Linear Technology Corporation has introduced a low minimum on-time wide input voltage range synchronous step-down DC/DC switching regulator controller that drives all N-channel power MOSFET stages.

With less than a 30 ns minimum on-time, the LTC3775 is suitable for high step-down ratios. The 4.5 V to 38 V input range encompasses a wide variety of applications, including most intermediate bus voltages and battery chemistries. The onboard MOSFET gate drivers allow the use of high power external MOSFETs to produce output currents up to 20 A with output voltages that range from 0.6 V to 80 percent of the input voltage, making the LTC3775 ideal for automotive, industrial, medical, datacom and telecom applications.

A constant-frequency, leading edge modulation, voltage mode line feed forward architecture provides a selectable fixed or phase-lockable (PLL) frequency from 250 kHz to 1 MHz. Output current sensing is accomplished by monitoring the current in both the top-side and bottom-side MOSFET, allowing cycle-by-cycle control of the inductor current. In addition, the LTC3775 has adjustable soft-start to control the turn-on time and manage inrush current. Selectable pulse skip mode or forced continuous mode is user controlled to optimize light load efficiency. The LTC3775 features a precision 0.6 V reference with an accuracy of ±0.75 percent over a -40 to 125 degrees C operating temperature range.

Summary of Features: LTC3775

• VIN Range: 4.5 V to 38 V

• VOUT Range: 0.6 V to 0.8 VIN

• Low Minimum On-Time <30 ns

• Strong Onboard N-Channel MOSFET Driver

• Leading Edge Modulation Voltage Mode Control

• Line Feedforward Compensation

• Sense Resistor or RDS(ON) Current Sensing

• Programmable Cycle by Cycle Current Limit

• Phase-Lockable Fixed Frequency from

• 250 kHz to 1 Mhz

• Programmable Soft-Start

• ±0.75 percent Reference Voltage Accuracy over

• -40 to +125 degrees C

Availability and Pricing

The LTC3775 is available in a thermally enhanced 3 mm x 3 mm QFN-16 package. The LTC3775E operates from -40 to 85 degrees C with the 1000-piece price starting at $1.79 each. The LTC3775I industrial grade version operates from -40 to 85 degrees C, with a 1,000-piece price that starts at $2.09 each. Both versions are available from stock.

Datasheet:

LTC3775