This document is the technical specification of SAMES SA9903B single phase bi-directional energy/power metering integrated circuit. The chip can measure active power, reactive power, mains voltage and mains frequency. It meets the IEC 521/1036 standard.
The SA9903B is a CMOS mixed‑signal integrated circuit that measures active and reactive power, RMS voltage and mains frequency for single‑phase applications. It provides bi‑directional energy measurement via a SPI interface and stores results in four 24‑bit registers.
The device is offered in DIP‑20 and SOIC‑20 packages, operates from ±2.5 V supplies, consumes less than 25 mW, and meets IEC Class 1 watt‑hour and VAR‑hour specifications. Detailed pin descriptions, electrical characteristics, and typical application circuits are included.
| Operating temperature range | -25 °C to +85 °C |
|---|---|
| Positive supply voltage (Voo) | 2.25 V – 2.75 V |
| Negative supply voltage (Vos) | -2.75 V – -2.25 V |
| Positive supply current | 3.56 mA – 5 mA |
| Negative supply current | 3.56 mA – 5.1 mA |
| Power consumption | < 25 mW |
| Oscillator crystal frequency | 3.5795 MHz |
The SA9903B contains four 24‑bit registers that store active energy, reactive energy, RMS voltage and mains frequency.
A serial peripheral interface (SPI) bus is used; the device acts as a slave and provides data through the DO, DI, CS and SCK pins.
The absolute maximum supply voltage rating is –0.3 V to +6.0 V.
Yes, all inputs and outputs are protected against ESD.