Relay Basics
General Knowledge of Relays
- Part 1 What is a Relay?
- Part 2 Types of Omron Relays
MOS FET Relays
Definition
MOS FET relays are semiconductor relays that use MOS FET for their outputs.
Non-contact relays, mainly used for switching and connecting signals, are used in a wide range of applications, including semiconductor test equipment, measuring instruments, and security equipment.

Features
Ultra-small and lightweight | SSOP, USOP and other new ultra-small packaging VSON are emerging, which contributes to miniaturization of the entire device. |
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Low drive current | The drive current is about 2 to 15mA under the recommended operating condition (normal). We also have a minimum of 0.2 mA products which contribute to energy saving of whole device. |
Longer-life | Our MOS FET relays have a non-contact structure using an optical signal transmission method. We have achieved long durability without deterioration of life due to contact friction. |
small leakage current | Because of its high resistance to external surges and no added snubber circuit, the leakage current is extremely small, typically 1 nA or less in the off state. (G3VM-□GR□,-□LR□,-□PR□,-□UR□) |
superior impact resistance | Since the internal parts are completely molded and there are no mechanical parts such as movable parts, they are excellent in shock resistance and vibration resistance. |
Quiet sound | Since there is no switching noise caused by metal contacts unlike machine relays, it contributes to noise reduction of device. |
High insulation | Since there is no switching noise caused by metal contacts unlike machine relays, they contribute to noise reduction of device. |
Precise control of small analog signals | Since the dead band is extremely small compared to a triac etc, the input waveform of a small analog signal is converted into an output waveform with little distortion. |
For more detailed information
Types
Product map by MOS FET relay type

Structure
Basic structures and operating of MOS FET relays

MOS FET relays consist of following three chips:
- LED chips
- PDA (photodiode array) chip
- MOS FET chips

MOS FET relays operate according to the following principles.
- The LED lights when the current flows to the input side.
- The light from the LED is received by the photodiode array, which generates electricity to convert the light back to a voltage
- This voltage passes through the control circuit to become the gate voltage to drive the MOS FET.
Application example
- FA/Industrial equipment
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Machine tools, custom power supplies, FA devices (programmable controller/temperature controller/timer)
ApplicationStatus output, various signals, small solenoid valve, power supply external output of small motor -
- Machine tools
- Timer
- Test measurement/testers
-
Semiconductor test equipment (ATE)/semiconductor test interface boards, oscilloscopes, data loggers, I/O boards
ApplicationMeasurement signal switching, power supply- ATE
(Semiconductor test equipment) - Tester
- Security devices
-
Smoke and gas detectors, home security panels, human body detection sensors and TV doorphones
Applicationstatus output, various signal output, small solenoid valve, power supply external output of small light- Smoke and gas detector
- Home security panel
- Amusement equipment
-
paper money discrimination units, game ball and medal lending machines (interposed machine), IT equipment
Applicationstatus output, various signals- Gaming machines
- Part 1 What is a Relay?
- Part 2 Types of Omron Relays