Optoisolator Targets PLC’s 24-V Inputs, Hits 10 Mb/s

Toshiba’s TLP2363 high-speed, standard-footprint optocoupler targets the 24-V digital-input needs of PLCs and industrial devices, while providing galvanic isolation to 3750 Vrms.

Bill Schweber

Jan. 31, 2020

2 min read

Optoisolators—also called optocouplers or photoisolators—are widely used to provide galvanic (ohmic) isolation of digital-signal inputs and outputs in industrial environments, as well as in other applications. The Toshiba TLP2363 is a high-speed (10 Mb/s) logic-level output photocoupler for the 24-V digital inputs often associated with programmable logic controller (PLCs) and other measurement and control equipment.

The device requires a supply current of just 4 mA and a threshold input current (I^FHL) of 0.3 mA (minimum) and 2.4 mA (maximum) to ensure conformance to the digital input standard IEC 61131-2 type 1. The short propagation delay of just 80 ns is commensurate with high-speed systems and data rates.

Although isolation voltage rating is partially a function of physical size and thus internal input/output physical separation as well as package-pin creepage and clearance, the TLP2363 offers a minimum isolation-voltage rating of 3750 V_rms. This despite being housed in a small, thin SO6 package with five actual pins (pin 2 is absent) and with a maximum height of 2.3 mm. By using the common six-pin optocoupler footprint, it can be a drop-in replacement for existing optocouplers from many vendors (see figure).

The pinout and footprint of the Toshiba TLP2363 10-Mb/s optocoupler is the same as most industry-standard devices, but it also offers support for 24-V inputs of PLCs (and other industrial applications) along with a 3750-Vrms isolation-voltage rating.

The TLP2363, which meets a long list of relevant regulatory standards, incorporates an internal Faraday shield to guarantee common-mode transient immunity of ±20 kV/µs and is rated for a wide operating temperature range of−40 to +105°C). The detailed, 18-page datasheet offers numerous min/max/typical values for key parameters as well as graphs defining performance across a range of factors.