LM2742 Datasheet, PDF (1/22 Pages) National Semiconductor (TI) – N-Channel FET Synchronous Buck Regulator Controller for Low Output Voltages

PRELIMINARY
March 2004
LM2742
N-Channel FET Synchronous Buck Regulator Controller
for Low Output Voltages
General Description
The LM2742 is a high-speed, synchronous, switching regu-
lator controller. It is intended to control currents of 0.7A to
20A with up to 95% conversion efficiencies. Power up and
down sequencing is achieved with the power-good flag,
adjustable soft-start and output enable features. The
LM2742 operates from a low-current 5V bias and can con-
vert from a 1V to 16V power rail. The part utilizes a fixed-
frequency, voltage-mode, PWM control architecture and the
switching frequency is adjustable from 50kHz to 2MHz by
setting the value of an external resistor. Current limit is
achieved by monitoring the voltage drop across the on-
resistance of the low-side MOSFET, which enables on-times
on the order of 40ns, one of the best in the industry. The wide
range of operating frequencies gives the power supply de-
signer the flexibility to fine-tune component size, cost, noise
and efficiency. The adaptive, non-overlapping MOSFET
gate-drivers and high-side bootstrap structure helps to fur-
ther maximize efficiency. The high-side power FET drain
voltage can be from 1V to 16V and the output voltage is
adjustable down to 0.6V.
Features
n Input power from 1V to 16V
n Output voltage adjustable down to 0.6V
n Power Good flag, adjustable soft-start and output enable
for easy power sequencing
n Reference Accuracy: 1.5% (0˚C - 125˚C)
n Current limit without sense resistor
n Soft start
n Switching frequency from 50 kHz to 2 MHz
n 40ns typical minimum on-time
n TSSOP-14 package
Applications
n POL power supply modules
n Cable Modems
n Set-Top Boxes/ Home Gateways
n DDR Core Power
n High-Efficiency Distributed Power
n Local Regulation of Core Power
Typical Application
© 2004 National Semiconductor Corporation DS200875
20087510
www.national.com