CM3706A
1.5MHz, 600mA Synchronous Step-Down Regulator
GENERAL DESCRIPTION
The CM3706A is a high efficiency monolithic synchronous
buck regulator using a constant frequency, current mode
architecture. The device is available in an adjustable
version. Supply current with no load is 300uA and drops to
<1uA in shutdown. The 2.5V to 6.5V input voltage range
makes the CM3706A ideally suited for single Li-Ion, two to
four AA battery-powered applications. 100% duty cycle
provides low dropout operation, extending battery life in
portable systems. PWM pulse skipping mode operation
provides very low output ripple voltage for noise sensitive
applications. Switching frequency is internally set at
1.5MHz, allowing the use of small surface mount inductors
and capacitors. The internal synchronous switch increases
efficiency and eliminates the need for an external Schottky
diode. Low output voltages are easily supported with the
0.6V feedback reference voltage.
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FEATURES
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High Efficiency: Up to 96%
1.5Mhz Constant Switching Frequency
600mA Output Current at V
IN
=3V
Integrated Main switch and synchronous rectifier. No
Schottky Diode Required
2.5V to 6.5V Input Voltage Range
Output Voltage as Low as 0.6V
100% Duty Cycle in Dropout
Low Quiescent Current: 300µA
Slope Compensated Current Mode Control for Excellent Line
and Load Transient Response
Short Circuit Protection
Thermal Fault Protection
<1uA Shutdown Current
Space Saving 5-Pin Thin TSOT23 package
APPLICATIONS
Cellular and Smart Phones
Microprocessors and DSP Core Supplies
Wireless and DSL Modems
PDAs
MP3 / MP4 Player
Portable Instruments
Digital Still and Video Cameras
TYPICAL APPLICATIONS
IN
2.5V TO
5.5V
Cin
4.7uF
4
3
2.2uH
V
IN
1
SW
634k
OUT
CM3706A
RUN GND V
FB
2
316K
5
Cout
10uF
22PF
Figure 1. Basic Application Circuit with CM3706A adjustable version
2008/03/07
Rev. 1.0
Champion Microelectronic Corporation
Page 1
CHAMP [ CHAMPION MICROELECTRONIC CORP. ]
