LM4132
LM4132 SOT-23 Precision Low Dropout Voltage Reference
Literature Number: SNVS372B
LM4132
SOT-23 Precision Low Dropout Voltage Reference
General Description
The LM4132 family of precision voltage references performs
comparable to the best laser-trimmed bipolar references, but
in cost effective CMOS technology. The key to this break
through is the use of EEPROM registers for correction of
curvature, tempco, and accuracy on a CMOS bandgap ar-
chitecture that allows package level programming to over-
come assembly shift. The shifts in voltage accuracy and
tempco during assembly of die into plastic packages limit the
accuracy of references trimmed with laser techniques.
Unlike other LDO references, the LM4132 is capable of
delivering up to 20mA and does not require an output ca-
pacitor or buffer amplifier. These advantages and the SOT23
packaging are important for space-critical applications.
Series references provide lower power consumption than
shunt references, since they do not have to idle the maxi-
mum possible load current under no load conditions. This
advantage, the low quiescent current (60µA), and the low
dropout voltage (400mV) make the LM4132 ideal for battery-
powered solutions.
The LM4132 is available in five grades (A, B, C, D and E) for
greater flexibility. The best grade devices (A) have an initial
accuracy of 0.05% with guaranteed temperature coefficient
of 10ppm/˚C or less, while the lowest grade parts (E) have
an initial accuracy of 0.5% and a tempco of 30ppm/˚C.
Features
nOutput initial voltage accuracy 0.05%
nLow temperature coefficient 10ppm/˚C
nLow Supply Current, 60µA
nEnable pin allowing a 3µA shutdown mode
n20mA output current
nVoltage options 1.8V, 2.048V, 2.5V, 3.0V, 3.3V, 4.096V
nCustom voltage options available (1.8V to 4.096V)
nV
IN
range of V
REF
+ 400mV to 5.5V @10mA
nStable with low ESR ceramic capacitors
nSOT23-5 Package
Applications
nInstrumentation & Process Control
nTest Equipment
nData Acquisition Systems
nBase Stations
nServo Systems
nPortable, Battery Powered Equipment
nAutomotive & Industrial
nPrecision Regulators
nBattery Chargers
nCommunications
nMedical Equipment
Typical Application Circuit
20151301
*Note: The capacitor CIN is required and the capacitor COUT is optional.
August 2006
LM4132 SOT-23 Precision Low Dropout Voltage Reference
© 2006 National Semiconductor Corporation DS201513 www.national.com
Connection Diagram
Top View
20151302
SOT23-5 Package
NS Package Number MF05A
Ordering Information
Input Output Voltage Accuracy at
25˚C And Temperature Coefficient
LM4132 Supplied as 1000
units, Tape and Reel
LM4132 Supplied as 3000 units,
Tape and Reel Part Marking
0.05%, 10 ppm/˚C max (A grade) LM4132AMF-1.8 LM4132AMFX-1.8 R4AA
LM4132AMF-2.0 LM4132AMFX-2.0 R4BA
LM4132AMF-2.5 LM4132AMFX-2.5 R4CA
LM4132AMF-3.0 LM4132AMFX-3.0 R4DA
LM4132AMF-3.3 LM4132AMFX-3.3 R4EA
LM4132AMF-4.1 LM4132AMFX-4.1 R4FA
0.1%, 20 ppm/˚C max (B grade) LM4132BMF-1.8 LM4132BMFX-1.8 R4AB
LM4132BMF-2.0 LM4132BMFX-2.0 R4BB
LM4132BMF-2.5 LM4132BMFX-2.5 R4CB
LM4132BMF-3.0 LM4132BMFX-3.0 R4DB
LM4132BMF-3.3 LM4132BMFX-3.3 R4EB
LM4132BMF-4.1 LM4132BMFX-4.1 R4FB
0.2%, 20 ppm/˚C max (C grade) LM4132CMF-1.8 LM4132CMFX-1.8 R4AC
LM4132CMF-2.0 LM4132CMFX-2.0 R4BC
LM4132CMF-2.5 LM4132CMFX-2.5 R4CC
