MP1543
1.5A, 500KHz Synchronous
Rectified Step-up Converter
MP1543 Rev. 1.0 www.MonolithicPower.com 1
1/11/2006 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
The Future of Analog IC Technology
TM
TM
DESCRIPTION
The MP1543 is a highly efficient, synchronous,
fixed frequency, current-mode step-up converter
with output to input disconnect, inrush current
limiting and internal soft-start. It includes an error
amplifier, ramp generator, comparator, N-Channel
switch and P-Channel synchronous rectified
switch (which greatly improves efficiency). The
output disconnect feature allows the output to be
completely isolated from the input in shutdown
mode.
The 500KHz switching frequency allows for
smaller external components producing a
compact solution for a wide range of load
currents. The internal compensation and soft-start
minimizes the external component count and
limits the inrush current during startup. The
MP1543 regulates the output voltage up to 6V
and provides up to 400mA from a 2-cell AA with
a 3.3V output.
The MP1543 is offered in a thin SOT23-5
package.
EVALUATION BOARD REFERENCE
Board Number Dimensions
EV1543DJ-01A 2.4”X x 2.4”Y x 0.4”Z
FEATURES
• Over 90% Efficiency
• Output to Input Disconnect at Shutdown Mode
• Internal Synchronous Rectifier
• Inrush Current Limiting and Internal Soft-Start
• Internal Compensation
• 1.5A Typical Switch Current Limit
• 500KHz Fixed Switching Frequency
• Zero Current Shutdown Mode
• Thermal Shutdown
• 5-Pin TSOT-23 Package
APPLICATIONS
• MP3 Players
• Handheld Computers and PDAs
• Digital Still and Video Cameras
• External Modems
• Small LCD Displays
“MPS” and “The Future of Analog IC Technology” are Trademarks of Monolithic
Power Systems, Inc.
TYPICAL APPLICATION
MP1543
SW
OUT
FB
GND
EN
4
3
1
2
5
V
IN
1.8V - 3.2V
EN
V
OUT
3.3V
400mA
V
OUT
=3.3V
V
IN
=1.8V
V
IN
=2.4V
V
IN
=3V
100
90
80
70
60
50
40
30
EFFICIENCY (%)
1 10 100 1000
LOAD CURRENT (mA)
MP1543-EC01
Efficiency vs
Load Current
