CM2855
300mA CMOS LDO W
ITH
EN & PG
GENERAL DESCRIPTION
The CM2855 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-23-6 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 CM2855 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: +/- 2.5%
Guaranteed 300mA Output
Input Range of 2.6V to 7.0V
Thermal Shutdown
Current Limiting
Power Good Output Function
Compact Package: SOT-23-6
Adjustable Output Voltages
Short Circuit Current Fold-Back
Low Temperature Coefficient
APPLICATIONS
Battery-powered devices
Personal communication devices
Home electric/electronic appliances
PC peripherals
TYPICAL APPLICATIONS
IN
IN
EN
PG
OUT
C M 2855
GND
ADJ
OUT
R1
5V
C1
1uF
R2
C3
2.2uF
Note:
1. Suggest to add a small Cap 100pF between OUT and connection of R1and R2 to get less VOUT ripple
Vout = Vref * (1 + R1/R2); Vref = 1.176V
2. Enable pin can not be floating.
2004/6/01
Rev. 1.2
Champion Microelectronic Corporation
Page 1
CM2855
300mA CMOS LDO W
ITH
EN & PG
PIN CONFIGURATION
SOT-23-6
Top View
6
5
4
VOUT
ADJ
GND
VIN
1
2
BLOCK DIAGRAM
IN
EN
PG
3
OUT
1uA
Overcurrent
Shutdown
Thermal
Shutdown
EN
PG
-
+
AMP
ADJ
-
+
Vref x 85%
Vref = 1.176V
GND
2004/6/01
Rev. 1.2
Champion Microelectronic Corporation
Page 2
CM2855
300mA CMOS LDO W
ITH
EN & PG
ORDERING INFORMATION
Part Number
CM2855IM26
CM2855GIM26*
*Note: G : Suffix for Pb Free Product
Output Voltage
Adjustable
Adjustable
Temperature Range
-40℃ ~ +85℃
-40℃ ~ +85℃
Package
SOT-23-6
SOT-23-6
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Output Current
Output Voltage
…………….……………………………. +7V
…………………….……
P
D
/ (V
IN
- Vo)
…………………… GND-0.3V to V
IN
+0.3V
OPERATING RATINGS
Ambient Temperature Range (T
A
) ……... -40℃ to +85℃
Junction Temperature Range
…..…... -40℃ to +125℃
ESD Classification ………………………………………… B
THERMAL INFORMATION
Parameter
Thermal Resistance (Θ
JA
)
Internal Power Dissipation (P
D
)
Maximum Junction Temperature
Maximum Lead Temperature (10 Sec)
SOT-23-6
SOT-23-6
Maximum
260
Note 1
150
300
Unit
℃/W
℃
℃
Caution: Stress above the listed absolute rating may cause permanent damage to the device.
Note 1:
P
D(MAX)
= (T
J(MAX)
– T
A
)/θ
JA
, where
θ
JA
depends on the printed circuit layout.
2004/6/01
Rev. 1.2
Champion Microelectronic Corporation
Page 3
CM2855
300mA CMOS LDO W
ITH
EN & PG
ELECTRICAL CHARACTERISTICS
T
A
= +25℃; V
IN
=
V
IN(MIN)
unless otherwise noted
CM2855
Min.
Note 2
I
O
= 1mA
I
O
= 300mA,
V
OUT
=V
O(NOM)
-2.5%,
1.2V< V
O(NOM)
<=2.0V
2.0V< V
O(NOM)
<=2.5V
2.5V< V
O(NOM)
300
800
150
30
30
1.168
-0.1
-.015
-0.3
1.176
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
0.1
1
7
89.5
96.5
0.1
7.8
3.8
3.0
V
IN
μVrms
μA
μA
V
V
μA
V
μA
V
%
%
V
ms
ms
dB
35
35
1.184
0.1
0.15
0.3
1
-2.5
Typ.
Max.
7
2.5
1300
800
300
mA
mA
mA
μA
μA
V
%
%
%
%
℃
℃
ppm/℃
mV
Parameter
Input Voltage
Output Voltage Accuracy
Dropout Voltage
Output Current
Current Limit
Short Circuit Current
Quiescent Current
Ground Pin Current
Bandgap Reference
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
V
BG
REG
LINE
REG
LOAD
OTS
OTH
TC
PSRR
Test Conditions
Unit
V
%
V
OUT
> 1.2V
V
OUT
> 1.2V
V
OUT
< 0.8V
(Note 3)
I
O
= 0mA
I
O
= 1mA to 300mA
V
O
= V
BG
, load = 10mA
I
OUT
=1mA, V
IN
=V
OUT
+1 to
V
OUT
+2
V
OUT
< 2.0V
2.0V<V
OUT
< 3.0V
3.0V<V
OUT
I
O
=1mA to 300mA
Output Voltage Noise
EN Input Bias Current
EN Input Threshold
Shutdown Supply Current
Shutdown Output Voltage
PG Leakage Current
PG Voltage Rating
PG Low Threshold
PG High Threshold
PG Voltage Low
Delay Time to PG
(Note 3)
eN
I
EH
I
EL
V
EH
V
EL
I
SD
V
O, SD
I
LC
V
PG
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
=300mA
V
PG
= 7V
V
OUT
in regulation
% of V
O
(PG ON)
% of V
O
(PG OFF)
V
OL
t
DELAY
I
SINK
= 2mA
V
IN
= 5V
V
IN
= 3V
Note 2.
V
IN(MIN)
= V
OUT
+ V
DROPOUT
Note 3.
Guaranteed by Design, not 100% test. VIN start time needs to be less than 2ms.
Note 4.
Short Circuit Current and Current limit value will increase as input voltage is larger than V
IN(MIN)
2004/6/01
Rev. 1.2
Champion Microelectronic Corporation
Page 4
CM2855
300mA CMOS LDO W
ITH
EN & PG
DETAILED DESCRIPTION
The CM2855 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 300mA.
During thermal shutdown, the output voltage remains low. Normal operation is restored when the junction temperature drops
below 120℃.
The CM2855 switches from voltage mode to current mode when the load exceeds the rated output current. This prevents
over-stress. The CM2855 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 CM2855 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
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 CM2855 includes the Power Good feature. Normally, Pin 4 is floating, however, when the output is lower than 85% of the
specified voltage, it pulls low. This can occur under the following conditions:
1)
2)
3)
Input Voltage too low
During Over-Temperature
During Over-Current
2004/6/01
Rev. 1.2
Champion Microelectronic Corporation
Page 5
微控制器 MCU
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