The LT3693 is an adjustable frequency (200kHz to 2.4MHz) monolithic buck switching regulator that accepts input voltages up to 36V. A high efficiency 95m switch is included on the die along with a boost Schottky diode and the necessary oscillator, control, and logic circuitry. Current mode topology is used for fast transient response and good loop stability. Shutdown reduces input supply current to less than 1μA while a resistor and capacitor on the RUN/SS pin provide a controlled output voltage ramp (soft-start). A power good flag signals when VOUT reaches 91% of the programmed output voltage. The LT3693 is available in 10-Pin MSOP and 3mm × 3mm DFN packages with exposed pads for low thermal resistance.
The LT3693 is a constant‑frequency, current‑mode step‑down switching regulator with a wide input range of 3.6 V to 36 V and an adjustable switching frequency from 200 kHz to 2.4 MHz. It delivers up to 3.5 A of output current and supports an output voltage range of 0.79 V to 30 V with soft‑start capability.
The document includes detailed electrical characteristics, pin configurations, typical performance curves, and package descriptions for both MSOP and DFN options. It also explains the operation of key pins such as BOOST, RUN/SS, SYNC, and PG, and provides application guidance for automotive battery regulation, portable power, and industrial supplies.
| Input Voltage Range | 3.6 V to 36 V |
|---|---|
| Output Voltage Range | 0.79 V to 30 V (soft‑start) |
| Maximum Output Current | 3.5 A |
| Adjustable Switching Frequency | 200 kHz to 2.4 MHz |
| Quiescent Current (Shutdown) | < 1 pA |
| Feedback Reference Voltage | 0.790 V |
The LT3693 operates with an input voltage from 3.6 V up to 36 V.
The device can supply up to 3.5 A of continuous output current.
Tie the RUN/SS pin to ground to place the LT3693 in shutdown mode, reducing input current to less than 0.5 pA; tie it to 2.5 V or higher for normal operation.
The switching frequency can be set between 200 kHz and 2.4 MHz.