CM2851
150mA CMOS LDO W
ITH
EN & PG
GENERAL DESCRIPTION
The CM2851 family is positive, linear regulators featured low
quiescent current (30µA typ.) with low dropout voltage,
making them ideal for battery applications. The space-saving
SOT-23-5 package is attractive for “Pocket” and “Hard Held”
applications.
These rugged devices have both Thermal Shutdown, and
Current Fold-back to prevent device failure under the “Worst”
of operating conditions.
An additional feature is a “Power Good” detector, which pulls
low when the output is out of regulation.
The CM2851 is stable with an output capacitance of 2.2µF or
greater.
FEATURES
!
Very Low Dropout Voltage
Low Current Consumption: Typ. 30µA, Max. 35µA
High Accuracy Output Voltage: +/- 1.5%
Guaranteed 150mA Output
Input Range of 2.5V to 7.0V
Thermal Shutdown
Current Limiting
Power Good Output Function
Compact Package: SOT-23-5
Factory Pre-set Output Voltages
Short Circuit Current Fold-Back
Low Temperature Coefficient
!
!
!
!
!
!
!
!
!
!
!
APPLICATIONS
!
!
!
!
Battery-powered devices
Personal communication devices
Home electric/electronic appliances
PC peripherals
24 Hours Technical Support--WebSIM
Champion provides customers an online circuit simulation tool
called WebSIM. You could simply logon our website at
www.champion-micro.com for details.
TYPICAL APPLICATIONS
IN
1M
Ω
IN
PG
C M 2851
GND
OUT
EN
OUT
5V
C1
1uF
C
PG
* For program m ing
delay > typ. 5m s
(O ptional)
C2
4 .7 u F
2003/12/05
Rev. 1.1
Champion Microelectronic Corporation
Page 1
CM2851
150mA CMOS LDO W
ITH
EN & PG
PIN CONFIGURATION
SOT-23-5
Top View
5
4
OUT
GND
2
VIN
1
BLOCK DIAGRAM
IN
EN
3
PG
OUT
1uA
O vercurrent
Shutdown
Therm al
Shutdown
EN
R1
PG
-
+
AM P
-
+
Vref = 1.176V
Vref x 85%
R2
Digital PG
1-5m s
GND
2003/12/05
Rev. 1.1
Champion Microelectronic Corporation
Page 2
CM2851
150mA CMOS LDO W
ITH
EN & PG
ORDERING INFORMATION
Part Number
CM2851ACIM25
CM2851SIM25
Output Voltage
1.2V
3.3V
Temperature Range
-40℃ ~ +85℃
-40℃ ~ +85℃
Package
SOT-23-5
SOT-23-5
Note: For other pre-set output voltage, please contact Champion Sales office.
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Output Current
Output Voltage
…………….……………………………. +7V
…………………….……
P
D
/ (V
IN
- Vo)
…………………… GND-0.3V to V
IN
+0.3V
………………………………………… B
OPERATING RATINGS
Ambient Temperature Range (T
A
) ……... -40℃ to +85℃
Junction Temperature Range
…..…... -40℃ to +125℃
ESD Classification
THERMAL INFORMATION
Parameter
Thermal Resistance (Θ
jc
)
Internal Power Dissipation (P
D
)
(ΔT = 100℃)
Maximum Junction Temperature
Maximum Lead Temperature (10 Sec)
SOT-23-5
SOT-23-5
Maximum
160
250
150
300
Unit
℃/W
mW
℃
℃
*With Junction sink capable of twice times ofΘ
jc
Caution: Stress above the listed absolute rating may cause permanent damage to the device.
2003/12/05
Rev. 1.1
Champion Microelectronic Corporation
Page 3
CM2851
150mA CMOS LDO W
ITH
EN & PG
ELECTRICAL CHARACTERISTICS
T
A
= +25℃; unless otherwise noted
CM2851
Min.
Note 1
I
O
= 1mA
I
O
= 150mA,
V
OUT
=V
O(NOM)
-1.5%,
1.2V< V
O(NOM)
<=2.0V
2.0V< V
O(NOM)
<=2.5V
2.5V< V
O(NOM)
150
450
150
30
30
-0.1
-.015
-0.3
135
0.02
0.03
0.06
0.2
150
30
25
I
O
= 100mA
C
O
=2.2µF ceramic
f=10Hz to 100kHz
I
O
= 10mA
f=1kHz
f=10kHz
f=100kHz
C
O
=2.2µF
60
50
40
30
0.1
1.0
V
IN
/2+0.8V
0
0
V
IN
/2-0.8V
2.0
3.0
0.1
85
85
1
7
0.1
1
7
3.0
V
IN
μVrms
μA
μA
V
V
μA
V
%V
O(NOM)
μA
V
V
ms
dB
V
OUT
< 2.0V
2.0V<V
OUT
< 3.0V
3.0V<V
OUT
300
35
35
0.1
0.15
0.3
1
-1.5
Typ.
