MIC5247
Micrel
MIC5247
150mA Low-Voltage
µ
Cap Linear Regulator
Preliminary Information
General Description
The MIC5247 is an efficient, precise low voltage CMOS
voltage regulator optimized for ultra-low-noise applications.
The MIC5247 offers better than 1% initial accuracy, and 85µA
constant ground current over load (typically 85µA). The
MIC5247 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 MIC5247 provides a logic compatible enable pin.
When disabled, power consumption drops nearly to zero.
The MIC5247 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 MIC5247 also offers a range of fixed output
voltages.
Features
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Ultralow noise
Low voltage outputs
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
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
MIC5247-1.5BM5
MIC5247-1.8BM5
MIC5247-2.0BM5
MIC5247-2.4BM5
Marking
LU15
LU18
LU20
LU24
Voltage
1.5V
1.8V
2.0V
2.4V
Junction Temp. Range
–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
Other voltages available. Contact Micrel for details.
Typical Application
V
IN
MIC5247-x.xBM5
1
2
Enable
Shutdown
3
4
5
V
OUT
C
OUT
EN
EN (pin 3) may be
connected directly
to IN (pin 1).
C
BYP
(optional)
Ultra-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
November 6, 2000
1
MIC5247
MIC5247
Micrel
Pin Configuration
EN GND IN
3
2
1
LUxx
4
5
BYP
OUT
MIC5247-x.xBM5
Pin Description
Pin Number
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 0.01pF 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 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
Junction Temperature (T
J
) ....................... –40°C to +125°C
Thermal Resistance
(θ
JA
)...................................... 235°C/W
MIC5247
2
November 6, 2000
MIC5247
Micrel
Electrical Characteristics
V
IN
= V
OUT
+ 1.0V; V
IN
= V
EN
; 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
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
≥
1.6V
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 a1V
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 plus pass transistor base current. The total current drawn from the supply is the sum of
the load current plus the ground pin current.
Parameter
Output Voltage Accuracy
Line Regulation
Load Regulation
Load Regulation for 1.5V only
Dropout Voltage
Quiescent Current
Ground Pin Current,
Note 6
Conditions
I
OUT
= 0mA
V
IN
= V
OUT
+ 0.1V to 6V
I
OUT
= 0.1mA to 150mA,
Note 4
I
OUT
= 0.1mA to 150mA, V
OUT
= 1.5V
I
OUT
= 150mA (see Note 5)
V
EN
≤
0.4V (shutdown)
I
OUT
= 0mA
I
OUT
= 150mA
f
≤
1kHz
V
OUT
= 0V
C
OUT
= 10µF, C
BYP
= 0.01µF,
f = 10Hz to 100kHz
Min
–1
–2
–0.3
Typical
Max
1
2
+0.3
Units
%
%
%/V
%
%
mV
µA
µA
µA
dB
mA
µVrms
2
3
150
0.2
85
85
50
160
300
30
3
4
1
150
150
Power Supply Rejection
Current Limit
Output Voltage Noise
0.8
1.6
1
0.01
0.01
500
0.4
V
V
µA
µA
Ω
°C
°C
150
10
Note 6.
November 6, 2000
3
MIC5247
MIC5247
Micrel
Typical Characteristics
Power Supply Rejection Ratio
90
80 C
BYP
= 1µF
70
PSRR (dB)
PSRR (dB)
Power Supply Rejection Ratio
70
1µF
Power Supply Rejection Ratio
60
50
PSRR (dB)
C
BYP
= 0.01µF
0.01µF
1µF
60
50 0.01µF
40
30
C
BYP
= 0
I
L
= 50mA
20 V = 3.4V
IN
10 V
OUT
= 2.4V
C
OUT
=10µF Ceramic
0
1x10
1
1x10
2
1x10
3
60 C
=0
BYP
50
40
30
20
10
1x10
1
1x10
2
40
30
C
BYP
= 0
I
L
= 100µA
V
IN
= 3.4V
V
OUT
= 2.4V
C
= 10µF Ceramic
OUT
1x10
4
1x10
5
1x10
6
1x10
1
1x10
2
1x10
3
1x10
4
1x10
5
1x10
2
1x10
3
1x10
4
1x10
5
FREQUENCY (Hz)
1x10
6
FREQUENCY (Hz)
FREQUENCY (Hz)
Power Supply Rejection Ratio
60
50
1µF
PSRR (dB)
OUTPUT SPECTRAL NOISE DENSITY (µV/rt Hz)
Noise Performance
75
GROUND CURRENT (µA)
Ground Current
vs. Output Current
0.01µF
1x10
-5
C
BYP
= 0
1x10
-6
74
73
72
71
70
40
30
C
BYP
= 0
1x10
0
1x10
1
1x10
1
1x10
2
1x10
3
1x10
4
1x10
5
1x10
6
1x10
1
1x10
2
1x10
3
1x10
4
1x10
5
1x10
6
1x10
-8
1x10
-1
OUTPUT CURRENT (mA)
FREQUENCY (Hz)
FREQUENCY (Hz)
Ground Pin Current
100
GROUND CURRENT (µA)
GROUND CURRENT (µA)
80
60
40
20
I
LOAD
= 100µA
0
-40 -10 20 50 80 110 140
TEMPERATURE (°C)
100
80
60
40
20
Ground Pin Current
100
GROUND CURRENT (µA)
80
60
40
20
Ground Pin Current
I
LOAD
= 150mA
0
-40
-10 20 50 80 110 140
TEMPERATURE (°C)
I
LOAD
= 100µA
0
0
1
2
3
INPUT VOLTAGE (V)
4
Ground Pin Current
100
GROUND CURRENT (µA)
80
60
40
20
I
LOAD
= 150mA
0
0
1
2
3
INPUT VOLTAGE (V)
4
0
0
3
Dropout Characteristics
SHORT CIRCUIT CURRENT (mA)
500
400
300
200
100
Short Circuit Current
vs. Temperature
VOLTAGE OUT (V)
I
LOAD
= 100µA
2
I
LOAD
=
150mA
1
1
2
3
INPUT VOLTAGE (V)
4
VOUT = 0
0
-40 -10 20 50 80 110 140
TEMPERATURE (°C)
MIC5247
4
November 6, 2000
1x10
3
20 I
L
= 150mA
V
IN
= 3.4V
10 V
OUT
= 2.4V
C
OUT
= 10µF Ceramic
0
1x10
-7
C
BYP
= 0.01µF
V
IN
= 2.8V
V
OUT
= 1.8V
C
OUT
= 4.7µF
V
IN
= V
OUT
+ 1
I
LOAD
= 50mA
1x10
6
0
20 I
L
= 100mA
V
IN
= 3.4V
10 V
= 2.4V
OUT
C
OUT
= 10µF Ceramic
0
MIC5247
Micrel
Output Voltage
vs. Temperature
2.5
OUTPUT VOLTAGE (V)
Turn-On Time
vs. Bypass Capacitance
200
C
OUT
= 10µF
I
LOAD
= 100mA
150
TIME (µs)
I
LOAD
= 100µA
1x10
0
1x10
-5
1x10
-4
1x10
-3
1x10
-2
-10 20 50 80 110 140
TEMPERATURE (°C)
1x10
-1
1x10
1
2.3
-40
2.4
100
Rise Time
50
Prop Delay
0
BYPASS CAPACITOR (µF)
November 6, 2000
5
MIC5247
嵌入式系统
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