LM4132CMF-3.0 LM4132CMFX-3.0 R4DC
LM4132CMF-3.3 LM4132CMFX-3.3 R4EC
LM4132CMF-4.1 LM4132CMFX-4.1 R4FC
0.4%, 20 ppm/˚C max (D grade) LM4132DMF-1.8 LM4132DMFX-1.8 R4AD
LM4132DMF-2.0 LM4132DMFX-2.0 R4BD
LM4132DMF-2.5 LM4132DMFX-2.5 R4CD
LM4132DMF-3.0 LM4132DMFX-3.0 R4DD
LM4132DMF-3.3 LM4132DMFX-3.3 R4ED
LM4132DMF-4.1 LM4132DMFX-4.1 R4FD
0.5%, 30 ppm/˚C max (E grade) LM4132EMF-1.8 LM4132EMFX-1.8 R4AE
LM4132EMF-2.0 LM4132EMFX-2.0 R4BE
LM4132EMF-2.5 LM4132EMFX-2.5 R4CE
LM4132EMF-3.0 LM4132EMFX-3.0 R4DE
LM4132EMF-3.3 LM4132EMFX-3.3 R4EE
LM4132EMF-4.1 LM4132EMFX-4.1 R4FE
Pin Descriptions
Pin # Name Function
1 N/C No connect pin, leave floating
2 GND Ground
3 EN Enable pin
4V
IN
Input supply
5V
REF
Reference output
LM4132
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Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Maximum Voltage on any input -0.3 to 6V
Output short circuit duration Indefinite
Power Dissipation (T
A
= 25˚C)
(Note 2) 350mW
Storage Temperature Range −65˚C to 150˚C
Lead Temperature (soldering, 10sec) 260˚C
Vapor Phase (60 sec) 215˚C
Infrared (15sec) 220˚C
ESD Susceptibility (Note 3)
Human Body Model 2kV
Operating Ratings
Maximum Input Supply Voltage 5.5V
Maximum Enable Input Voltage V
IN
Maximum Load Current 20mA
Junction Temperature Range (T
J
) −40˚C to
+125˚C
Electrical Characteristics
LM4132-1.8 (V
OUT
= 1.8V) Limits in standard type are for T
J
= 25˚C only, and limits in boldface type apply
over the junction temperature (T
J
) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are
guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at T
J
=
25˚C, and are provided for reference purposes only. Unless otherwise specified V
IN
= 5V and I
LOAD
=0
Symbol Parameter Conditions
Min
(Note 4)
Typ
(Note
5)
Max
(Note 4) Unit
V
REF
Output Voltage Initial Accuracy
LM4132A-1.8 (A Grade - 0.05%) -0.05 0.05 %
LM4132B-1.8 (B Grade - 0.1%) -0.1 0.1
LM4132C-1.8 (C Grade - 0.2%) -0.2 0.2
LM4132D-1.8 (D Grade - 0.4%) -0.4 0.4
LM4132E-1.8 (E Grade - 0.5%) -0.5 0.5
TCV
REF
/˚C
(Note 6)
Temperature Coefficient
LM4132A-1.8 0˚C ≤T
J
≤+ 85˚C 10
ppm/˚C
-40˚C ≤T
J
≤+125˚C 20
LM4132B-1.8
-40˚C ≤T
J
≤+125˚C
20
LM4132C-1.8 20
LM4132D-1.8 20
LM4132E-1.8 30
I
Q
Supply Current 60 100 µA
I
Q_SD
Supply Current in Shutdown EN = 0V 3 7µA
∆V
REF
/∆V
IN
Line Regulation V
REF
+ 400mV ≤V
IN
≤5.5V 30 ppm / V
∆V
REF
/∆I
LOAD
Load Regulation 0mA ≤I
LOAD
≤20mA 25 120 ppm/mA
∆V
REF
Long Term Stability (Note 7) 1000 Hrs 50 ppm
Thermal Hysteresis (Note 8) -40˚C ≤T
J
≤+125˚C 75
V
IN
-V
REF
Dropout Voltage (Note 9) I
LOAD
= 10mA 230 400 mV
V
N
Output Noise Voltage 0.1 Hz to 10 Hz 170 µV
PP
I
SC
Short Circuit Current 75 mA
V
IL
Enable Pin Maximum Low Input
Level
35 %V
IN
V
IH
Enable Pin Minimum High Input
Level
65 %V
IN
LM4132
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Electrical Characteristics
LM4132-2.0 (V
OUT
= 2.048V) Limits in standard type are for T
J
= 25˚C only, and limits in boldface type ap-
ply over the junction temperature (T
J
) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are
guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at T
J
=
25˚C, and are provided for reference purposes only. Unless otherwise specified V
IN
= 5V and I
LOAD
=0
Symbol Parameter Conditions
Min
