Unboxing Smart Embedded display starter kit +++ TOLL housing 27 % smaller than D²PAK +++ Photo relay with 5 KV insulation voltage

Reliable contact despite "contactless transfer":
Photo relay with 5 KV insulation voltage

TLP4590A und TLP4590AF photo relays from TOSHIBA

The TOSHIBA TLP4590A and TLP4590AF photo relays contain a photo MOSFET optically coupled to an infrared light emitting diode.

These devices replace mechanical relays in applications to save space and increase reliability.

The TLP4590 replicates a single-pole normally closed (SPST-NC, 1-form-B, normally closed) MOSFET relay.

The majority of the photo relays are single-pole normally open contacts - normally opened (SPST-NO,1-Form-A). Both variants can be used to convert changeover contacts and other relay circuits into more robust solid-state relay technology.


photo relays - contact closed

Contact closed:
Both athletes are connected via the baton

photo relays - contact opened

Contact opened:
There is no contact between the athletes


SPST NO = Single Pole, Single Throw, Normally Open - Single pole switch with normally open contact.

SPST NC = Single Pole, Single Throw, Normally Close - Single pole switch with normally closed contact


Current-carrying capacity and dielectric strength

With a dielectric strength of up to 60 V, this solid-state relay covers most of the industrial voltage range (12 V / 24 V / 36 V). The power MOSFETs in Com. source circuit (A-connection) can switch off direct or alternating currents of 1.2 A @ 25°C. Pulsed currents of up to 3 A are possible. Pulsed up to 3 A. When both MOSFETs are connected in parallel (C-connection) for pure DC operation, the current-carrying capacity increases up to 2.4 A.

Temperature and insulation voltage

The coupler supports a wide temperature range from -40 °C to 110 °C.

Coupled with an insulation voltage strength of 5 kV(min), or 5000 V (min), it ensures safe isolation between the control and operating circuits under the most adverse operating conditions. Approvals include UL 1577 and VDE EN60747-5-5.

Areas of application

Major applications for this photo relay include building automation - including heating, ventilation, air conditioning (HVAC) and security systems, as well as fire alarm systems. They can also be used in various forms of industrial equipment, such as programmable logic controllers (PLC/PLC), I/O interfaces and sensor control hardware and metering applications.

Low LED trigger current

The TLP4590 has a much higher current carrying capacity, higher insulation voltage and TOPR than, for example, market competitor IXYS with its LCB710. It is available in THT and SMT versions with different lead forming (bending of the legs).

The 6 advantages of MOSFET-based solid state relays:

  1. No contact bounce
  2. No mechanical wear
  3. No arcing when switching on and off
  4. Silent switching
  5. Low switching delay
  6. Magnetically neutral: Are neither disturbed by magnetic fields nor do they emit any.

Solid-state relays increase the reliability (service life) of your customer application, installation space is drastically reduced. They can be controlled directly via a GP I/O port of a µC. This saves components such as free-wheeling diodes and small-signal transistors. Clacking of the contact pieces and wear are eliminated. Photo relays can be easily assembled by machine. Due to the low mass m, they are also less sensitive to vibrations and g-forces.

Further information on TOSHIBA solid-state relays is available on request:

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