5000Vrms isolation — dual-channel signal transfer across a safety barrier
The HCPL2531TSR2VM is a dual-channel optocoupler from onsemi with a transistor output stage, rated for 5000Vrms isolation between input and output. This isolation rating suits applications requiring galvanic separation for safety or noise immunity — think PLC digital inputs, motor-drive feedback paths, or medical equipment where the barrier must withstand high-voltage transients without breakdown. Each channel drives up to 8 mA at a maximum output voltage of 20 V, with a current transfer ratio (CTR) ranging from 19% to 50% at a forward current of 16 mA. The CTR spread means the output side can sink enough current to drive a logic gate input or a small relay coil directly, but the minimum 19% figure sets the load-driving margin — if the downstream input requires 2 mA, the LED side must supply at least 10.5 mA to guarantee the output turns on across all units.
250 ns switching — fast enough for isolated serial data up to 2 MHz
Typical turn-on time is 250 ns, turn-off 260 ns, giving a combined propagation delay around 500 ns. This supports isolated data rates up to roughly 2 MHz — adequate for isolating SPI clock lines, encoder pulse trains, or low-speed fieldbus signals like RS-485 at 1 Mbps. For faster protocols like 10 Mbps Ethernet or high-speed CAN, a digital isolator with CMOS outputs would be a better fit. The input is DC-coupled with a maximum forward current of 25 mA and a typical forward voltage of 1.45 V. The 8-SMD Gull Wing package (supplier device package 8-SMD) is a standard surface-mount footprint compatible with reflow soldering; the Gull Wing leads provide visual solder-joint inspection access.
onsemi lists the HCPL2531TSR2VM as Active with no discontinuation notice. For a spare-parts storeroom or a production line, this means the part is still in the manufacturer's standard portfolio and can be ordered through authorized distribution without last-time-buy urgency.