2.2V Input High Power Step-Down DC/DC Controller Uses Standard 5V N-Channel MOSFETs

News Release  www.linear.com
2.2V Input High Power Step-Down DC/DC Controller Uses
Standard 5V N-Channel MOSFETs
MILPITAS, CA – December 6, 2006 – Linear Technology Corporation introduces the LT3740, a
high output power step-down synchronous controller that operates from very low input voltages
without needing an auxiliary 5V gate drive supply. In addition to a DC/DC step-down controller,
the LT3740 integrates a DC/DC step-up converter for generating its own MOSFET gate drive
voltage. This function permits the use of inexpensive off-the-shelf 5V gate-drive N-channel
MOSFETs, offering up to 3% higher efficiency than sub-logic gate-drive MOSFETs and
eliminating the need for a secondary supply. The LT3740 is ideal for converting input supplies
ranging from 2.2V to 22V to an output as low as 0.8V and at load currents from 2A to 20A with
93% typical efficiency. Applications include distributed power systems, point-of-load regulation
and conversion of logic supplies. In particular, the LT3740 can step down from 5V, 3.3V and
2.5V rails.
The LT3740 operates at a fixed frequency of 300kHz and employs valley current mode
control to deliver excellent transient response and very low on-times. In addition, the LT3740
uses low-side MOSFET current-sense architecture for current limiting and overload protection,
eliminating the need for a sense resistor while improving efficiency. Three current limit
threshold levels can be selected by connecting the range pin to ground, open or the input voltage.
Furthermore, a power good signal is available to monitor the output voltage and the device has a
tracking function that allows output voltage control during power up and power down.
The LT3740 is offered in a 16-lead 5mm x 3mm DFN package with an operating
temperature range from -40°C to 85°C. Pricing starts at $1.95 each in 1,000-piece quantities.
2.2V Input High Power Step-Down DC/DC Controller Uses
Standard 5V N-Channel MOSFETs
Page 2
Photo Caption: 2.2V Input High Power Step-Down DC/DC Controller
Summary of Features: LT3740
Low Input Voltage: 2.2V
High Output Power – up to 20A
5V Drive for N-Channel MOSFETs Eliminates Auxiliary 5V Supply
Uses Standard 5V Logic-Level N-Channel MOSFETs
Valley Current Mode Control for Excellent Line and Load Regulation
No Sense Resistor Required (uses MOSFET RDS(ON) for Sensing)
Three Selectable Current Limit Levels
Power Good Signal and Tracking Function
About Linear Technology
Linear Technology Corporation, a manufacturer of high performance linear integrated circuits,
was founded in 1981, became a public company in 1986 and joined the S&P 500 index of major
public companies in 2000. Linear Technology products include high performance amplifiers,
comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery
chargers, data converters, communications interface circuits, RF signal conditioning circuits, and
many other analog functions. Applications for Linear Technology’s high performance circuits
include telecommunications, cellular telephones, networking products such as optical switches,
notebook and desktop computers, computer peripherals, video/multimedia, industrial
instrumentation, security monitoring devices, high-end consumer products such as digital
cameras and MP3 players, complex medical devices, automotive electronics, factory automation,
process control, and military and space systems. For more information, visit www.linear.com
LT, LTC, LTM, Burst Mode and
are registered trademarks of Linear Technology Corp.
Press Contacts:
John Hamburger, Director Marketing Communications
[email protected]
Tel 408-432-1900 ext
Doug Dickinson, Media Relations Manager
[email protected]