The MAX7378 is a dual-speed silicon oscillator that replaces ceramic resonators, crystals, crystal-oscillator modules, and discrete reset circuits. It provides the primary and secondary clock source and reset function for microcontrollers in 3V, 3.3V, and 5V applications. The MAX7378 features a factory-programmed high-speed oscillator, a 32.768kHz oscillator, a clock selector input, and a microprocessor (µP) power-on-reset (POR) supervisor. The clock output can be switched at any time between the high-speed clock and the 32.768kHz clock for low-power operation. Switchover is synchronized internally to provide glitch-free clock switching. Unlike typical crystal and ceramic resonator oscillator circuits, the MAX7378 is resistant to vibration and EMI. The high-output-drive current and absence of high-impedance nodes make the oscillator less susceptible to dirty or humid operating conditions. With a wide operating temperature range as standard, the MAX7378 is a good choice for demanding home appliance, industrial, and automotive environments. The MAX7378 is available in an 8-pin µMAX package. Refer to the MAX7384 data sheet for frequencies ≥10MHz. The MAX7378 standard operating temperature range is -40°C to +125°C. See the Applications Information section for the extended operating temperature range.
The MAX7378 is a dual‑speed silicon oscillator with a high‑speed 600 kHz‑10 MHz clock and a fixed 32.768 kHz low‑speed clock. It provides a programmable reset output and can switch between clocks without glitches, making it suitable for microcontroller clocking in 3 V‑5 V systems.
The device is offered in an 8‑pin UMAX package, operates from –40 °C to +125 °C, and features up to +10 mA clock‑output drive, low jitter, and various reset‑output configurations (push‑pull active‑low, push‑pull active‑high, open‑drain). Detailed electrical characteristics, pin descriptions, and ordering information are provided in the datasheet.
| Operating Supply Voltage | 2.7 V to 5.5 V |
|---|---|
| High‑Speed Frequency Range | 600 kHz to 10 MHz |
| Low‑Speed Frequency | 32.768 kHz |
| Clock Output Drive Capability | +10 mA |
| Operating Temperature Range | -40 °C to +125 °C |
| Reset Output Hold Time | 100 µs (typical) |
The device operates from 2.7 V up to 5.5 V.
The SPEED pin selects the clock speed: low selects the 32.768 kHz low‑speed clock, high selects the high‑speed clock.
The MAX7378 offers push‑pull active‑low, push‑pull active‑high, and open‑drain active‑low reset output options.