TLP185(GB-TPLSE(T

The TLP185(GB-TPLSE(T from Toshiba is a general-purpose photocoupler consisting of a gallium arsenide infrared LED optically coupled to a phototransistor detector in a compact SOP4 surface-mount package. With a minimum current transfer ratio (CTR) of 50% at 5 mA forward current and 3750 Vrms isolation voltage, it provides reliable electrical isolation between input and output circuits. The device is UL1577 and VDE 0884 approved for safety-critical isolation applications. The SOP4 package offers significant board space savings compared to DIP packages while maintaining creepage and clearance requirements.

The TLP185 operates by converting electrical signals to light and back. When forward current flows through the infrared LED on the input side, it emits infrared radiation that passes through the optically transparent isolation barrier and strikes the base region of the phototransistor on the output side. The absorbed photons generate base current in the phototransistor, which is amplified by the transistor’s current gain (hFE) to produce a collector current. The current transfer ratio (CTR) is the ratio of output collector current to input LED current, specified at a minimum of 50% at IF=5mA. The internal isolation barrier provides galvanic separation rated at 3750 Vrms between input and output.

• Signal isolation in industrial control and PLC systems
• Switch-mode power supply feedback loop isolation
• Appliance and white goods control signal isolation
• Motor drive logic-to-power interface isolation
• Medical equipment patient interface isolation