MIC5246
Micrel
June 2000
1
MIC5246
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 85
A)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 IttyBittyTM SOT-23-5
package, the MIC5246 also offers a range of fixed output
voltages.
Typical Application
1
5
2
3
4
C
OUT
Enable
Shutdown
EN
V
OUT
MIC5246-x.xBM5
EN (pin 3) may be
connected directly
to IN (pin 1).
V
IN
47k
FLG
C
FLG
Low-Noise Regulator Application
MIC5246
150mA
Cap CMOS LDO Regulator
Preliminary Information
Features
Error flag indicates fault condition
Ultralow dropout--100mV @ 100mA
Load independent, ultralow ground current: 85
A
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
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
Ordering Information
Part Number
Marking
Voltage
Junction Temp. Range
Package
MIC5246-2.6BM5
LT26
2.6V
40
C to +125
C
SOT-23-5
MIC5246-2.7BM5
LT27
2.7V
40
C to +125
C
SOT-23-5
MIC5246-2.8BM5
LT28
2.8V
40
C to +125
C
SOT-23-5
MIC5246-2.85BM5
LT2J
2.85V
40
C to +125
C
SOT-23-5
MIC5246-3.0BM5
LT30
3.0V
40
C to +125
C
SOT-23-5
MIC5246-3.3BM5
LT33
3.3V
40
C to +125
C
SOT-23-5
Other voltages available. Contact Micrel for details.
Micrel, Inc. 1849 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 944-0970 http://www.micrel.com
IttyBitty is a trademark of Micrel, Inc.
MIC5246
Micrel
MIC5246
2
June 2000
Pin Configuration
IN
OUT
FLG
EN
LTxx
1
3
4
5
2
GND
MIC5246-x.xBM5
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
(
JA
) ...................................... 235
C/W
Pin Description
Pin Number
Pin Name
Pin Function
1
IN
Supply Input
2
GND
Ground
3
EN
Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;
logic low = shutdown. Do not leave open.
4
FLG
Error Flag (Output): Open-drain output. Active low indicates an output
undervoltage condition.
5
OUT
Regulator Output
MIC5246
Micrel
June 2000
3
MIC5246
Electrical Characteristics
V
IN
= V
OUT
+ 1V, V
EN
= V
IN;
I
OUT
= 100
A; T
J
= 25
C, bold values indicate 40
C
T
J
+125
C; unless noted.
Symbol
Parameter
Conditions
Min
Typical
Max
Units
V
O
Output Voltage Accuracy
I
OUT
= 0mA
1
1
%
2
2
%
V
LNR
Line Regulation
V
IN
= V
OUT
+ 0.1V to 6V
0.3
0
0.3
%/V
V
LDR
Load Regulation
I
OUT
= 0.1mA to 150mA, Note 4
2
3
%
V
IN
V
OUT
Dropout Voltage, Note 5
I
OUT
= 100
A
1.5
5
mV
I
OUT
= 50mA
50
85
mV
I
OUT
= 100mA
100
150
mV
I
OUT
= 150mA
150
200
mV
250
mV
I
Q
Quiescent Current
V
EN
0.4V (shutdown)
0.2
1
A
I
GND
Ground Pin Current, Note 6
I
OUT
= 0mA
85
150
A
I
OUT
= 150mA
85
150
A
PSRR
Power Supply Rejection
f = 120Hz, C
OUT
= 10
F
50
dB
I
LIM
Current Limit
V
OUT
= 0V
160
300
mA
Enable Input
V
IL
Enable Input Logic-Low Voltage
V
IN
= 2.7V to 5.5V, regulator shutdown
0.8
0.4
V
V
IH
Enable Input Logic-High Voltage
V
IN
= 2.7V to 5.5V, regulator enabled
1.6
1
V
I
EN
Enable Input Current
V
IL
0.4V
0.01
A
V
IH
1.6V
0.01
A
Shutdown Resistance Discharge
500
Thermal Protection
Thermal Shutdown Temperature
150
C
Thermal Shutdown Hysteresis
10
C
Error Flag
V
FLG
Low Threshold
% of V
OUT
(Flag ON)
90
%
High Threshold
% of V
OUT
(Flag OFF)
96
%
V
OL
Output Logic-Low Voltage
I
L
= 100
A, fault condition
0.02
0.4
V
I
FL
Flag Leakage Current
flag off, V
FLG
= 6V
0.01
A
Note 1.
