STPM32TR - 2-Channel Metering AFE, 4x 24-bit Sigma-Delta ADC | STMicroelectronics
MPN: STPM32TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.8 | $38.00 |
| 100 | $3.4 | $340.00 |
| 500 | $3.05 | $1,525.00 |
| 1,000 | $2.75 | $2,750.00 |
| 3,000 | $2.45 | $7,350.00 |
STPM32TR Overview
A metering IC (or meter IC) is a specialized mixed-signal ASSP that combines analog front-end signal conditioning, ADC conversion, and digital computation in a single device to measure electrical parameters such as active, reactive, and apparent power, RMS voltage, RMS current, and energy consumption. Within the broader taxonomy, the STPM32TR sits at the intersection of power management ICs (PMIC) and data converters, serving the smart-grid and billing-meter market segment where IEC 62053 family compliance is mandatory.
Key features of the STPM32TR include four 24-bit sigma-delta ADCs providing 0.5 percent accuracy over a 1:1000 dynamic range when paired with shunt or current-transformer (CT) sensors, on-chip PGLNAs eliminating external op-amps for current channels, integrated digital signal processing for instantaneous active/reactive/apparent power calculation, and a SPI/UART digital interface for host MCU communication. The ADC supports both Rogowski coil and CT or shunt current-sensing transducers, enabling flexible sensor selection.
Architecturally, the STPM32TR uses synchronous sampling on both voltage and current channels, with the modulator oversampling clock feeding a hardware DSP block that computes power line-by-line at every cycle. The integrated PGLNA stages adapt gain across the dynamic range, providing 1:1000 dynamic range without saturation in high-current transient conditions.
Typical applications include single-phase and dual-phase residential smart electricity meters, energy-monitoring sub-metering modules, solar inverter DC-side monitoring, EV charging-station metering front-ends, and industrial power-quality analyzers. The 24-QFN package and operating temperature range of -40C to +85C make the part suitable for compact sealed meter housings.
A critical design consideration when using the STPM32TR is the anti-aliasing filter on each input channel - typically a first-order RC network with cutoff near 10 kHz for 50/60 Hz line frequencies. Designers should also implement glitch detection on the neutral channel when the meter must detect tamper events, and validate the DC-bias calibration routine against the chosen CT or shunt current sensor.
This page synthesizes distributor stock and price data, drop-in alternative parts, and application-level design notes that are not consolidated on the manufacturer datasheet alone.
Drop-in alternatives for STPM32TR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with STPM32TR (same form factor and footprint) — differing in Package, Product Type, ADC Resolution, Mounting Type, ADC Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
STPM33TR
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View Datasheet →STPM34TR
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View Datasheet →STPM32TR Maximum Ratings & Electrical Characteristics
| Product Type | Energy metering AFE (ASSP) |
| Number of ADCs | 4 independent 24-bit sigma-delta |
| ADC Resolution | 24-bit |
| ADC Architecture | 2nd order sigma-delta |
| Output Sample Frequency | 4 MHz OSF (Output Sampling Frequency) |
| Integrated Amplifiers | 2 PGLNA (embedded Programmable Gain LNA) |
| Number of Phases Measured | 2 x single phase (or 1 polyphase) |
| Current Sensor Support | Rogowski coil, CT, or shunt |
| Measurement Accuracy | 0.5% over 1:1000 dynamic range |
| Calculated Parameters | Active / reactive / apparent power, RMS V & I, energy |
| Host Interface | SPI / UART |
| Supply Voltage | 3.3 V typical (see datasheet) |
| Operating Temperature | -40 C to +85 C |
| Package | 24-pin QFN (4x4 mm) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant (Tape & Reel suffix TR) |
| Metering Standards Family | IEC 62053-21 / 62053-22 / 62053-23 (typical conformance) |
| Family Members | STPM32, STPM33, STPM34 |
STPM32TR Pin Configuration
| Pin 1 | [DATA_NEEDED] — Pin assignment must be confirmed against the STMicroelectronics STPM32 datasheet |
| Pin 2 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 3 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 4 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 5 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 6 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 7 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 8 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 9 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 10 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 11 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 12 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 13 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 14 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 15 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 16 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 17 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 18 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 19 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 20 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 21 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 22 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 23 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
| Pin 24 | [DATA_NEEDED] — Pin assignment must be confirmed against the manufacturer datasheet |
Typical Applications
STPM32TR is suitable for 6 applications: Single-Phase Smart Electricity Meter, Dual Single-Phase Sub-Metering Module, Solar Inverter DC-Side Monitoring, EV Charging Station Metering Front-End, Industrial Power Quality Analyzer, Smart Power Strip / PDU Branch Metering.
Single-Phase Smart Electricity Meter
The STPM32TR's four independent 24-bit sigma-delta ADCs and two embedded PGLNAs make it well suited to single-phase residential smart meters where 0.5% accuracy over a 1:1000 dynamic range is required for IEC 62053-22 billing compliance. The ADC channels digitize the line voltage and load current from a CT or shunt sensor at 4 MHz OSF, and on-chip DSP computes active, reactive, and apparent power plus energy registers every line cycle. The host MCU reads these values via SPI/UART to drive the meter's display and push data to the AMI concentrator over PLC or RF.
