ST0945 AC-Type 4.5~5.5V Low-Power Residual Current Device (RCD) IC
Specifications
Product details
Overview
The ST0945 is a high-performance dedicated integrated circuit for AC-type residual current protection, detecting AC-type residual current signals on live and neutral lines. It integrates a regulated power supply, amplifier circuit, comparator circuit, delay circuit, trip control circuit and SCR driver circuit; combined with an external tripping coil and power supply circuit, it implements a complete RCD solution. When leakage occurs, the residual current signal is detected through a zero-sequence current transformer (ZCT) whose secondary winding output serves as the IC input; once the RMS value of the residual current exceeds the RCD rating, the OUT pin generates an active level with a pulse width greater than 20ms, driving the SCR into operation. With a positive trip voltage of 4~7mV (VDD=5V) and a typical quiescent current of only 260µA, the trip delay can be flexibly adjusted via an external capacitor on the DLY pin, and only simple resistors and capacitors are needed for a typical application. Offered in a SOP-8L package over a -40~+85℃ operating range, the ST0945 provides a highly consistent AC-type residual current protection solution for low-voltage distribution, home appliances and industrial control equipment.
Features
- Detects AC-type residual current signals
- OUT outputs a pulse width greater than 20ms upon detection and can directly drive the SCR
- Consistent tripping accuracy for residual current signals
- Excellent electromagnetic interference (EMI) immunity
- Suitable for 110V~220V (50Hz~60Hz) supply voltage
- Adjustable trip delay (external capacitor on DLY; 9~15ms with 330nF)
- Low quiescent current: typ 260µA (VDD=5V)
- Positive trip voltage 4~7mV (VDD=5V); output latch time 20~50ms
- SOP-8L package, -40~+85℃ operating temperature
Typical Applications
- Low-voltage distribution equipment
- Home appliances
- Industrial control equipment
