Short circuit protection a first on relay

The AQY210KS PhotoMOS Relay from Matsushita Electric Works has been designed with a short circuit protection function, which it claims is a market first.

The AQY210KS PhotoMOS Relay from Matsushita Electric Works has been designed with a short circuit protection function, which it claims is a market first.

This function will protect sensitive equipment (such as modems, telephone and measurement equipment) from the dangers of excessive current loads, which can cause the device permanent damage.

Short Circuit Protection Function switches relay off in 50 microseconds When the load current exceeds specifications, the AQY210KS goes into an open state and completely cuts off the input current within 50 microseconds.

This immediately protects the circuit from damage caused by over current and because there is almost no heating, the relay itself remains intact.

To make the circuit available again, the input current is simply reset.

The AQY210KS come in a miniature SO Package 4-PIN type design, which measures just 4.3 x 4.4 x 2.1mm (W x L x H).

Despite its small size, the AQY210KS can handle a continuous load current of 120mA at voltages up to 350VAC, with a channel resistance of typically 23 Ohms.

Like conventional PhotoMOS relays, the AQY210KS is excellent at switching low-level analogue signals and has an almost unlimited life expectancy.

A typical application for the AQY210KS relay would be in the area of modem circuit protection.

Due to international differences in telecom standards and formats it is often impossible to know if the telephone line you have just plugged into is analogue or digital.

A typical analogue line can deliver around 125mA whilst a digital line has the ability to deliver anywhere from 160mA up to a maximum of 2A.

In the event of a modem being exposed to these excessive current loads it would be permanently damaged, cutting off the user.

The AQY210KS instantly protects the modem from excessive input currents.

The user would then be presented with a non-connecting modem but the circuit would still be functional.

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