The TOSHIBA TLP521−1, −2 and −4 consist of a photo−transistor
optically coupled to a gallium arsenide infrared emitting diode.
The TLP521−2 offers two isolated channels in an eight lead plastic DIP
package, while the TLP521−4 provides four isolated channels in a
sixteen plastic DIP package.

Collector−emitter voltage: 55 V (min)
Current transfer ratio: 50% (min)
Rank GB: 100% (min)
Isolation voltage: 2500 Vrms (min)
UL recognized

made in Japan: UL1577, file No. E67349
made in Thailand: UL1577, file No. E152349