TLP281

The TLP281 is Toshiba's single-channel phototransistor photocoupler, coupling a gallium arsenide infrared emitting diode to a silicon phototransistor in a very small, thin four-pin SOP intended for surface-mount assembly. Toshiba designed it for programmable controllers, AC and DC input modules and PC-card modems, and it has been in continuous production since March 1996. Pin configuration is 1 anode, 2 cathode, 3 emitter, 4 collector — identical to the PC817S and the Everlight EL357N — and the four-channel sibling TLP281-4 provides the same circuit four times in a 16-pin SOP. The package is Toshiba outline 11-3A1 with a typical weight of 0.05 g.

Isolation is rated 2500 Vrms minimum for a 60 second AC test at 60 % relative humidity or less, with 0.8 pF typical input-to-output capacitance and 5 x 10^10 Ω minimum isolation resistance at 500 Vdc. The device is UL 1577 recognized under file E67349, cUL recognized under CSA Component Acceptance Service No. 5A, and VDE approved to EN 60747-5-5 when the option (V4) is specified. Input ratings are 50 mA continuous forward current derated at 0.7 mA/°C above 53 °C, 1 A pulse forward current at 100 µs and 100 pps, 5 V reverse voltage and 100 mW dissipation, with a 1.0 V minimum, 1.15 V typical and 1.3 V maximum forward voltage at IF = 10 mA. Output ratings are 80 V minimum collector-emitter breakdown at IC = 0.5 mA, 7 V emitter-collector breakdown, 50 mA collector current, 150 mW collector dissipation and 200 mW total package dissipation, with dark current of 0.1 µA maximum at VCE = 48 V (50 µA maximum at 85 °C).

Current transfer ratio is specified at IF = 5 mA and VCE = 5 V — the same condition used for PC817 grading — with the blank rank covering 50 % to 600 %, Rank Y 50 % to 150 %, Rank GR 100 % to 300 %, Rank BL 200 % to 600 % and Rank GB 100 % to 600 %, plus the narrower YH, GRL, GRH and BLL sub-bins. Saturated CTR is 60 % typical at IF = 1 mA and VCE = 0.4 V (30 % minimum for Rank GB), and collector-emitter saturation voltage is 0.4 V maximum at IC = 2.4 mA and IF = 8 mA, or 0.2 V typical at IC = 0.2 mA and IF = 1 mA. Switching is quick for this class: 2 µs typical rise, 3 µs typical fall, and 3 µs typical turn-on and turn-off at VCC = 10 V, IC = 2 mA and RL = 100 Ω. Toshiba's own data also shows the storage-time penalty of a large collector resistor — with RL = 1.9 kΩ, VCC = 5 V and IF = 16 mA, turn-off stretches to 40 µs with 25 µs of storage time — so keep the collector load small and the LED drive modest.

As a sourcing matter the TLP281 sits in the PC817 interchangeability group with the Sharp/Socle PC817, Lite-On LTV-817, Everlight EL817 and EL357N, and buyers in Shenzhen routinely cross-ship between them. That convenience carries one caveat: the isolation ratings differ substantially — 2500 Vrms for the TLP281, 3750 Vrms for the EL357N, 5000 Vrms for the PC817 — so a substitution that is fine for signal isolation may invalidate a reinforced-insulation safety case. If you need Toshiba's higher isolation in the same outline, the TLP291 is rated 3750 Vrms minimum with 80 V output and CTR of 50 % to 400 %. Rank GB is the most commonly stocked bin in Asia. Screen incoming lots by measuring CTR at IF = 5 mA and VCE = 5 V, dark current at VCE = 48 V, saturation voltage, and by hipot-testing samples at 2500 Vrms; remarked PC817 clones and re-tinned pulled parts are the usual problems. MOQ is one tape-and-reel; Shenzhen stock ships in 1 to 2 days while factory channel orders run 6 to 10 weeks.