MIC5246
Micrel
MIC5246
150mA
µ
Cap CMOS LDO Regulator
Final Information
General Description
The MIC5246 is an efficient, precise CMOS voltage regulator
optimized for low-noise applications. The MIC5246 offers
better than 1% initial accuracy, extremely-low-dropout volt-
age (typically 150mV at 150mA) and constant ground current
(typically 85µA)over load . The MIC5246 features an error
flag that indicates an output fault condition such as overcurrent,
thermal shutdown and dropout. The MIC5246 provides a very
low noise output, ideal for RF applications where quiet
voltage sources are required.
Designed specifically for hand-held and battery-powered
devices, the MIC5246 provides a TTL-logic-compatible en-
able pin. When disabled, power consumption drops nearly to
zero.
The MIC5246 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 MIC5246 also offers a range of fixed output
voltages.
Features
•
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•
•
•
•
•
•
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•
Error flag indicates fault condition
Ultralow dropout—100mV @ 100mA
Load independent, ultralow ground current: 85µA
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
Cellular phones and pagers
Cellular accessories
Battery-powered equipment
Laptop, notebook, and palmtop computers
PCMCIA V
CC
and V
PP
regulation/switching
Consumer/personal electronics
SMPS post-regulator/dc-to-dc modules
High-efficiency linear power supplies
Applications
Ordering Information
Part Number
MIC5246-2.6BM5
MIC5246-2.7BM5
MIC5246-2.8BM5
MIC5246-2.85BM5
MIC5246-3.0BM5
MIC5246-3.3BM5
Marking
LT26
LT27
LT28
LT2J
LT30
LT33
Voltage
2.6V
2.7V
2.8V
2.85V
3.0V
3.3V
Junction Temp. Range
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
Package
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
Other voltages available. Contact Micrel for details.
Typical Application
47kΩ
V
IN
MIC5246-x.xBM5
1
2
Enable
Shutdown
3
4
5
V
OUT
C
OUT
FLG
C
FLG
EN
EN (pin 3) may be
connected directly
to IN (pin 1).
Low-Noise Regulator Application
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
June 2000
1
MIC5246
MIC5246
Micrel
Pin Configuration
EN GND IN
3
2
1
LTxx
4
5
FLG
OUT
MIC5246-x.xBM5
Pin Description
Pin Number
1
2
3
4
5
Pin Name
IN
GND
EN
FLG
OUT
Pin Function
Supply Input
Ground
Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;
logic low = shutdown. Do not leave open.
Error Flag (Output): Open-drain output. Active low indicates an output
undervoltage condition.
Regulator Output
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
FLG
) .................................. 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
FLG
) .................................. 0V to V
IN
Junction Temperature (T
J
) ....................... –40°C to +125°C
Thermal Resistance
(θ
JA
)...................................... 235°C/W
MIC5246
2
June 2000
MIC5246
Micrel
Electrical Characteristics
V
IN
= V
OUT
+ 1V, 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
V
IN
– V
OUT
Parameter
Output Voltage Accuracy
Line Regulation
Load Regulation
Dropout Voltage,
Note 5
Conditions
I
OUT
= 0mA
V
IN
= V
OUT
+ 0.1V to 6V
I
OUT
= 0.1mA to 150mA,
Note 4
I
OUT
= 100µA
I
OUT
= 50mA
I
OUT
= 100mA
I
OUT
= 150mA
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
= 2.7V to 5.5V, regulator shutdown
V
IN
= 2.7V to 5.5V, regulator enabled
V
IL
≤
0.4V
V
IH
≥
1.6V
Shutdown Resistance Discharge
Thermal Protection
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
Error Flag
V
FLG
V
OL
I
FL
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
Min
–1
–2
–0.3
Typical
Max
1
2
Units
%
%
%/V
%
mV
mV
mV
mV
mV
µA
µA
µA
dB
mA
0
2
1.5
50
100
150
0.2
85
85
50
0.3
3
5
85
150
200
250
1
150
150
Quiescent Current
Ground Pin Current,
Note 6
V
EN
≤
0.4V (shutdown)
I
OUT
= 0mA
I
OUT
= 150mA
f = 120Hz, C
OUT
= 10µF
V
OUT
= 0V
160
Power Supply Rejection
Current Limit
300
0.8
1.6
1
0.01
0.01
500
0.4
V
V
µA
µA
Ω
°C
°C
150
10
Low Threshold
High Threshold
Output Logic-Low Voltage
Flag Leakage Current
% of V
OUT
(Flag ON)
% of V
OUT
(Flag OFF)
I
L
= 100µA, fault condition
flag off, V
FLG
= 6V
90
96
0.02
0.01
0.4
%
%
V
µA
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.
Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V
differential. For outputs below 2.7V, dropout voltage is the input-to-output voltage differential with the minimum input voltage 2.7V. Minimum
input operating voltage is 2.7V.
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 error flag 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.
Note 6.
Note 7.
June 2000
3
MIC5246
51单片机
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