MIC5245
Micrel
MIC5245
150mA
µ
Cap CMOS LDO Regulator
Final Information
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 100µA). 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 IttyBitty™ SOT-23-5
and power MSO-8 packages, the MIC5245 also offers a
range of fixed output voltages.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Ultralow dropout—100mV @ 100mA
Ultralow noise—30µV(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
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
Not recommended for new designs, see MIC5255.
Ordering Information
Part Number
MIC5245-2.5BM5
MIC5245-2.7BM5
MIC5245-2.8BM5
MIC5245-2.85BM5
MIC5245-3.0BM5
MIC5245-3.1BM5
MIC5245-3.2BM5
MIC5245-3.3BM5
MIC5245-3.3BMM
Marking
LS25
LS27
LS28
LS2J
LS30
LS31
LS32
LS33
—
Voltage
2.5V
2.7V
2.8V
2.85V
3.0V
3.1V
3.2V
3.3V
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
–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
SOT-23-5
SOT-23-5
MSOP-8
Other voltages available. Contact Micrel for details.
Typical Application
V
IN
MIC5245-x.xBM5
1
2
Enable
Shutdown
3
4
5
V
OUT
C
OUT
ENABLE
SHUTDOWN
MIC5245-3.3MM
1
2
3
4
8
7
6
5
V
IN
V
OUT
EN
EN (pin 3) may be
connected directly
o IN (pin 1).
C
BYP
(optional)
C
BYP
C
OUT
(OPTIONAL)
Ultra-Low-Noise Regulator Application
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
August 2002
1
MIC5245
MIC5245
Micrel
Pin Configuration
EN GND IN
3
2
1
EN 1
IN 2
OUT 3
8 GND
7 GND
6 GND
5 GND
LSxx
4
5
BYP
OUT
BYP 4
MIC5245-x.xBM5
8-Pin MSOP (BMM)
Pin Description
Pin Number
Power MOS-8
2
5–8
1
4
3
Pin Number
SOT-23
1
2
3
4
5
Pin Name
IN
GND
EN
BYP
OUT
Pin Function
Supply Input
Ground
Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;
logic low = shutdown. Do not leave open.
Reference Bypass: Connect external 0.01µF capacitor to GND to reduce
output noise. May be left open.
Regulator Output
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
(θ
JA
) .....................................................235°C/W
MSOP-8
(θ
JA
) ......................................................80°C/W
MIC5245
2
August 2002
MIC5245
Micrel
Electrical Characteristics
(Note 7)
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
e
n
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
≥
2.0V
Shutdown Resistance Discharge
Thermal Protection
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
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.
Specification for packaged product only.
Min
–1
–2
–0.3
Typical
Max
1
2
Units
%
%
%/V
%
mV
mV
mV
mV
mV
µA
µA
µA
dB
mA
µV(rms)
0
2.0
1.5
50
100
150
0.2
100
100
50
0.3
3.0
5
85
150
200
250
1
150
Quiescent Current
Ground Pin Current,
Note 6
V
EN
≤
0.4V (shutdown)
I
OUT
= 0mA
I
OUT
= 150mA
f = 120Hz, C
OUT
= 10µF, C
BYP
= 0.01µF
V
OUT
= 0V
C
OUT
= 10µF, C
BYP
= 0.01µF,
f = 10Hz to 100kHz
160
Power Supply Rejection
Current Limit
Output Voltage Noise
300
30
0.8
2.0
1
0.17
1.5
500
0.4
V
V
µA
µA
Ω
°C
°C
150
10
Note 6.
Note 7.
August 2002
3
MIC5245
MIC5245
Micrel
Typical Characteristics
Power Supply
Rejection Ratio
100
I
OUT
= 100µA
C
OUT
= 1µF tant
80
PSRR (dB)
60
40
20
0
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
V
IN
= 4V
V
OUT
= 3V
PSRR (dB)
100
I
OUT
= 10mA
80 C
OUT
= 1µF tant
60
40
20
0
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
V
IN
= 4V
V
OUT
= 3V
Power Supply
Rejection Ratio
100
Power Supply
Rejection Ratio
I
OUT
= 100mA
C
OUT
= 1µF tant
80
PSRR (dB)
60
40
20
0
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
V
IN
= 4V
V
OUT
= 3V
Power Supply
Rejection Ratio
100
I
OUT
= 150mA
80 C
OUT
= 1µF tant
PSRR (dB)
60
40
20
0
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
V
IN
= 4V
V
OUT
= 3V
PSRR (dB)
100
80
Power Supply
Rejection Ratio
100
80
PSRR (dB)
60
40
20
Power Supply
Rejection Ratio
V
IN
= 4V
V
OUT
= 3V
60
40
I
OUT
= 100µA
20 V = 4V
C
OUT
= 10µF cer.