Recommended
Dual Single-Phase Sub-Metering Module
The STPM32TR can serve two independent single-phase meters in one IC because it has four sigma-delta ADCs, allowing simultaneous voltage-plus-current sensing on two separate load circuits. This makes it attractive for multi-tenant sub-metering or industrial feeder monitoring where a single AFE replaces two discrete meter ICs, reducing BOM cost and PCB area. The PGLNAs adapt to differing CT ratios on each channel, preserving 0.5% accuracy across both loads.
Recommended
Solar Inverter DC-Side Monitoring
Solar inverters monitor DC string or battery current to log energy yield and detect faults, and the STPM32TR's sigma-delta ADCs support Rogowski-coil current sensing for high-side battery or PV string monitoring. The 0.5% accuracy and 1:1000 dynamic range accommodate the wide load range of intermittent solar generation - from micro-amp idle current to peak string current. Energy-counting registers can be reported via SPI to the inverter's control MCU for yield logging and fault shutdown.
Recommended
EV Charging Station Metering Front-End
EV charging stations must meter kWh delivered to the vehicle for billing, and the STPM32TR's IEC 62053-21 accuracy class output and tamper-detection ADC inputs provide the required billing-grade energy measurement plus bypass-tamper evidence. The 24-QFN footprint and -40C to +85C operating range let it integrate into compact sealed AC EVSE enclosures. The host MCU pushes metering records to the OCPP back-end over LTE or Ethernet using the STPM32's SPI output stream.
Recommended
Industrial Power Quality Analyzer
Three-channel monitoring of harmonics, RMS voltage, and RMS current in industrial analyzers benefits from the STPM32TR's four sigma-delta ADCs and on-chip DSP calculation. The 4 MHz OSF oversamples the line enough to capture harmonic content up to about 1 kHz directly, while the host MCU performs additional FFT analysis using the raw ADC stream. The PGLNAs maintain dynamic range across dirty industrial loads.
Recommended
Smart Power Strip / PDU Branch Metering
Networked PDU branch-monitoring outlets meter each output's kWh for data-center load accounting, and the STPM32TR is well suited because four ADCs cover two outlet pairs per IC. The integrated PGLNAs accept Rogowski coils that fit within a 1U PDU chassis, eliminating bulkier CT cores. Energy registers are SPI-readable to a parent MCU that publishes per-outlet data over Ethernet.
Recommended
Recommended Products Summary
Engineering reference data for STPM32TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STPM33TR | STPM34TR | ATM90E32AS-YU-R | CS5490-ISZ |
|---|---|---|---|---|---|
| Package | 24-pin QFN (4x4 mm) | 24-QFN family (verify pinout) | 24-QFN family (verify pinout) | 32-QFN (not drop-in) | 20-SSOP (not drop-in) |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | Microchip Technology | Cirrus Logic |
| Number of ADCs | 4 (24-bit sigma-delta) | 4 (24-bit sigma-delta) | 4 (24-bit sigma-delta) | 3 metering channels | 2 channels (V+I) |
| Integrated PGLNA | Yes, 2 embedded | Yes, 2 embedded | Yes, 2 embedded | Yes (integrated PGA) | No (external AFE required) |
| Current Sensor Support | Rogowski, CT, shunt | Rogowski, CT, shunt | Rogowski, CT, shunt | CT, shunt (Rogowski optional) | CT, shunt |
| Host Interface | SPI / UART | SPI / UART | SPI / UART | SPI (isolated) | SPI |
Key Differentiators
- Four independent 24-bit sigma-delta ADCs with embedded PGLNAs (vs CS5490-ISZ)
- Single-IC support for two single-phase meters (vs CS5490-ISZ)
- Rogowski, CT, and shunt sensor support (vs ATM90E32AS-YU-R)
Design Notes
Estimated: place the anti-aliasing RC network (typically a 1 kohm - 10 kohm resistor and a 1 nF - 10 nF X7R capacitor) within 5 mm of each ADC input pin to prevent conducted noise from aliasing into the measurement band. The 24-QFN backpad must be soldered to a contiguous ground plane and multiple thermal vias for thermal dissipation and return-path integrity.
The CT or Rogowski coil sensing lines are differential and must be routed as matched-length pairs on adjacent layers to preserve the 0.5% accuracy. Keep digital SPI/UART traces away from the analog ADC inputs and use a guarded ground pour to minimize digital-noise coupling into the front-end. Reference the STMicroelectronics STPM32 application note for an example board layout.
Do not assume STPM33 / STPM34 are drop-in pin-compatible with the STPM32TR - they are family siblings but pinout and register differences exist and must be verified against the datasheet before substituting. Cross-brand alternatives (CS5490, ATM90E32AS) require PCB respin because the package differs.
The STPM32TR operates on a low-voltage supply (3.3 V typical) and must be powered from a low-noise LDO fed by the meter's auxiliary supply. A switching regulator placed on the same board can introduce common-mode noise that degrades the ADC SNR unless followed by an LC filter or isolator before reaching the AFE supply pin.
Compliance Information
RoHS compliance inferred from the TR (Tape & Reel) suffix and STMicroelectronics product family marking. AEC-Q100 not applicable (consumer/industrial metering IC). IEC 62053 family compliance depends on end-product calibration, not on the AFE alone.
