ST0940 Single 3.3V 10mW Built-in Clock Calibration-Free Single-Phase Energy Metering IC

ST0940 Single 3.3V 10mW Built-in Clock Calibration-Free Single-Phase Energy Metering IC

ST0940

The ST0940 is a built-in clock calibration-free energy metering IC integrating two independent Sigma-Delta ADCs (one for current, one for voltage), a voltage reference, power management and digital signal processing circuits. It measures RMS current/voltage, active power and active energy over a current range of 10mA~35A @ 1mΩ and an active energy range of 1W~7700W @ 1mΩ @ 220V. The IC provides fast current RMS output for over-current protection, temperature detection and waveform output, plus current-voltage waveform phase angle and voltage zero-crossing signal outputs; the integrated temperature sensor supports over-temperature monitoring, preset temperature alarms for high-current nodes and ambient temperature measurement. Factory gain error is below 1% per batch, and no calibration is required when external discrete components meet specified conditions; data is delivered via UART/SPI interfaces. Operating from a single 3.3V supply at 10mW typical in a TSSOP14 package, the ST0940 is widely used in single-phase multifunction energy meters, smart sockets, smart home appliances, e-bike charging stations and large-scale power consumption data collection.

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Specifications

MeasurementBuilt-in clock calibration-free single-phase energy metering: RMS current/voltage, active power/energy, fast current RMS (over-current protection), temperature detection, waveform output, phase angle; current 10mA~35A@1mΩ, energy 1W~7700W@1mΩ@220V
Power Consumption10 mW (typ, single 3.3V)
ADC Channels2 independent Sigma-Delta ADCs (one current, one voltage)
OutputUART/SPI (data) + voltage zero-crossing signal output
ClockBuilt-in oscillator, approx. 4 MHz
VDDSingle 3.3V
CalibrationFactory gain error <1% per batch
FreeCalibration-free when external discrete components meet specified conditions
PackageTSSOP14

Product details

Overview

The ST0940 is a built-in clock calibration-free energy metering IC suited for single-phase multifunction energy meters, smart sockets, smart home appliances, e-bike charging stations and other applications, offering high cost-effectiveness. It integrates two high-precision Sigma-Delta ADCs, a reference voltage, power management and other analog circuit modules, along with digital signal processing circuits for computing active power, RMS current/voltage and other electrical parameters. The ST0940 measures current RMS, voltage RMS, active power, active energy and other parameters, and provides fast current RMS output for over-current protection, temperature detection and waveform output. Data is delivered via UART/SPI interfaces, fully meeting the requirements of smart sockets, smart home appliances, single-phase multifunction energy meters, e-bike charging stations and large-scale power consumption data collection. Its patented anti-creep design, combined with appropriate external hardware, ensures noise power is not accumulated into energy pulses when no current is present. Factory gain error is below 1% per batch, and calibration is unnecessary when external discrete components meet specified conditions.

Features

  • Two independent Sigma-Delta ADCs, one for current and one for voltage
  • Current RMS range 10mA~35A @ 1mΩ
  • Active energy range 1W~7700W @ 1mΩ @ 220V
  • Outputs current/voltage RMS, fast current RMS, active power and current-voltage waveform phase angle
  • Factory gain error <1% per batch; calibration-free when external components meet specified conditions
  • Current channel over-current monitoring with configurable threshold and response time
  • Voltage zero-crossing signal output
  • Built-in waveform registers outputting waveform data for load type analysis
  • Integrated temperature sensor for over-temperature monitoring, preset high-current node temperature alarm and ambient temperature measurement
  • Integrated SPI (max 900kHz) / UART (4800bps) communication
  • Power-down detection with chip reset below 2.7V; built-in 1.218V reference voltage source
  • Built-in oscillator circuit, clock approx. 4MHz
  • Single 3.3V supply, 10mW typical power consumption; TSSOP14 package

Typical Applications

  • Single-phase multifunction energy meters
  • Smart sockets
  • Smart home appliances
  • E-bike charging stations
  • Large-scale power consumption data collection

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