RT9818A-30GV

RT9818A-30GV is a cost competitive high accuracy reset IC with supervisor functions. It contains an independent 200mV reference, a 60sec watchdog timer, a voltage monitor, and a dedicated power-on reset circuit. It has two output pins, RESET and WDO. The devices supports a wide range of supply voltage from 1V to 5.5V to incorporate a diverse range of system voltage requirements.

Application Field

RT9818A-30GV offers a smart solution to supervise power-up reset, reset of digital logic IC, reset of battery-backed memories, and system reset generation. The independent voltage comparator monitors input voltage to detect system brown-out. The 200mV reference can be used in many other applications, such as overage voltage detection, motor control, and power supply reset generation. It also provides independent(or in combination with a capacitive element) power-on reset.

Working Principle

When power is applied, the RESET output is pulled low after an internal fixed power-on-reset period (about 40 ms). With power is at VDD1 level, the WDO output is pulled low after a fixed time-out period, about 60 to 75 seconds. The time-out period is adjustable by external capacitor, and the accuracy is better than 3%.

The RESET output is also reset when a voltage below the reset voltage is applied to the VDD1. The reset output will remain activated until power is above the reset voltage. The WDO pin remains high until the on-chip watchdog timer times out, while simultaneously feeding back an internal RC oscillator. The watchdog timer is active whenever power is applied.

RT9818A-30GV also incorporates a wide range of external logic controls to allow even more flexibility in reset/watchdog grooming. It features reset enable/disable, reset status flag, and reset delay control options. All of which allow the user to customize their system reset requirements.