IN
V
OUT
= 3V
C
BYP
= 0.01µF
0
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
I
OUT
= 10mA
C
OUT
= 10µF cer.
C
BYP
= 0.01µF
0
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
Power Supply
Rejection Ratio
100
80
PSRR (dB)
60
40
20
I
OUT
= 100mA
C
OUT
= 10µF cer.
C
BYP
= 0.01µF
V
IN
= 4V
V
OUT
= 3V
PSRR (dB)
100
80
60
40
20
Power Supply
Rejection Ratio
RIPPLE REJECTION (dB)
V
IN
= 4V
V
OUT
= 3V
Power Supply Ripple Rejection
vs. Voltage Drop
80
70
60
50
40
30
20
10
0
0
150mA
I
OUT
= 100mA
C
OUT
= 1µF
200 400 600 800 1000
VOLTAGE DROP (mV)
100µA
10mA
I
OUT
= 150mA
C
OUT
= 10µF cer.
C
BYP
= 0.01
0
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
0
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6
10M
10 100 1k 10k 100k 1M
1E+7
FREQUENCY (Hz)
Power Supply Ripple Rejection
vs. Voltage Drop
80
RIPPLE REJECTION (dB)
70
60
50
40
30
20
10
0
0
100µA
C
OUT
= 10µF cer.
C
BYP
= 0.01µF
200 400 600 800 1000
VOLTAGE DROP (mV)
10mA
100mA
I
OUT
= 100mA
Noise Performance
10
I
L
= 100µA
NOISE (µV/√Hz)
1
NOISE (µV/√Hz)
1
10
Noise Performance
I
L
= 100µA
V
IN
= 4V
0.1 V
OUT
= 3V
C
OUT
= 1µF cer.
C
BYP
= 0.01µF
0.01
10
100
1k 10k
1E+5
1M
1E+1 1E+2 1E+3 1E+4
100k
1E+6
FREQUENCY (Hz)
V
IN
= 4V
0.1 V
OUT
= 3V
C
OUT
= 10µF cer.
C
BYP
= 0.01µF
0.01
1k 10k 100k 1M
10
100
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6
FREQUENCY (Hz)
MIC5245
4
August 2002
MIC5245
Micrel
Ground Pin Current
95
QUIESCENT CURRENT (µA)
V
IN
= 4V
V
OUT
= 3V
QUIESCENT CURRENT (µA)
200
Ground Pin Current
V
IN
= 4V
V
OUT
= 3V
150
90
100
50
I
OUT
= 100µA
0
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
85
0.1
1
10
100
LOAD CURRENT (mA)
500
Ground Pin Current
150
QUIESCENT CURRENT (µA)
V
IN
= 4V
V
OUT
= 3V
QUIESCENT CURRENT (µA)
100
Ground Pin Current
100
V
OUT
= 3V
75
QUIESCENT CURRENT (µA)
Ground Pin Current
V
OUT
= 3V
75
125
100
50
50
75
I
OUT
= 150mA
50
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
25
I
OUT
= 100µA
0
0
1
2
3
4
INPUT VOLTAGE (V)
5
25
I
OUT
= 150mA
1
2
3
4
INPUT VOLTAGE (V)
5
0
0
Dropout Characteristics
3.5
DROPOUT VOLTAGE (mV)
OUTPUT VOLTAGE (V)
3.0
2.5
2.0
1.5
1.0
0.5
0
0
1
2
3
4
INPUT VOLTAGE (V)
5
V
OUT
= 3V
R
L
= 30kΩ
R
L
= 30Ω
8
Dropout Voltage
300
I
LOAD
= 100µA
6
DROPOUT VOLTAGE (mV)
250
200
150
100
50
Dropout Voltage
I
L
= 150mA
4
2
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
Dropout Voltage
300
DROPOUT VOLTAGE (mV)
250
200
150
100
50
0
0
T
A
= -40°C
25 50 75 100 125 150
OUTPUT CURRENT (mA)
T
A
= 125°C
T
A
= 25°C
OUTPUT CURRENT (mA)
600
500
400
300
200
100
Short Circuit Current
3.05
OUTPUT VOLTAGE (V)
Output Voltage
vs. Temperature
V
IN
= 4V
TYPICAL 3V DEVICE
3.00
V
IN
= 3.5V
V
EN
= 3V
2.95
2.90
I
LOAD
= 100µA
2.85
-50
0
50
100
TEMPERATURE (°C)
150
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
August 2002
5
MIC5245
嵌入式系统
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