MIC5268
Micrel
MIC5268
150mA
µ
Cap CMOS LDO Regulator w/Power Good
Preliminary Information
General Description
The MIC5268 is an efficient, precise CMOS voltage regulator
with power good output. The MIC5268 offers better than 3%
initial accuracy, and constant ground current (typically
100µA)over load .
The MIC5268 also works with low-ESR ceramic capacitors,
reducing the amount of board space necessary for power
applications, critical in hand-held wireless devices.
Key features include current limit, thermal shutdown, a push-
pull output for faster transient response, and an active clamp
to speed up device turnoff. Available in the IttyBitty™ SOT-23-5
package, the MIC5268 is a fixed 1.2V regulator.
Features
•
•
•
•
•
•
•
•
•
•
Power Good indicator
Load independent, ultralow ground current: 100µA
150mA output current
Current limiting
Thermal shutdown
Tight load and line regulation
“Zero” off-mode current
Stability with low-ESR capacitors
Fast transient response
TTL-Logic-controlled enable input
Applications
• Processor power-up sequencing
• Laptop, notebook, and palmtop computers
• PCMCIA V
CC
and V
PP
regulation/switching
Ordering Information
Part Number
MIC5268-1.2BM5
Marking
L512
Voltage
1.2
Junction Temp. Range*
–40°C to +125°C
Package
SOT-23-5
Other voltages available. Contact Micrel for details.
Typical Application
47k
V
IN
MIC5268-x.xBM5
1
2
Enable
Shutdown
3
4
5
V
OUT
C
OUT
PG
EN
EN (pin 3) may be
connected directly
to IN (pin 1).
1.2V Regulator with Power Good
IttyBitty is a trademark of Micrel, Inc.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
September 2002
1
MIC5268
MIC5268
Micrel
Pin Configuration
EN GND IN
3
2
1
L512
4
5
PG
OUT
MIC5268-x.xBM5
Pin Description
Pin Number
1
2
3
4
5
Pin Name
IN
GND
EN
PG
OUT
Pin Function
Supply Input
Ground
Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;
logic low = shutdown. Do not leave open.
Power Good Output
Regulator Output
MIC5268
2
September 2002
MIC5268
Micrel
Absolute Maximum Ratings
(Note 1)
Supply Input Voltage (V
IN
) .................................. 0V to +7V
Enable Input Voltage (V
EN
) .................................. 0V to V
IN
Flag Output Voltage (V
PG
) ................................... 0V to V
IN
Junction Temperature (T
J
) ...................................... +150°C
Storage Temperature ............................... –65°C to +150°C
Lead Temperature (soldering, 5 sec.) ....................... 260°C
ESD,
Note 3
Operating Ratings
(Note 2)
Input Voltage (V
IN
) ......................................... +2.7V to +6V
Enable Input Voltage (V
EN
) .................................. 0V to V
IN
Flag Output Voltage (V
PG
) ................................... 0V to V
IN
Junction Temperature (T
J
) ....................... –40°C to +125°C
Thermal Resistance
SOT-23(θ
JA
) ......................................................235°C/W
Electrical Characteristics
V
IN
= 2.7V, V
EN
= V
IN;
I
OUT
= 100µA; T
J
= 25°C,
bold
values indicate –40°C
≤
T
J
≤
+125°C; unless noted.
Symbol
V
O
∆V
LNR
∆V
LDR
I
Q
I
GND
PSRR
I
LIM
Enable Input
V
IL
V
IH
I
EN
Enable Input Logic-Low Voltage
Enable Input Logic-High Voltage
Enable Input Current
V
IN
= 5.5V, regulator shutdown
V
IN
= 5.5V, regulator enabled
V
IL
≤
0.4V; V
IN
= 5.5V
V
IH
≥
1.6V; V
IN
= 5.5V
Thermal Protection
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
Power Good , Note 6
V
PG
V
OL
I
PG
V
PG
Delay
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
Note 6.
