LTC3775 - High Frequency Synchronous Step-Down Voltage Mode DC/DC Controller

Features

• Wide V_IN Range: 4.5V to 38V
• Line Feedforward Compensation
• Low Minimum On-Time: t_ON(MIN) < 30ns
• Powerful Onboard MOSFET Drivers
• Leading Edge Modulation Voltage Mode Control
• ±0.75%, 0.6V Reference Voltage Accuracy Over Temperature
• V_OUT Range: 0.6V to 0.8V_IN
• Programmable, Cycle-by-Cycle Peak Current Limit
• Sense Resistor or R_DS(ON) Current Sensing
• Programmable Soft-Start
• Synchronizable Fixed Frequency from 250kHz to 1MHz
• Selectable Pulse-Skipping or Forced Continuous
• Modes of Operation
• Low Shutdown Current: 14μA Typical
• Thermally Enhanced 3mm × 3mm QFN Package

Typical Application

Description

The LTC3775 is a high efficiency synchronous step-down switching DC/DC controller that drives an all N-channel power MOSFET stage from a 4.5V to 38V input supply voltage. A patented line feedforward compensation circuit and a high bandwidth error amplifier provide very fast line and load transient response.

High step-down ratios are made possible by a low 30ns minimum on-time, allowing extremely low duty cycles MOSFET R_DS(ON) current sensing maximizes efficiency. Alternatively, a sense resistor can be used for higher current limit accuracy. Continuous monitoring of the voltages across the top and bottom MOSFETs allows cycle-by-cycle control of the inductor current, configurable by external resistors.

The soft-start function controls the duty cycle during start-up, providing a smooth output voltage ramp up. The operating frequency is user programmable from 250kHz to 1MHz and can be synchronized to an external clock.

Packaging

Order Info

• Part numbers ending in PBF are lead free. Please contact LTC marketing for information on lead based finish parts.
• Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
• Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number	Package	Pins	Temp	Price (1-99)	Price (1k)*	RoHS Data
LTC3775EUD#PBF	QFN	16	E	$2.56	$1.79	View
LTC3775EUD#TRPBF	QFN	16	E		$1.85	View
LTC3775IUD#PBF	QFN	16	I	$2.99	$2.09	View
LTC3775IUD#TRPBF	QFN	16	I		$2.15	View
Buy Now
Request Samples

^* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Applications

• Automotive Systems
• Telecom and Industrial Power Supplies
• Point of Load Applications

Simulate

To simulate selected Linear Technology products, please download LTSpice / SwitcherCAD III. This powerful schematic capture and simulation tool includes macro models for 80% of Linear Technology's switching regulators, over 200 op amp models, as well as resistors, transistors and MOSFET models.

For other simulation tools, visit our Design Simulation and Device Models page.