MIC5245
Micrel
June 2000
1
MIC5245
General Description
The MIC5245 is an efficient, precise CMOS voltage regulator
optimized for ultra-low-noise applications. The MIC5245 of-
fers better than 1% initial accuracy, extremely low dropout
voltage (typically 150mV at 150mA) and constant ground
current over load (typically 100
A). The MIC5245 provides a
very low noise output, ideal for RF applications where quiet
voltage sources are required. A noise bypass pin is also
available for further reduction of output noise.
Designed specifically for hand-held and battery-powered
devices, the MIC5245 provides a TTL logic compatible en-
able pin. When disabled, power consumption drops nearly to
zero.
The MIC5245 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
and power MSO-8 packages, the MIC5245 also offers a
range of fixed output voltages.
Typical Application
1
5
2
3
4
C
OUT
C
BYP
Enable
Shutdown
EN
V
OUT
(optional)
MIC5245-x.xBM5
EN (pin 3) may be
connected directly
o IN (pin 1).
V
IN
MIC5245
150mA
Cap CMOS LDO Regulator
Preliminary Information
Features
Ultralow dropout--100mV @ 100mA
Ultralow noise--30
V(rms)
Stability with tantalum or ceramic capacitors
Load independent, ultralow ground current
150mA output current
Current limiting
Thermal Shutdown
Tight load and line regulation
"Zero" off-mode current
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
MIC5245-2.5BM5
LS25
2.5V
40
C to +125
C
SOT-23-5
MIC5245-2.7BM5
LS27
2.7V
40
C to +125
C
SOT-23-5
MIC5245-2.8BM5
LS28
2.8V
40
C to +125
C
SOT-23-5
MIC5245-2.85BM5
LS2J
2.85V
40
C to +125
C
SOT-23-5
MIC5245-3.0BM5
LS30
3.0V
40
C to +125
C
SOT-23-5
MIC5245-3.1BM5
LS31
3.1V
40
C to +125
C
SOT-23-5
MIC5245-3.3BM5
LS33
3.3V
40
C to +125
C
SOT-23-5
MIC5245-3.3BMM
--
3.3V
40
C to +125
C
MSOP-8
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
1
2
3
4
8
7
6
5
MIC5245-3.3MM
ENABLE
SHUTDOWN
C
BYP
(OPTIONAL)
V
IN
V
OUT
C
OUT
Ultra-Low-Noise Regulator Application
MIC5245
Micrel
MIC5245
2
June 2000
Pin Configuration
IN
OUT
BYP
EN
LSxx
1
3
4
5
2
GND
MIC5245-x.xBM5
Absolute Maximum Ratings
(Note 1)
Supply Input Voltage (V
IN
) .................................. 0V to +7V
Enable Input Voltage (V
EN
) ................................. 0V to +7V
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
Junction Temperature (T
J
) ....................... 40
C to +125
C
Thermal Resistance
SOT-23
(
JA
) ..................................................... 235
C/W
MSOP-8
(
JA
) ...................................................... 80
C/W
Pin Description
Pin Number
Pin Number
Pin Name
Pin Function
Power MOS-8
SOT-23
2
1
IN
Supply Input
58
2
GND
Ground
1
3
EN
Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;
logic low = shutdown. Do not leave open.
4
4
BYP
Reference Bypass: Connect external 0.01
F capacitor to GND to reduce
output noise. May be left open.
3
5
OUT
Regulator Output
1
IN
OUT
BYP
8
GND
GND
GND
GND
7
6
5
2
3
4
EN
8-Pin MSOP (BMM)
MIC5245
Micrel
June 2000
3
MIC5245
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
2.0
3.0
%
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
100
150
A
I
OUT
= 150mA
100
A
PSRR
Power Supply Rejection
f = 120Hz, C
OUT
= 10
F, C
BYP
= 0.01
F
50
dB
I
LIM
Current Limit
V
OUT
= 0V
160
300
mA
e
n
Output Voltage Noise
C
OUT
= 10
F, C
BYP
= 0.01
F,
30
V(rms)
f = 10Hz to 100kHz
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
2.0
1
V
I
EN
Enable Input Current
V
IL
0.4V
0.17
A
V
IH
2.0V
1.5
A
Shutdown Resistance Discharge
500
Thermal Protection
Thermal Shutdown Temperature
150
C
Thermal Shutdown Hysteresis
10
C
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.
MIC5245
Micrel
MIC5245
4
June 2000
0
20
40
60
80
100
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
PSRR (dB)
FREQUENCY (Hz)
Power Supply
Rejection Ratio
I
OUT
= 100
A
C
OUT
= 1
F tant
V
IN
= 4V
V
OUT
= 3V
10
100
1k
10k 100k 1M 10M
0
20
40
60
80
100
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
PSRR (dB)
FREQUENCY (Hz)
Power Supply
Rejection Ratio
I
OUT
= 10mA
C
OUT
= 1
F tant
V
IN
= 4V
V
OUT
= 3V
10
100
1k
10k 100k 1M 10M
0
20
40
60
80
100
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
PSRR (dB)
FREQUENCY (Hz)
Power Supply
Rejection Ratio
I
OUT
= 100mA
C
OUT
= 1
F tant
V
IN
= 4V
V
OUT
= 3V
10
100
1k
10k 100k 1M 10M
0
20
40
60
80
100
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
PSRR (dB)
FREQUENCY (Hz)
Power Supply
Rejection Ratio
I
OUT
= 150mA
C
OUT
= 1
F tant
V
IN
= 4V
V
OUT
= 3V
10
100
1k
10k 100k 1M 10M
0
20
40
60
80
100
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
PSRR (dB)
FREQUENCY (Hz)
Power Supply
Rejection Ratio
I
OUT
= 100
A
C
OUT
= 10
F cer.
