CM2576
3A S
TEP
D
OWN
V
OLTAGE
R
EGULATOR
GENERAL DESCRIPTION
The CM2576 series are step-down switching regulators with
all required active functions. It is capable of driving 3A load
with excellent line and load regulations. These devices are
available in fixed output voltages of 3.3V, 5V, and an
adjustable output version.
The CM2576 series offers a high-efficiency replacement for
popular three-terminal linear regulators. Also it requires a
minimum number of external components. It substantially not
only reduces the area of board size but also the size of the
heat sink, and in some cases no heat sink is required.
±4% tolerance on output voltage within specified input
voltages and output load conditions is guaranteed. Also, the
oscillator frequency accuracy is within ±10%. External
shutdown is included, featuring 70µA (typical) standby current.
The output switch includes cycle-by-cycle current limiting, as
well as thermal shutdown for full protection under fault
conditions.
FEATURES
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Guaranteed 3A output current
3.3V, 5V, and adjustable versions
Wide input voltage range, up to 40V
Internal oscillator of 52KHz fixed frequency
Wide adjustable version output voltage range, from
1.23V to 37V±4% max over line and load conditions
Low standby current, typ. 70µA, at shutdown mode
Requires only 4 external components
Thermal shutdown and current limit protection
P+ product enhancement tested
APPLICATIONS
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LCD Monitors
ADD-ON Cards Switching Regulators
High Efficiency Step-Down Regulators
Efficient Pre-regulator for Linear Regulators
ORDERING INFORMATION
Package Type
TO-220
CM2576SCN220
CM2576ZJCN220
CM2576CN220
TO-263
CM2576SCN263
CM2576ZJCN263
CM2576CN263
Temperature Range
-40℃ ~ +125℃
-40℃ ~ +125℃
-40℃ ~ +125℃
Output Voltage
3.3V
5.0V
ADJ.
2003/08/07
Preliminary
Rev. 1.1
Champion Microelectronic Corporation
Page 1
CM2576
3A S
TEP
D
OWN
V
OLTAGE
R
EGULATOR
PIN CONFIGURATION
TO-220
Top View
TO-263
Top View
E N A B LE
5
4
3
2
1
FB
GND
V
OUT
V
IN
V
OUT
GND
FB
4
1 2
3
5
ABSOLUTE MAXIMUM RATINGS
Input Voltage (V
POWER
) …….………………………………………….……. +45V
ENABLE
Pin Input Voltage ….…………………………………. –0.3V
≦V≦V
IN
Operating Junction Temperature Range, T
J
……………...… 0℃ to +150℃
Storage Temperature ………………………………….….…... -65℃ to +150℃
Lead Temperature (10 sec.) ……..……………………..….…………….... 260℃
POWER DISSIPATION TABLE
Package
TO-220
TO-263
Θ
JA
(℃/W)
℃
45
45
Derating factor (mW/℃)
℃
T
A
>= 25℃
℃
22.2
22.2
T
A
<= 25℃
℃
Power rating (mW)
2775
2775
T
A
= 70℃
T
A
= 85℃
℃
℃
Power rating (mW) Power rating (mW)
1776
1443
1776
1443
Note:
1.
Θ
JA
: Thermal Resistance-Junction to Ambient, D
F
: Derating factor, P
O
: Power consumption.
2.
Junction Temperature Calculation: T
J
= T
A
+ (P
D
x
Θ
JA
), P
O
= D
F
x (T
J
– T
A
)
The
Θ
JA
numbers are guidelines for the thermal performance of the device/PC-board system.
All of the above assume no ambient airflow.
Θ
JT
: Thermal Resistance-Junction to Ambient, T
C
: case (Tab) temperature, T
J
= T
C
+ (P
D
x
Θ
JA
)
RESOMMENDED OPERATING CONDITIONS
Parameter
Input Voltage (V
IN
)
Temperature Range
Symbol
V
IN
T
J
Min.
-40
Typ.
Max
40
125
Units
V
℃
2003/08/07
Preliminary
Rev. 1.1
EN ABLE
V
IN
Champion Microelectronic Corporation
Page 2
CM2576
3A S
TEP
D
OWN
V
OLTAGE
R
EGULATOR
Note 1:
External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system
performance. Refer to Application Information for details.
Note 2:
The oscillator frequency reduces to approximately 11KHz in the event of fault conditions, such as output short or
overload. And the regulated output voltage will drop approximately 40% from the nominal output voltage. This self-protection
feature lowers the average power dissipation by lowering the minimum duty cycle from 5% down to approximately 2%.
Note 3:
For these parameters, FB is removed from V
OUT
and connected to +12V to force the output transistor OFF.
Note 4:
V
OUT
pin sourcing current. No diode, inductor or capacitor connect to V
OUT
.
Note 5:
FB is removed from V
OUT
and connected to 0V.
BLOCK DIAGRAM
2003/08/07
Preliminary
Rev. 1.1
Champion Microelectronic Corporation
Page 4
测试/测量
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