Microcontroller Clock Generator with Watchdog

The MAX7389/MAX7390 provide a clock source, reset, and watchdog functions. The watchdog timer is pin programmable and provides watchdog timeout values in the 16ms to 2048ms range. The MAX7389 provides a separate watchdog output that is used as a status indicator or to control safety-critical system elements.

The MAX7390 features a clock-speed select that reduces the output frequency by half. This functionality allows the microcontroller to operate at reduced power and may be used to extend the time available to perform housekeeping tasks, such as writing data to flash during a power failure.

The MAX7389/MAX7390 clock outputs are factory programmed to a frequency in the 1MHz to 16MHz range. Four standard frequencies are available. Other frequencies are available upon request. The maximum operating supply current is 5.5mA with a clock frequency of 12MHz.

Unlike typical crystal and ceramic resonator oscillator circuits, the MAX7389/MAX7390 are resistant to EMI, vibration, and operate reliably at high temperatures. The high-output drive current and absence of high-impedance nodes make the oscillator invulnerable to dirty or humid operating conditions.

The MAX7389/MAX7390 are available in an 8-pin µMAX® package. The MAX7389/MAX7390 standard operating temperature range is from -40°C to +125°C.