1

Rev. 08/19/05

SP6128A Low Voltage, Synchronous Step Down PWM Controller

© Copyright 2005 Sipex Corporation

SP6128A

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

■ High Efficiency: Greater Than 95% Possible

■ Discontinuous Startup for Precharged Output

■ Accurate Fixed 300kHz Frequency Operation

■ Fast Transient Response

■ Internal Soft Start Circuit

■ Accurate 0.8V Reference Allows Low Output

Voltages

■ Resistor Programmable Output Voltage

■ Resistor Programmable Overcurrent Threshold

Sensing

■ Hiccup Mode Current Limit Protection

■ Dual N-Channel MOSFET Synchronous Driver

■ Quiescent Current: 500µA, 30µA in Shutdown

■ 14 pin TSSOP

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 SP6128A 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 SP6128A pack-

aged in an 14-pin TSSOP, is especially suited for low voltage applications where cost, small

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

allowing small inductor values and minimizing PC board space. The SP6128A drives two

N-channel power MOSFETs for improved efficiency and includes an accurate 0.8V reference

for low output voltage applications.

®

1

2

3

4

5

6

7

GL

PGND

GND

COMP

NC

14

13

12

11

10

9

8

BST

GH

SWN

NC

NC

SP6128A

14 pin TSSOP

BST

SWN

COMP

GH

GL

GND

C1

2.2µF

SP6128A

Q1

FDS6690A

C4

1µF

D2

STPS2L25U

PGND

NC

NC

NC

R1

5

1

2

3

4

5

6

7

14

13

12

11

10

9

8

C3

68pF

R2

7.87k

C2 4.7n

R3

8k

D1

MBR0530

L1

1.0µH

Q2

FDS6690A

C12

4.7nF

R4

1.7k

R5

800

C8

10µF

C9

10µF

C10

10µF

C11

470µF

2.5V/10A

C5

10µF

C6

10µF

C7

10µF

3V to 5.5V

TYPICAL APPLICATION CIRCUIT

Now Available in Lead Free Packaging

DESCRIPTION