Optocoupler for isolated signal transfer in harsh environments
The Toshiba TLP183(BL-TPL,E is a single-channel DC-input transistor-output optocoupler rated for 3750Vrms isolation, housed in a compact 6-SOP package. It delivers a current transfer ratio (CTR) ranging from 200% to 600% at a forward current of 5 mA, with a maximum Vce saturation of 300 mV. The output transistor can switch up to 80 V and 50 mA per channel.
The CTR bin of 200% to 600% at 5 mA forward current gives the designer a wide margin for LED drive current selection. A minimum CTR of 200% means the output transistor can saturate with as little as 2.5 mA input drive, useful for low-power microcontroller I/O pins. On the high end, 600% CTR at the same forward current allows the optocoupler to drive a logic input directly without a buffer stage. Typical turn-on and turn-off times are both 3 µs, with rise and fall times of 2 µs and 3 µs respectively — fast enough for 100 kHz switching in isolated gate drives or feedback loops, but not for high-speed data above 1 Mbps.
The 6-SOIC package with 4 leads (0.173" body width, 4.40 mm) is a common footprint shared with other Toshiba TLP183 family variants and the TLP185 series. The surface-mount package saves board area compared to DIP-4 optocouplers while maintaining 3750Vrms isolation through the internal optical path.