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MIC5271
Micrel
MIC5271
µ
Cap Negative Low-Dropout Regulator
General Description
The MIC5271 is a
µCap
100mA negative regulator in a
SOT-23-5 package. With better than 2% initial accuracy, this
regulator provides a very accurate supply voltage for applica-
tions that require a negative rail. The MIC5271 sinks 100mA
of output current at very low dropout voltage (600mV maxi-
mum at 100mA of output current).
The
µCap
regulator design is optimized to work with low-
value, low-cost ceramic capacitors. The output typically re-
quires only a 1µF capacitance for stability.
Designed for applications where small packaging and effi-
ciency are critical, the MIC5271 combines LDO design exper-
tise with IttyBitty
packaging to improve performance and
reduce power dissipation. Ground current is optimized to help
improve battery life in portable applications. The MIC5271
also includes a TTL-compatible enable pin, allowing the user
to put the part into a zero-current off-mode.
The MIC5271 is available in the SOT-23-5 package for space
saving applications and it is available with an adjustable
output.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
Stable with ceramic or tantalum capacitor
Positive and negative enable thresholds
Low dropout voltage: 500mV @ 100mA
Low ground current: 35µA @ load = 100µA
Tight initial accuracy:
±2%
Tight load and line regulation
Thermal shutdown
Current limiting
IttyBitty
SOT-23-5 packaging
Zero-current off-mode
Applications
•
•
•
•
•
GaAsFET bias
Portable cameras and video recorders
PDAs
Battery-powered equipment
Post-regulation of DC-DC converters
Ordering Information
Part Number
MIC5271BM5
MIC5271-3.0BM5
MIC5271-5.0BM5
Marking
L9AA
L930
L950
Voltage*
Adj.
–3.0V
–5.0V
Junction Temp. Range
–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
* For other voltage options, please contact Micrel Marketing.
Typical Application
Enable Input
5
4
ENABLE VOLTAGE (V)
MIC5271BM5
2
1
R1
R2
3
2
1
0
-1
-2
-3
-4
-5
-3
Regulator On
GND ADJ
EN
–IN
–OUT
3
Regulator Off
V
IN
–6.0V
5
4
V
OUT
–5.0V
Regulator On
1µF
10µF
-5 -7 -9 -11 -13 -15
SUPPLY VOLTAGE (V)
Regulator With Adjustable Output
IttyBitty is a registered 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
October 2003
1
MIC5271
MIC5271
Micrel
Pin Configuration
ADJ GND EN
3
2
1
L9AA
4
5
–OUT
–IN
MIC5271BM5
Adjustable Output Voltage
Pin Description
Pin Number
(Adj.)
1
2
3
4
5
Pin Name
EN
GND
ADJ
–OUT
–IN
Pin Function
Enable Input. TTL logic compatible enable input. Logic High = ON, Logic
Low or open = OFF.
Ground.
Adjustable (Input): Adjustable feedback output connects to resistor voltage
divider.
Negative Regulator Output.
Negative Supply Input.
MIC5271
2
October 2003
MIC5271
Micrel
Absolute Maximum Ratings
(Note 1)
Input Voltage (V
–IN
) ...................................... –20V to +0.3V
Enable Voltage (V
EN
) .................................... –20V to +20V
Power Dissipation (P
D
) ............................ Internally Limited
Junction Temperature (T
J
) ....................... –40°C to +125°C
Lead Temperature (soldering, 5 sec.) ....................... 260°C
Storage Temperature (T
S
) ....................... –65°C to +150°C
ESD Rating,
Note 3
Operating Ratings
(Note 2)
Input Voltage (V
IN
) ....................................... –16V to –3.3V
Enable Voltage (V
EN
) .................................... –16V to +16V
Junction Temperature (T
J
) ....................... –40°C to +125°C
Thermal Resistance (θ
JA
)
Note 4 .........................
235°C/W
Electrical Characteristics
(Note 5)
V
IN
= V
OUT
– 1.0V; C
OUT
= 4.7µF, I
OUT
= 100µA; T
J
= 25°C,
bold
values indicate –40°C
≤
T
J
≤
+125°C; unless noted.
Symbol
V
OUT
∆V
OUT
/∆T
∆V
OUT
/V
OUT
∆V
OUT
/V
OUT
V
IN
– V
OUT
Parameter
Output Voltage Accuracy
Output Voltage Temperature
Coefficient
Line Regulation
Load Regulation
Dropout Voltage,
Note 8
Condition
Variation from nominal V
OUT
Note 6
V
IN
= V
OUT
– 1V to –16V
I
OUT
= 100µA to 100mA,
Note 7
I
OUT
= 100µA
I
OUT
= 50mA
I
OUT
= 100mA
I
GND
Ground Current,
Note 9
I
OUT
= 100µA
I
OUT
= 50mA
I
OUT
= 100mA
I
GND_SD
PSRR
I
LIMIT
Enable Input
T
ON
V
EN
I
EN
Note 1.
