energy calculation
  • Instantaneous and averaged power
  • RMS and instantaneous voltage and current
  • Under and overvoltage detection (sag and swell) and monitoring
  • Overcurrent detection and monitoring
  • UART and SPI serial interface with programmable CRC polynomial verification
  • Programmable LED and interrupt outputs
  • Four independent 24-bit 2nd order sigma-delta ADCs
  • Two programmable gain chopper stabilized low-noise and low-offset amplifiers
  • Bandwidth 3.6 kHz @ -3 dB
  • Vcc supply range 3.3 V ±10%
  • Supply current Icc 4 mA (STPM32)
  • Input clock frequency 16 MHz, Xtal or external source
  • Twin precision voltage reference: 1.18 V with independent programmable TC, 10 ppm/°C typ.
  • Internal low drop regulator @ 3 V (typ.)
  • QFN packages
  • Operating temperature from -40 °C to +85 °C

Design Resources


Technical Documentation

Product Specifications

Description Version Size
DS10272: ASSP for metering applications with up to four independent 24-bit 2nd order sigma-delta ADCs, 4 MHz OSF and 2 embedded PGLNA
3.0 3,650 KB

Application Notes

Description Version Size
AN4470: The STPM3x application calibration
2.0 638 KB

User Manual

Description Version Size
UM1719: The STPM3x evaluation software
1.1 1,324 KB
UM1748: EVALSTPM34, EVALSTPM33, EVALSTPM32 evaluation board
2.0 976 KB

Design Notes & Tips

Description Version Size
DT0039: Improving measuring accuracy and EFT immunity for STPM3x applications
1.0 1,919 KB

Presentations & Training Material


Description Version Size
STPM32, STPM33, STPM34 Smart Metering ICs
825 KB

Related Tools and Software

Related Tools and Software

Part Number Description
EVALSTPM34 Dual-phase energy metering evaluation board with 2 current transformers based on the STPM34
STSW-STPM001 STPM32/33/34 evaluation software
EVALSTPM3X-3PH Poly-phase energy metering demonstration board with current transformers based on the STPM33, STPM34 and STM8S903
STEVAL-IPE023V1 USB interface tool for STPMxx family of energy meter ICs

Publications and Collaterals


Description Version Size
730 KB

Sample & Buy

Part Number Marketing StatusPackagePacking TypeOperating Temperature (min) Operating Temperature (max) AutoshutdownAutomotive GradeOrder From STUnit Price (US$)*
@ 1000
Distributor AvailabilityRoHS Compliance GradeDownload
Material Declaration**
STPM34TRActiveVFQFPN 32 5x5x1.0Tape And Reel-4085_Free Samples.94Distributor reported inventory date: 2016-02-08
Distributor NameRegionStockMin. order
ARROWOrder NowAMERICA29403000
Farnell Element14Order NowEUROPE22571

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors
(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.
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