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.
◆
◆
◆
◆
◆
◆
◆
◆
◆
FEATURES
◆
◆
◆
◆
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
CM3706A
1.5MHz, 600mA Synchronous Step-Down Regulator
PIN CONFIGURATION
TSOT23-5
Top View
BLOCK DIAGRAM
2008/03/07
Rev. 1.0
Champion Microelectronic Corporation
Page 2
CM3706A
1.5MHz, 600mA Synchronous Step-Down Regulator
PIN DESCRIPTION
Pin No.
1
Symbol
RUN
Description
Regulator Enable control input. Drive RUN above 1.5V to turn on the part. Drive RUN
below 0.3V to turn it off.
2
3
4
5
GND
SW
VIN
FB
Ground Pin.
Power Switch Output. It is the Switch note connection to Inductor. This pin connects to the
drains of the internal P-CH and N-CH MOSFET switches.
Supply Input Pin. Must be closely decoupled to GND, Pin 2, with a 2.2µF or greater ceramic
capacitor.
VFB (CM3706A): Feedback Input Pin. Connect FB to the center point of the external resistor
divider. The feedback threshold voltage is 0.6V.
In shutdown, all functions are disabled drawing <1µA supply
current. Do not leave RUN floating.
ORDERING INFORMATION/ MARKING
Adjustable Output Version
Part Number
CM3706AGIM25
Output
Adj
Top Mark
A1XY
Temp Range
-40°C to +85°C
2008/03/07
Rev. 1.0
Champion Microelectronic Corporation
Page 3
CM3706A
1.5MHz, 600mA Synchronous Step-Down Regulator
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Absolute maximum ratings are those values beyond which the
device could be permanently damaged.
Input Supply Voltage...................................................–0.3V to 7.0V Peak SW Sink and Source Current………...…………….. 1.5A
RUN, VFB Voltages ………………………...…– 0.3V to (VIN + 0.3V) Junction Temperature (Note 2) ........... ........................ 125°C
SW Voltage....…………........………..……..… – 0.3V to (VIN + 0.3V) Storage Temperature Range ....................... – 65°C to 150°C
Operating Temperature Range
….…………..…-40°C to +85°C
Lead Temperature (Soldering, 10 sec)......................... 300°C
OPERATING CONDITIONS
Temperature Range .......................... -40°C to 85°C
Vin Operating Range .........................2.5V to 5.5V
Thermal Resistance
(Note 3)
:
Package
TSOT23-5
Ө
JA
250°C/W
Ө
JC
110°C/W
Note 1:
Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.
Note 2:
T
J
is calculated from the ambient temperature T
A
and power dissipation P
D
according to the following formula:
CM3706A : T
J
= T
A
+ (P
D
)
╳
(
Ө
JA
)
Note 3:
Thermal Resistance is specified with approximately 1 square of 1 oz copper.
2008/03/07
Rev. 1.0
Champion Microelectronic Corporation
Page 4
CM3706A
1.5MHz, 600mA Synchronous Step-Down Regulator
(Unless otherwise stated, these specifications apply T
A
=25°C;
VIN=+3.6V)
maximum ratings are stress ratings only and functional device operation is not implied.
ELECTRICAL CHARACTERISTICS
Parameter
Input Voltage Range
Input DC Supply Current
Active Mode
Shutdown Mode
V
FB
=0.5V
Conditions
MIN
2.5
TYP
MAX
6.5
unit
V
300
0.1
0.5880
0.5865
0.5820
0.6000
0.6000
0.6000
400
1.0
0.6120
0.6135
0.6180
±30
µA
µA
V
V
V
nA
%/V
%/V
%/mA
V
FB
=0V, V
IN
=4.2V
T
A
= +25°C
Regulated Feedback Voltage
T
A
= 0°C
≤
T
A
≤
85°C
T
A
= -40°C
≤
T
A
≤
85°C
V
FB
Input Bias Current
Reference Voltage Line
Regulation
Output Voltage Line Regulation
Output Voltage Load Regulation
V
FB
= 0.65V
V
IN
= 2.5V to 5.5V,
0.01
0.04
0.0015
0.4
0.40
VIN = 2.5V to 5.5V,IOUT=10mA
IOUT from 10 to 600mA
Peak Inductor Current
Oscillator Frequency
R
DS(ON)
of P-CH MOSFET
R
DS(ON)
of N-CH MOSFET
SW Leakage
RUN Threshold
RUN Leakage Current
Thermal Shutdown Trip
Threshold
Output over voltage lockout
V
IN
=3V, V
FB
=0.5V or V
OUT
=90%
Duty Cycle <35%
V
FB
=0.6V or V
OUT
=100%
I
SW
= 300mA
I
SW
= -300mA
VRUN = 0V, VSW= 0V or 5V, VIN = 5V
-40°C
≤
T
A
≤
85°C
0.75
1.2
1.00
1.5
0.4
0.35
±0.01
1.25
1.8
0.50
0.45
±1
1.5
±1
A
MHz
Ω
Ω
µA
V
µA
℃
mV
0.3
0.45
±0.1
150
ΔVOVL
= VOVL – VFB
60
Note 4:
100% production test at +25°C. Specifications over the temperature range are guaranteed by design and
characterization.
2008/03/07
Rev. 1.0
Champion Microelectronic Corporation
Page 5
模拟与混合信号
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
