Making the Impossible Possible by having the features of both mechanical relays and semiconductors.


Semiconductor relay that combines LEDs and
MOS FET chips to realize relay functions

A MOS FET relay is a non-contact relay used primarily for switching and connecting signals. It has mechanical relays and semiconductors features and is used in a semiconductor inspection system, various measurement devices, security equipment, and a wide range of other applications.

[MOS FET relay]Mechanical Relay (Reed Relay), Low ON Resistance, Versatility, High Isolation, Excellent Linearity, Long Life, Compact, Low Noise, Semiconductor Device
[Photocoupler]A photocoupler is a component consisting of a light emitting diode (LED) and a light receiving element. The input electrical signal is converted into an optical signal by the LED, and the light-receiving element converts the optical signal into an electrical signal again to output it. It is mainly used when electrical isolation between the input and output circuits is required in order to reduce noise effects and safety risks. There are three major types of photocouplers, and the primary difference is the type of light-receiving element used. A MOS FET relay is also a type of photocoupler. [Transistor coupler]Light-receiving element, Phototransistor[TRIAC coupler]Light-receiving element, Photo TRIAC [MOS FET relay]Light-receiving element, PDA + MOSFET

MOS FET Relay Cross Section

A MOS FET relay is a semiconductor relay that uses MOS FET as its output element.
The MOS FET relay consists of the following three chips:

MOS FET chip, PDA chip, Lead frame, Wire, LED chip, Silicone resin, Epoxy resin

Principle and Function of MOS FET Relay

①LED emits light when an electric current is applied->②PDA (solar cell) generates electricity->③MOS FET turns ON

Mechanical Relay vs. MOS FET Relay

STRONG POINT ①:Unparalleled compact size contributes to smaller and denser equipment

Compared with mounting area for 10 pieces (mounted at 0.3mm intervals)

(General reed relay)Size: 20mm x 5mm x 5mm, Mounting area: 20mm x (5+0.3) x 10 = 1060mm2(G3VM S-VSON package)Size: 2mm x 1.45mm x 1.65mm, Mounting area: 2mm x (1.45+0.3) x 10 = 35mm2[Mounting area can be reduced by about 65%]

STRONG POINT ②:Long life

Mechanical relay, Reed relay, MOS FET relay[No switching life]

The absence of contact points (i.e., no mechanical life) reduces maintenance frequency for products that use many relays.

STRONG POINT ③:Stable ON resistance

Compared to mechanical relays, the ON resistance of MOS FET relays that have no contacts does not depend on the number of switching cycles.

STRONG POINT ④:Low power consumption

Compared to reed relays, power consumption on the input is very low, contributing to the energy saving of equipment.

Drive Current Comparison* Example of 5VDC drive (Reed relay)(General-purpose MOS FET relay)10%:Compared to reed relays(High-sensitivity MOS FET relay)4%:Compared to reed relays

STRONG POINT ⑤:Other features

Mechanical Relay
(Reed Relay)
Yes Operating noise Silent operation possibleNo mechanical contact
= No contact sound
Yes Contact bouncing NoneNo mechanical contact
= No contact bouncing
RequiredSurge absorber is required to protect peripheral circuits from surges (reverse voltage) generated by the coil Coil surge absorber (input) Not requiredNo coil, thus no surge
(reverse voltage)
220 VDC
Load voltage (peak value) High-voltage type comparable to mechanical relays also available不要G3VM-601DY1
Max. 600 VDC
2000 VAC (1 min.)
Dielectric strength between input and output High-dielectric strength type comparable to mechanical relays also available不要G3VM-601DY1
Max. 5000 VAC
(1 min.)

Semiconductor Device vs. MOS FET Relay

STRONG POINT ①:Excellent linearity

The output elements of transistor couplers and TRIAC couplers have low linearity, resulting in distortion of the signal passing between outputs.
Unlike transistor couplers and TRIAC couplers, MOS FET relays suppress signal distortion due to their excellent linearity characteristics comparable to mechanical relays.
The ability to control analog signals makes it ideal for testers and measuring instruments.

[Load current vs. Load voltage]
[Signal transfer]

STRONG POINT ②:Stable low-current drive contributes to energy saving

MOS FET relay

The output switching current of MOS FET relays is not affected by the input current.
MOS FET relays can operate at very low currents, contributing to power savings in equipment. Even after its lifetime, the output current does not drop as it does with transistor couplers.

Transistor coupler

Transistor couplers consume more power than MOS FET relays because a larger input current also results in a larger output current.
Therefore, more power is consumed because the output is also weakened by LED degradation.

STRONG POINT ③:Low input current controls high output switching current

  Transistor coupler G3VM-61CR1
(MOS FET relay)
LED input current 1 to 10 mA 5 mA
Output switching current 1 to 20 mA Max. 10,000 mA
Connection C

STRONG POINT ④:Ultra-low leakage current

Compared to other semiconductor devices, the leakage current in the off-state is very small, making it possible to measure minute currents. Suppressing unnecessary leakage current contributes to lower heat generation and less circuit malfunctions, which are factors in performance degradation.

  Transistor coupler TRIAC coupler G3VM-41GR8
(MOS FET relay)
Leakage current Approx. 10 uA Approx. 100 nA Max. 1 nA

STRONG POINT ⑤:Full range of variations for both AC and DC

Variations available for both AC and DC expand the range of applications.

Transistor coupler TRIAC coupler MOS FET relay
DC only
AC only
Supporting AC or DC

STRONG POINT ⑥:Low heat generation

Low heat generation due to low on-resistance
No heat sinks or other components to dissipate heat are required.

MOS FET Relay Lineup

Package Types

DIP: Assuming the mounting area as 100%, SOP: Mounting area 62%, SSOP: Mounting area 24%, USOP: Mounting area 20%, P-SON: Mounting area 16%, VSON (R): Mounting area 10%, VSON: Mounting area 9%, S-VSON: Mounting area 8% * 84% for VSON

MOS FET Relay Model Standard

MOS FET Relay Packaging Types

Product Map

OMRON offers a wide range of MOS FET relays so that you can select the right product for your application.
For a selection of MOS FET relays, please refer to the product selection guideline.

Product Selection Guideline

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