This document introduces LT3689, an industrial/automotive step-down regulator that can accept 3.6V to 36V and includes power-on reset and watchdog timer functions.
The LT3689 is a constant frequency, current mode step-down regulator designed for microprocessor-based applications in automotive and industrial environments. It accepts input voltages from 3.6V to 36V and includes protection against transients up to 60V. The device delivers 800mA of continuous output current with high efficiency at light loads, achieved through selectable Burst Mode or Pulse-Skipping modes.
| Continuous Output Current | 800mA |
|---|---|
| Input Voltage Range | 3.6V to 36V |
| Transient Protection | up to 60V |
| Switching Frequency Range | 350kHz to 2.2MHz |
| Quiescent Current (Shutdown) | less than 0.5µA |
The LT3689 supports Low Ripple Burst Mode operation and Pulse-Skipping mode, selectable via the SYNC pin.
The reset timeout period is adjustable by connecting an external capacitor between the CPOR pin and ground.
The DA pin monitors the current in the catch diode to protect against inductor current runaway situations.