Seiko Instruments Releases New Convenience Timer IC for Automotive Applications
The S-35720 Series is suitable for time management after engine shut-down, enabling improved regulation of automotive emissions and EV battery safety.


Seiko Instruments Inc. (SII) announced the release of the new S-35720 Series convenience timer IC suitable for managing relative time after engine shut-down with its optional alarm time in 1 second increments from 1 second to 194 days.

The S-35720 Series is designed to help meet exacting automotive emissions regulations such as EURO 6 and enhance EV battery safety.

These regulations call for the status management of different facets of the Fi-ECU (fuel injection system) after engine shut-down. For example, controlling the catalyst activation status based on elapsed time and temperature, and periodically managing fuel vaporization volume (with the use of pressure detection to check for fuel leaks).

These functions typically require an operating microcontroller. However, by utilizing the S-35720 Series convenience timer, which has ultra-low current consumption of only 200nA, the need to maintain power to the microcontroller during non-measurement periods is eliminated, drastically decreasing standby ECU (engine control unit) power consumption.

The S-35720 Series is also suitable for detecting the down periods of electric vehicles, i.e. the period of time the vehicle is not in use.

In addition, it can help monitor the battery management systems (BMS) of electric vehicle batteries when they are not charged by notifying the owner that the vehicle has not been used for a half year and detecting time parameters such as the number of days during which the vehicle has not been used.

The S-35720 series can output an alarm interrupt signal in a specified time after a microcontroller stops. It compares the timer values with the values set to the SET0 and SET1 pins, and then outputs an interrupt signal when the values match. The timer is a 24-bit binary-up counter. Four types of interrupt time are available depending on the SET0 and SET1 pins settings. Customers can select a time-out type from one-shot loop time-out, handshake time-out, and toggle operation.

It is designed to withstand the demanding automotive environment, where temperatures run as high as 125 ˚C. The package is small 8-pin TMSOP.


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