Max.
7
1.5
1300
800
300
mA
mA
mA
μA
μA
%
%
%
%
℃
℃
ppm/℃
mV
Parameter
Input Voltage
Output Voltage Accuracy
Dropout Voltage
Output Current
Current Limit
Short Circuit Current
Quiescent Current
Ground Pin Current
Line Regulation
Load Regulation
Over Temperature Shutdown
Over Temperature Hysteresis
V
OUT
Temperature Coefficient
Power Supply Rejection
Symbol
V
IN
V
OUT
V
DROPOUT
I
O
I
LIM
I
SC
I
Q
I
GND
REG
LINE
REG
LOAD
OTS
OTH
TC
PSRR
Test Conditions
Unit
V
%
V
OUT
> 1.2V
V
OUT
> 1.2V
V
OUT
< 0.8V
I
O
= 0mA
I
O
= 1mA to 150mA
I
OUT
=1mA, V
IN
=V
OUT
+1 to
V
OUT
+2
I
O
=1mA to 150mA
Output Voltage Noise
EN Input Bias Current
EN Input Threshold
Shutdown Supply Current
Shutdown Output Voltage
Output Under Voltage
PG Leakage Current
PG Voltage Rating
PG Voltage Low
Delay Time to PG
Note 1.
V
IN(MIN)
= V
OUT
+ V
DROPOUT
eN
I
EH
I
EL
V
EH
V
EL
I
SD
V
O, SD
V
UV
I
LC
V
PG
V
OL
t
DELAY
V
EN
=V
IN
, V
IN
=2.7V to 7V
V
EN
=0V, V
IN
=2.7V to 7V
V
IN
=2.7V to 7V
V
IN
=2.7V to 7V
V
IN
=5.0V, V
OUT
=0V, V
EN
< V
EL
I
O
=150mA
2.5V<=V
OUT
<= 5.0V
1.2V<=V
OUT
<= 2.5V
V
PG
= 7V
V
OUT
in regulation
I
SINK
= 2mA
V
IN
=2.5V to 6.0V
(Note 2)
Note 2: Delay time will be varied by input voltage, but the delay time will still be in the
spec from 1ms to 7ms when VIN rise time <2ms.
2003/12/05
Rev. 1.1
Champion Microelectronic Corporation
Page 4
CM2851
150mA CMOS LDO W
ITH
EN & PG
DETAILED DESCRIPTION
The CM2851 family of CMOS regulators contain a PMOS pass transistor, voltage reference, error amplifier, over-current
protection, output short circuit protection, thermal shutdown, and power good function.
The P-channel pass transistor receives data from the error amplifier, over-current shutdown, short output protection, and thermal
protection circuits. During normal operation, the error amplifier compares the output voltage to a precision reference. Over-current
and Thermal shutdown circuits become active when the junction temperature exceeds 150℃, or the current exceeds 150mA.
During thermal shutdown, the output voltage remains low. Normal operation is restored when the junction temperature drops
below 120℃.
The CM2851 switches from voltage mode to current mode when the load exceeds the rated output current. This prevents
over-stress. The CM2851 also incorporates current fold-back to reduce power dissipation when the output is short-circuited. This
feature becomes active when the output drops below 0.95V, and reduces the current flow by 65%. Full current is restored when
the voltage exceeds 0.95V.
EXTERNAL CAPACITOR
The CM2851 is stable with an output capacitor to ground of 2.2µF or greater. It can keep stable even with higher or poor ESR
capacitors. A second capacitor is recommended between the input and ground to stabilize VIN. The input capacitor should be
larger than 0.1µF to have a beneficial effect. All capacitors should be placed in close proximity to the pins. A “quiet” ground
termination is desirable.
ENABLE
The Enable pin normally floats high. When actively, pulled low, the PMOS pass transistor shut off, and all internal circuits are
powered down. In this state, the quiescent current is less than 1µA. This pin behaves much like an electronic switch.
POWER GOOD
The CM2851 includes the Power Good feature. Under normal operating condition which means output voltage is within the SPEC,
PG should be high. If Vout is less than 85% VOUT SPEC, PG will go low. As VOUT comes back and reaches to the 95%
VOUT SPEC, the PG will go high after 1ms~7ms again. (See Timing Diagram as below)
VIN = VEN= 3.3V, Iload = 120mA, VOUT = 1.2V, Delay time = 4.5ms
2003/12/05
Rev. 1.1
Champion Microelectronic Corporation
Page 5
嵌入式系统
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