Note 2.
Note 3.
Note 4.
Min
–2
–3
Typ
Max
2
3
Units
%
%
ppm/°C
100
0.04
0.4
55
360
500
25
0.9
2.0
–1.0
0.1
50
235
350
3.0
+1.0
500
700
900
100
0.15
0.2
1.8
2.0
%/V
%
%
mV
mV
mV
µA
mA
mA
µA
dB
mA
Ground current in shutdown
Ripple Rejection
Current Limit
V
EN
=
±0.6V
f = 120Hz
V
OUT
= 0V
Time to V
OUT
= 90% nom.
Regulator OFF
Regulator ON
V
EN
=
±
0.6V and –2.0V
V
EN
= +2.0V
Turn-on Time
Input Low voltage
Input High Voltage
Enable Input Current
60
±0.6
±2.0
5.6
0.1
10.0
µs
V
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.
The maximum allowable power dissipation is a function of the maximum junction temperature, T
J(max)
, the junction-to-ambient thermal
resistance,
θ
JA
, and the ambient temperature, T
A
. The maximum allowable power dissipation at any ambient temperature is calculated using:
P
D(max)
= (T
J(max)
– T
A
) /
θ
JA
, where
θ
JA
is 235°C/W. Exceeding the maximum allowable power dissipation will result in excessive die
temperature, and the regulator will go into thermal shutdown. See the
“Thermal Considerations”
section for details.
Specification for packaged product only.
Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load
range from 100µA to 100mA. 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.
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.
Note 5.
Note 6.
Note 7.
Note 8.
Note 9.
October 2003
3
MIC5271
MIC5271
Micrel
Typical Characteristics
Dropout
Characteristics
OUTPUT VOLTAGE (V)
-3.5
OUTPUT VOLTAGE (V)
-3.305
-3.3
-3.295
-3.29
-3.285
-3.28
-3.275
-3.27
-3.265
-5
-3.26
0
Output Voltage
vs. Output Current
OUTPUT VOLTAGE (V)
-3.4
-3.38
-3.36
-3.34
-3.32
-3.3
-3.28
-3.26
-3.24
Output Voltage
vs. Temperature
-3
-2.5
-2
-1.5
-1
-0.5
0
0
0 Load
-100mA Load
-1
-2
-3
-4
SUPPLY VOLTAGE (V)
-20
-40
-60
-80 -100
OUTPUT CURRENT (mA)
-3.22
-3.2
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
-2.5
Ground Current
vs. Output Current
GROUND CURRENT (µA)
-90
-80
-70
-60
Ground Current
Characteristics
GROUND CURRENT (mA)
-1mA Load
-2.5
Ground Current
Characteristics
GROUND CURRENT (mA)
-2
-1.5
-1
-0.5
5V
IN
0
0
-20
-40
-60
-80 -100
OUTPUT CURRENT (mA)
-2 -100mA Load
-1.5
-50mA Load
-1
-0.5
0
0
-10mA Load
-50 -100µA Load
-40
-30
-20
-10
0
0
0µA Load
-1
-2
-3
-4
SUPPLY VOLTAGE (V)
-5
-1
-2
-3
-4
SUPPLY VOLTAGE (V)
-5
-30
GROUND CURRENT (µA)
Ground Current
vs. Temperature
GROUND CURRENT (µA)
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
Ground Current
vs. Temperature
ENABLE THRESHOLD (V)
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
Positive Enable Threshold
vs. Supply Voltage
Enable On
-1mA Load
-25
-20
-15
-10
-5
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
0A Load
-100mA Load
Enable Off
-50A Load
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
0
-4
-7
-10
-13
SUPPLY VOLTAGE (V)
-16
-1.6
Negative Enable Threshold
vs. Supply Voltage
DROPOUT VOLTAGE (mV)
-600
-500
-400
-300
-200
-100
0
0
Dropout
vs. Output Current
DROPOUT VOLTAGE (mV)
-400
-350
-300
-250
-200
-150
-100
-50
Dropout
vs. Temperature
-10mA Load
ENABLE THRESHOLD (V)
-1.4
-1.2
-1
-0.8
-0.6
-0.4
-0.2
0
-4
Enable On
Enable Off
0A Load
-7
-10
-13
SUPPLY VOLTAGE (V)
-16
-20
-40
-60
-80 -100
OUTPUT CURRENT (mA)
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
MIC5271
4
October 2003
嵌入式系统
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