TLP388 Transistor Output Photocouplers Toshiba TLP388 Transistor Output Photocouplers are optically coupled to InGaAs infrared emitting diodes. These TLP388 photocouplers are housed in a thin 4-pin SO6L package. The TLP388 photocouplers offer 350V high breakdown voltage between the collector to the emitter (VCEO). These photocouplers operate at -55ºC to 125ºC temperature range. The TLP388 transistor output photocouplers are suitable for Programmable Logic Controllers (PLCs), air conditioner inverters, and home appliances.