Four isolated transistor outputs in one SO-16
The Toshiba TLP292-4(GBTPR,E is a quad-channel phototransistor optocoupler in a 16-SOIC package. Each channel provides galvanic isolation rated at 3750 Vrms between the AC/DC input LED and the transistor output, with a minimum current transfer ratio of 100% and a maximum of 600% at a forward current of 5 mA. The output transistor can handle up to 80 V and 50 mA per channel, with a typical Vce saturation of 300 mV. This part is suited for isolating digital or slow analog signals in industrial controls, PLC I/O modules, motor-drive feedback, and power-supply housekeeping where four independent isolation channels are needed in a single surface-mount package.
The 3750 Vrms isolation rating is the one-minute withstand voltage between input and output. For a 240 VAC mains-referenced circuit, this provides basic insulation with margin; for 120 VAC systems it meets reinforced insulation requirements in many IEC 60950-1 and IEC 62368-1 applications. The 80 V output rating per channel means the transistor side can interface directly with 24 V or 48 V logic rails, or with 5 V / 3.3 V MCU inputs through a pull-up resistor.
CTR range: 100% to 600% at 5 mA
The current transfer ratio spans 100% minimum to 600% maximum at a forward current of 5 mA. That wide spread means the designer must account for CTR variation across temperature and lifetime when sizing the input drive and output pull-up. At 100% CTR, 5 mA in gives 5 mA out; at 600% CTR, the same 5 mA in gives up to 30 mA out. For logic-level interfaces, a pull-up resistor that guarantees a valid logic low at minimum CTR will still work at maximum CTR without exceeding the output current rating.