Exceeding the absolute maximum rating may damage the device.
Note 2.
The device is not guaranteed to function outside its operating rating.
Note 3.
Devices are ESD sensitive. Handling precautions recommended.
Note 4.
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.
Note 5.
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.
Note 6.
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.
Note 7.
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.
MIC5246
Micrel
MIC5246
4
June 2000
0
10
20
30
40
50
60
1x10
1
1x10
2
1x10
3
1x10
4
1x10
5
1x10
6
PSRR (dB)
FREQUENCY (Hz)
Power Supply Rejection Ratio
I
LOAD
= 100
A
0
10
20
30
40
50
60
1x10
1
1x10
2
1x10
3
1x10
4
1x10
5
1x10
6
PSRR (dB)
FREQUENCY (Hz)
Power Supply Rejection Ratio
I
LOAD
= 50mA
0
10
20
30
40
50
60
1x10
1
1x10
2
1x10
3
1x10
4
1x10
5
1x10
6
PSRR (dB)
FREQUENCY (Hz)
Power Supply Rejection Ratio
I
LOAD
= 100mA
0
10
20
30
40
50
60
1x10
1
1x10
2
1x10
3
1x10
4
1x10
5
1x10
6
PSRR (dB)
FREQUENCY (Hz)
Power Supply Rejection Ratio
I
LOAD
= 150mA
80
82
84
86
88
90
0
1
10
100
1000
GROUND CURRENT (
A)
OUTPUT CURRENT (mA)
Ground Current
vs. Output Current
0
20
40
60
80
100
-40
-10
20
50
80
110 140
GROUND CURRENT (
A)
TEMPERATURE (
C)
Ground Pin Current
Iload = 100
A
0
20
40
60
80
100
-40
-10
20
50
80
110 140
GROUND CURRENT (
A)
TEMPERATURE (
C)
Ground Pin Current
I
LOAD
= 150mA
0
20
40
60
80
100
0
1
2
3
4
5
GROUND CURRENT (
A)
VOLTAGE IN (V)
Ground Pin Current
I
LOAD
= 100
A
0
20
40
60
80
100
0
1
2
3
4
5
GROUND CURRENT (
A)
VOLTAGE IN (V)
Ground Pin Current
I
LOAD
= 150mA
0
1
2
3
4
0
1
2
3
4
5
VOLTAGE OUT (V)
VOLTAGE IN (V)
Dropout Characteristics
150mA
100
A
0
50
100
150
200
-40
-10
20
50
80
110 140
DROPOUT VOLTAGE (
V)
TEMPERATURE (
C)
Dropout Voltage
I
LOAD
= 100
A
0
50
100
150
200
250
-40
-10
20
50
80
110 140
DROPOUT VOLTAGE (
V)
TEMPERATURE (
C)
Dropout Voltage
I
LOAD
= 150mA
Typical Characteristics
MIC5246
Micrel
June 2000
5
MIC5246
Typical Characteristics
0
100
200
300
400
-40
-10
20
50
80
110 140
SHORT CIRCUIT CURRENT (mA)
TEMPERATURE (
C)
Short Circuit Current
vs. Temperature
V
OUT
= 0V
3.20
3.24
3.28
3.32
3.36
3.40
-40
-10
20
50
80
110 140
OUTPUT VOLTAGE (V)
TEMPERATURE (
C)
Output Voltage
vs. Temperature
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