1

Date: 5/25/04

SP6123 Low Voltage, Synchronous Step Down PWM Controller

© Copyright 2004 Sipex Corporation

SP6123/SP6123A

■ Optimized for Single Supply, 3V - 5.5V Applications

■ High Efficiency: Greater Than 95% Possible

■ Accurate Fixed 300kHz (SP6123) or 500kHz

(SP6123A) Frequency Operation

■ Fast Transient Response

■ Internal Soft Start Circuit

■ Accurate 0.8V Reference Allows Low Output

Voltages

■ Resistor Programmable Output Voltage

Sensing

■ Hiccup Mode Current Limit Protection

■ Dual N-Channel MOSFET Synchronous Driver

■ Quiescent Current: 500µA, 30µA in Shutdown

■ 8-Pin Surface Mount Package

Low Voltage, Synchronous Step-Down PWM Controller

Ideal for 2A to 10A, Small Footprint, DC-DC Power Converters

APPLICATIONS

■ DSP

■ Microprocessor Core

■ I/O & Logic

■ Industrial Control

■ Distributed Power

■ Low Voltage Power

The SP6123 is a fixed frequency, voltage mode, synchronous PWM controller designed to

work from a single 5V or 3.3V input supply, providing excellent AC and DC regulation for high

efficiency power conversion. Requiring only few external components, the SP6123 pack-

aged in an 8-pin NSOIC, is especially suited for low voltage applications where cost, small

size and high efficiency are critical. The operating frequency is internally set to 300kHz

(SP6123) or 500kHz (SP6123A), allowing small inductor values and minimizing PC board

space. The SP6123 drives an all N-channel synchronous power MOSFET stage for improved

efficiency and includes an accurate 0.8V reference for low output voltage applications.

®

TYPICAL APPLICATION CIRCUIT

BST

SWN

COMP

GH

GL

GND

CC

4.7nF

RZ

15k

CB

2.2µF

SP6123A

CP

56pF

FDS6890A

680µF

R1

10k

IN

0.8V to 5.0V

2A to 10A

(1.6V, 4A shown)

CBST

1µF

MBR0530

L1

1.5µH

FDS6890A

470µF

1µF

R2

10k

470µF

STPS2L25U

3V to 5.5V

1

2

3

4

5

6

7

8

COMP

GL

BST

GH

SWN

SP6123

8 Pin NSOIC

GND

Now Available in Lead Free Packaging

DESCRIPTION