Parameter
Output Voltage Accuracy
Line Regulation
Load Regulation
Quiescent Current
Ground Pin Current,
Note 5
Conditions
I
OUT
= 100µA
V
IN
= 2.7V to 6V
I
OUT
= 0.1mA to 150mA,
Note 4
V
EN
≤
0.4V (shutdown) PG = NC
I
OUT
= 0mA; V
IN
= 6.0V
I
OUT
= 150mA; V
IN
= 6.0V
f = 120Hz, C
OUT
= 4.7µF, I
OUT
= 150mA
V
OUT
= 0V
Min
–3
–4
–0.3
Typical
Max
3
4
0.3
Units
%
%
%/V
%
µA
µA
µA
dB
mA
3
0.45
110
110
tbd
160
350
5
1
150
150
Power Supply Rejection
Current Limit
0.4
1.6
0.01
0.01
V
V
µA
µA
°C
°C
150
10
Low Threshold
High Threshold
PG Output Logic-Low Voltage
Power Good Leakage Current
Delay time to Power Good
% of V
OUT
(PG ON)
% of V
OUT
(PG OFF)
I
L
= 10mA
power good off, V
PG
= 5.5V
See Timing Diagram
88
97
250
0.01
1
5
500
%
%
mV
µA
ms
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
Devices are ESD sensitive. Handling precautions recommended.
Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load
range from 0.1mA to 150mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground
pin current.
The power good is a function of the output voltage being 5% low and the detection of one of the following: overcurrent, overtemperature or
dropout. See “Applications Information” section for additional information.
September 2002
3
MIC5268
MIC5268
Micrel
Block Diagrams
IN
EN
Reference
Voltage
Startup/
Shutdown
Control
Quickstart
PULL
UP
Thermal
Sensor
FAULT
Error
Amplifier
Current
Amplifier
PULL
DOWN
OUT
Under-
voltage
Lockout
ACTIVE SHUTDOWN
Out of
Regulation
Detection
PG
Overcurrent
Dropout
Detection
Delay
GND
Timing Diagram
V
OUT
97%
88%
97%
Fault Condition
V
EN
Min - Max
1-5ms
1-5ms
V
PG
MIC5268
4
September 2002
MIC5268
Micrel
Typical Characteristics
Ground Current vs.
Input Voltage
113
GROUND CURRENT (µA)
GROUND CURRENT (µA)
Ground Current vs.
Output Current
99.4
99.2
99
98.8
98.6
98.4
98.2
0
20 40 60 80 100 120 140 160
OUTPUT CURRENT (mA)
GROUND CURRENT (µA)
Ground Current vs.
Temperature
110
111
109
107
105
103
101
99
97
I
OUT
= 100µA
V
IN
= 3.3V
105
100
95
90
I
OUT
= 100µA
I
OUT
= 150mA
I
OUT
= 150mA
95
2.5 3 3.5 4 4.5 5 5.5 6 6.5
INPUT VOLTAGE (V)
85
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
Short Circuit Current
vs. Input Voltage
SHORT CIRCUIT CURRENT (mA)
SHORT CIRCUIT CURRENT (mA)
Short Circuit Current
vs. Temperature
400
380
360
340
320
300
280
260
240
220
200
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
POWER GOOD DELAY (ms)
V
IN
= 3.3V
2
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
Power Good Delay
vs. Input Voltage
I
OUT
= 100µA
360
350
340
330
320
310
300
290
280
270
260
2.6 3.1 3.6 4.1 4.6 5.1 5.6 6.1
INPUT VOLTAGE (V)
1.1
1
2.6 3.1 3.6 4.1 4.6 5.1 5.6 6.1
INPUT VOLTAGE (V)
Power Good Delay
vs. Temperature
POWER GOOD DELAY (ms)
2
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
1.195
V
IN
= 3.3V
OUTPUT VOLTAGE (V)
1.19
1.185
1.18
1.175
Output Voltage
vs. Input Voltage
1.195
OUTPUT VOLTAGE (V)
I
OUT
= 100µA
1.19
1.185
1.18
1.175
1.17
1.165
1.16
0
Output Voltage vs.
Output Current
I
OUT
= 150mA
1.17
2.6 3.1 3.6 4.1 4.6 5.1 5.6 6.1
INPUT VOLTAGE (V)
V
IN
= 3.3V
20 40 60 80 100 120 140 160
OUTPUT CURRENT (mA)
Output Voltage vs.
Temperature
1.205
ENABLE VOLTAGE (V)
OUTPUT VOLTAGE (V)
1.2
1.195
1.19
1.185
I
OUT
= 100µA
1.18
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
Enable Voltage vs.
Input Voltage
1.4
ENABLE VOLTAGE (V)
1.3
1.2
1.1
1
0.9
0.8
0.7
I
OUT
= 100µA
1.2
1.15
1.1
1.05
1
0.95
0.9
0.85
Enable Voltage vs.
Temperature
V
IN
= 3.3V
0.6
2.6 3.1 3.6 4.1 4.6 5.1 5.6 6.1
INPUT VOLTAGE (V)
0.8
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
September 2002
5
MIC5268
嵌入式系统
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