C
BYP
= 0.01
F
V
IN
= 4V
V
OUT
= 3V
10
100
1k
10k 100k 1M 10M
0
20
40
60
80
100
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
PSRR (dB)
FREQUENCY (Hz)
Power Supply
Rejection Ratio
I
OUT
= 10mA
C
OUT
= 10
F cer.
C
BYP
= 0.01
F
V
IN
= 4V
V
OUT
= 3V
10
100
1k
10k 100k 1M 10M
0
20
40
60
80
100
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
PSRR (dB)
FREQUENCY (Hz)
10
Power Supply
Rejection Ratio
I
OUT
= 100mA
C
OUT
= 10
F cer.
C
BYP
= 0.01
F
V
IN
= 4V
V
OUT
= 3V
100
1k
10k 100k 1M 10M
0
20
40
60
80
100
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
PSRR (dB)
FREQUENCY (Hz)
Power Supply
Rejection Ratio
I
OUT
= 150mA
C
OUT
= 10
F cer.
C
BYP
= 0.01
V
IN
= 4V
V
OUT
= 3V
10
100
1k
10k 100k 1M 10M
0
10
20
30
40
50
60
70
80
0
200
400
600
800
1000
RIPPLE REJECTION (dB)
VOLTAGE DROP (mV)
Power Supply Ripple Rejection
vs. Voltage Drop
I
OUT
= 100mA
10mA
100
A
C
OUT
= 1
F
150mA
0
10
20
30
40
50
60
70
80
0
200
400
600
800
1000
RIPPLE REJECTION (dB)
VOLTAGE DROP (mV)
Power Supply Ripple Rejection
vs. Voltage Drop
I
OUT
= 100mA
10mA
100
A
C
OUT
= 10
F cer.
C
BYP
= 0.01
F
100mA
0.01
0.1
1
10
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6
NOISE (
V/
Hz)
FREQUENCY (Hz)
Noise Performance
10
100
1k
10k
100k
1M
I
L
= 100
A
V
IN
= 4V
V
OUT
= 3V
C
OUT
= 1
F cer.
C
BYP
= 0.01
F
0.01
0.1
1
10
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6
NOISE (
V/
Hz)
FREQUENCY (Hz)
Noise Performance
10
100
1k
10k
100k
1M
I
L
= 100
A
V
IN
= 4V
V
OUT
= 3V
C
OUT
= 10
F cer.
C
BYP
= 0.01
F
Typical Characteristics
MIC5245
Micrel
June 2000
5
MIC5245
85
90
95
0.1
1
10
100
500
QUIESCENT CURRENT (
A)
LOAD CURRENT (mA)
Ground Pin Current
V
IN
= 4V
V
OUT
= 3V
0
50
100
150
200
-40 -20
0
20
40
60
80 100
QUIESCENT CURRENT (
A)
TEMPERATURE (
C)
Ground Pin Current
V
IN
= 4V
V
OUT
= 3V
I
OUT
= 100
A
50
75
100
125
150
-40 -20
0
20
40
60
80 100
QUIESCENT CURRENT (
A)
TEMPERATURE (
C)
Ground Pin Current
V
IN
= 4V
V
OUT
= 3V
I
OUT
= 150mA
0
25
50
75
100
0
1
2
3
4
5
QUIESCENT CURRENT (
A)
INPUT VOLTAGE (V)
Ground Pin Current
V
OUT
= 3V
I
OUT
= 100
A
0
25
50
75
100
0
1
2
3
4
5
QUIESCENT CURRENT (
A)
INPUT VOLTAGE (V)
Ground Pin Current
V
OUT
= 3V
I
OUT
= 150mA
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0
1
2
3
4
5
OUTPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Dropout Characteristics
V
OUT
= 3V
R
L
= 30
R
L
= 30k
0
2
4
6
8
-40 -20 0 20 40 60 80 100120140
DROPOUT VOLTAGE (mV)
TEMPERATURE (
C)
Dropout Voltage
I
LOAD
= 100
A
0
50
100
150
200
250
300
-40 -20 0 20 40 60 80 100120140
DROPOUT VOLTAGE (mV)
TEMPERATURE (
C)
Dropout Voltage
I
L
= 150mA
0
50
100
150
200
250
300
0
25
50
75
100 125 150
DROPOUT VOLTAGE (mV)
OUTPUT CURRENT (mA)
Dropout Voltage
T
A
= 25
C
T
A
= -40
C
T
A
= 125
C
0
100
200
300
400
500
600
-40 -20 0 20 40 60 80 100120140
OUTPUT CURRENT (mA)
TEMPERATURE (
C)
Short Circuit Current
V
IN
= 3.5V
V
EN
= 3V
2.85
2.90
2.95
3.00
3.05
-50
0
50
100
150
OUTPUT VOLTAGE (V)
TEMPERATURE (
C)
Output Voltage
vs. Temperature
V
IN
= 4V
TYPICAL 3V DEVICE
I
LOAD
= 100
A
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