Toshiba releases photocouplers for speed-challenged applications

Photocouplers use light emitters and receivers along with a light-transmissive insulator to provide a high degree of electrical insulation in a small package. They have a wide range of applications, with one of the most popular being programmable logic controllers (PLCs), which are essential for automating modern factories.

For correct operation, photocouplers require input signals to have a minimum rise time to avoid undesirable switching at the output. The four new photocouplers (TLP2362B, TLP2368B, TLP2762B, TLP2768B) comply with IEC 61131-2 (Type 1) and provide hysteresis for the input forward current threshold and the power supply circuit, making them suitable for use in high EMC noise environments.

Providing hysteresis within the device ensures that the output will maintain its ‘high’ or ‘low’ state without additional switching. Built-in hysteresis eliminates the need for external circuitry (such as Schmitt triggers) and reduces complexity and cost.

Demanding applications such as PLCs require photocouplers with data transmission rates that exceed the typical levels of a few kbps. The four new photocouplers incorporate a high-gain, high-speed amplifier, allowing the TLP2362B and TLP2762B to support 10Mbps and the TLP2368B and TLP2768B to support 20Mbps. This enables faster communication in end applications.

All devices deliver an output current (Io) of 25mA and can tolerate input rise and fall times as long as 60s. Operation remains unaffected provided the supply voltage (VCC) is established within 60s.

The TLP2368B and TLP2768B achieve a propagation delay of less than 60ns. The TLP2362B and TLP2368B are housed in a 5-pin SO6 package measuring 3.7 x 7.0 x 2.3mm with an isolation voltage (BVs) that exceeds 3,750Vrms. The TLP2762B and TLP2768B are housed in a SO6L package (3.84 x 10.0 x 2.3mm) and are rated for BVs greater than 5,000Vrms.

All four of the new photocouplers are capable of operating at ambient temperatures as high as 125°C (and as low as -40°C), ensuring that end applications such as PLCs operate reliably in all conditions.

Mass production of all four new photocouplers is now underway.