Overview
The STPM34TR, produced by STMicroelectronics, is an Application-Specific Standard Product (ASSP) designed for high accuracy measurement of power and energies in power line systems. This IC is part of the STPM3x family, which is optimized for use with Rogowski coils, current transformers, or shunt current sensors. The STPM34TR provides instantaneous voltage and current waveforms and calculates RMS values of voltage and currents, active, reactive, and apparent power, and energies.
The device integrates both analog and digital sections. The analog section includes up to four independent 24-bit 2nd order sigma-delta ADCs and two programmable gain low-noise low-offset amplifiers. The digital section features a digital filtering stage, a hardwired DSP, and a serial communication interface (UART or SPI).
Key Specifications
| Parameter | Specification |
|---|---|
| ADC Resolution | Up to four independent 24-bit 2nd order sigma-delta ADCs |
| Amplifiers | Two programmable gain low-noise low-offset amplifiers |
| Voltage References | Twin precision voltage reference: 1.18 V with independent programmable TC, 30 ppm/°C typ. |
| Supply Voltage | 3.3 V ± 10% |
| Supply Current | 4.3 mA (STPM32) |
| Input Clock Frequency | 16 MHz, Xtal or external source |
| Operating Temperature | -40 °C to +105 °C |
| Package | VFQFPN 32 5x5x1.0 mm |
| Bandwidth | 3.6 kHz at -3 dB |
Key Features
- Active power accuracy: < 0.1% error over 5000 : 1 dynamic range, < 0.5% error over 10000 : 1 dynamic range
- 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
- Internal low drop regulator at 3 V (typ.)
Applications
The STPM34TR is primarily designed for smart metering and smart grid applications. It is suitable for:
- Single-phase and dual-phase energy metering systems
- Industrial power monitoring and control systems
- Smart grid infrastructure
- High accuracy power and energy measurement in various electrical systems
Q & A
- What is the primary function of the STPM34TR?
The STPM34TR is designed for high accuracy measurement of power and energies in power line systems.
- What types of sensors can the STPM34TR work with?
The STPM34TR can work with Rogowski coils, current transformers, or shunt current sensors.
- What is the resolution of the ADCs in the STPM34TR?
The STPM34TR includes up to four independent 24-bit 2nd order sigma-delta ADCs.
- What are the key features of the analog section of the STPM34TR?
The analog section includes up to four independent 24-bit 2nd order sigma-delta ADCs and two programmable gain low-noise low-offset amplifiers.
- What is the operating temperature range of the STPM34TR?
The operating temperature range is from -40 °C to +105 °C.
- What communication interfaces are available on the STPM34TR?
The STPM34TR features UART and SPI serial interfaces with programmable CRC polynomial verification.
- Does the STPM34TR support voltage and current monitoring?
Yes, it provides instantaneous and averaged power, RMS and instantaneous voltage and current, and under/overvoltage detection.
- What is the typical supply current of the STPM34TR?
The typical supply current is 4.3 mA (for the STPM32 model).
- What are the key applications of the STPM34TR?
The STPM34TR is used in smart metering, smart grid applications, and industrial power monitoring and control systems.
- Is the STPM34TR compliant with industry standards for AC watt meters?
Yes, it exceeds the requirements of standards such as EN 50470-x, IEC 62053-2x, and ANSI 12.2x for AC watt meters.
