The MAX7389/MAX7390 are replacements for ceramic resonators, crystals, and supervisory functions for microcontrollers in 3.3V and 5V applications. They provide clock source, reset, and watchdog functions. The devices are resistant to EMI and vibration, and operate reliably at high temperatures.
The MAX7389 and MAX7390 replace ceramic resonators and crystals, providing a clock source, reset, and watchdog functions for 3.3 V and 5 V microcontroller applications. The devices offer factory‑trimmed frequencies from 1 MHz to 16 MHz, a +10 mA clock‑output drive, and operate over a temperature range of –40 °C to +125 °C.
Pin‑strapping of WDS1 and WDS2 selects one of nine watchdog timeout periods (16 ms to 2048 ms). The MAX7390 includes a SPEED pin that halves the clock frequency for low‑power operation. Detailed electrical characteristics, absolute maximum ratings, and package dimensions are provided for design integration.
| Operating Supply Voltage | 2.7 V to 5.5 V |
|---|---|
| Clock Output Frequency (factory preset) | 1 MHz to 16 MHz |
| Clock Output Drive Current | +10 mA |
| Operating Supply Current (12 MHz version) | 5.5 mA |
| Operating Temperature Range | -40 °C to +125 °C |
| Watchdog Timeout Range | 16 ms to 2048 ms |
The devices operate from 2.7 V up to 5.5 V.
The SPEED pin, when driven low, halves the factory‑trimmed clock frequency.
The clock output can source up to +10 mA.