From the basics to applications of Automation Controls
Filled with valuable information helpful for engineers!

click here for the "SELECTION GUIDE" list page



Introduction to Relays – What are PhotoMOS?

What are PhotoMOS?

A PhotoMOS is a semiconductor relay with an LED as an input and MOSFET as an output.
It is used in various fields to improve device reliability and reduce size.


Application of PhotoMOS

Basic Structure

<Optical Isolation>

Optical Isolation


Sectional drawing 1

Sectional drawing 2


<Capacitor Coupled Isolation>

Capacitor Coupled Isolation


Epoxy                          -----    Epoxy resin

LED                             -----    Light Emitting Diode

MOSFET                     -----     Acronym for Metal-Oxide-Semiconductor Field Effect Transistor
                                               A transistor that has structure efficiently combining Metal (Electrical                                                         conductor), Oxide film (Insulator), and Semiconductor (substance that                                                     has intermediate quality)

Photoelectric element  -----    Solar battery and control circuit


How PhotoMOS Operate

<Optical Isolation>

<Optical Isolation> When operated

 <Optical Isolation> When turned off


<Capacitor Coupled Isolation>

<Capacitor Coupled Isolation> When operated

<Capacitor Coupled Isolation> When turned off


Advantages of PhotoMOS

Obviously the PhotoMOS differ from the conventional electro-mechanical relays.
PhotoMOS are classified to semiconductor relays that have no moving contact, therefore they are superior to conventional electro-mechanical relays in life-expectance and reliability of contacts, operation speed, and their sizes.

But they also distinguish themselves from other switching solutions that utilize photo-couplers, photo-transistors etc.. PhotoMOS have MOSFET for output, therefore they are the most suitable devices for small analog signal switching.

 Advantages of PhotoMOS



Panasonic offers PhotoMOS for various purposes with a wide range of products.
The PhotoMOS is provided in eight types according to features and recommended purposes.

 Lineup of PhotoMOS

 Lineup of PhotoMOS


Package Variations

Our PhotoMOS are offered in various packages from VSSOP, the smallest-footprint in our lineup to SIL, which can control up to 10A. We offer SOP16pin with 4a output and the built-in input resistor type. Panasonic has its own package options featuring their contribution to space-saving design and reducing man-hours.

PhotoMOS Package Variations

 PhotoMOS Package Variations

We offer a line-up of voltage drive products with a built-in input resistor such as SSOP, SOP4pin, and SOP16pin. We can also meet your requirements in other packages after consultation. Please contact us.


▼Product list by package

▼Go to Product Information for PhotoMOS