(Note 4)
Typ
(Note
5)
Max
(Note 4) Unit
V
REF
Output Voltage Initial Accuracy
LM4132A-2.0 (A Grade - 0.05%) -0.05 0.05 %
LM4132B-2.0 (B Grade - 0.1%) -0.1 0.1
LM4132C-2.0 (C Grade - 0.2%) -0.2 0.2
LM4132D-2.0 (D Grade - 0.4%) -0.4 0.4
LM4132E-2.0 (E Grade - 0.5%) -0.5 0.5
TCV
REF
/˚C
(Note 6)
Temperature Coefficient
LM4132A-2.0 0˚C ≤T
J
≤+ 85˚C 10
ppm/˚C
-40˚C ≤T
J
≤+125˚C 20
LM4132B-2.0
-40˚C ≤T
J
≤+125˚C
20
LM4132C-2.0 20
LM4132D-2.0 20
LM4132E-2.0 30
I
Q
Supply Current 60 100 µA
I
Q_SD
Supply Current in Shutdown EN = 0V 3 7µA
∆V
REF
/∆V
IN
Line Regulation V
REF
+ 400mV ≤V
IN
≤5.5V 30 ppm / V
∆V
REF
/∆I
LOAD
Load Regulation 0mA ≤I
LOAD
≤20mA 25 120 ppm/mA
∆V
REF
Long Term Stability (Note 7) 1000 Hrs 50 ppm
Thermal Hysteresis (Note 8) -40˚C ≤T
J
≤+125˚C 75
V
IN
-V
REF
Dropout Voltage (Note 9) I
LOAD
= 10mA 175 400 mV
V
N
Output Noise Voltage 0.1 Hz to 10 Hz 190 µV
PP
I
SC
Short Circuit Current 75 mA
V
IL
Enable Pin Maximum Low Input
Level
35 %V
IN
V
IH
Enable Pin Minimum High Input
Level
65 %V
IN
LM4132
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Electrical Characteristics
LM4132-2.5 (V
OUT
= 2.5V) Limits in standard type are for T
J
= 25˚C only, and limits in boldface type apply
over the junction temperature (T
J
) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are
guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at T
J
=
25˚C, and are provided for reference purposes only. Unless otherwise specified V
IN
= 5V and I
LOAD
=0
Symbol Parameter Conditions
Min
(Note 4)
Typ
(Note 5)
Max
(Note 4) Unit
V
REF
Output Voltage Initial Accuracy
LM4132A-2.5 (A Grade - 0.05%) -0.05 0.05 %
LM4132B-2.5 (B Grade - 0.1%) -0.1 0.1
LM4132C-2.5 (C Grade - 0.2%) -0.2 0.2
LM4132D-2.5 (D Grade - 0.4%) -0.4 0.4
LM4132E-2.5 (E Grade - 0.5%) -0.5 0.5
TCV
REF
/˚C
(Note 6)
Temperature Coefficient
LM4132A-2.5 0˚C ≤T
J
≤+ 85˚C 10
ppm/˚C
-40˚C ≤T
J
≤+125˚C 20
LM4132B-2.5
-40˚C ≤T
J
≤+125˚C
20
LM4132C-2.5 20
LM4132D-2.5 20
LM4132E-2.5 30
I
Q
Supply Current 60 100 µA
I
Q_SD
Supply Current in Shutdown EN = 0V 3 7µA
∆V
REF
/∆V
IN
Line Regulation V
REF
+ 400mV ≤V
IN
≤5.5V 50 ppm / V
∆V
REF
/∆I
LOAD
Load Regulation 0mA ≤I
LOAD
≤20mA 25 120 ppm/mA
∆V
REF
Long Term Stability (Note 7) 1000 Hrs 50 ppm
Thermal Hysteresis (Note 8) -40˚C ≤T
J
≤+125˚C 75
V
IN
-V
REF
Dropout Voltage (Note 9) I
LOAD
= 10mA 175 400 mV
V
N
Output Noise Voltage 0.1 Hz to 10 Hz 240 µV
PP
I
SC
Short Circuit Current 75 mA
V
IL
Enable Pin Maximum Low Input
Level
35 %V
IN
V
IH
Enable Pin Minimum High Input
Level
65 %V
IN
LM4132
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Electrical Characteristics
LM4132-3.0 (V
OUT
= 3.0V) Limits in standard type are for T
J
= 25˚C only, and limits in boldface type apply
over the junction temperature (T
J
) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are
guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at T
J
=
25˚C, and are provided for reference purposes only. Unless otherwise specified V
IN
= 5V and I
LOAD
=0
Symbol Parameter Conditions
Min
(Note 4)
Typ
(Note 5)
Max
(Note 4) Unit
V
REF
Output Voltage Initial Accuracy
LM4132A-3.0 (A Grade - 0.05%) -0.05 0.05 %
LM4132B-3.0 (B Grade - 0.1%) -0.1 0.1
LM4132C-3.0 (C Grade - 0.2%) -0.2 0.2
LM4132D-3.0 (D Grade - 0.4%) -0.4 0.4
LM4132E-3.0 (E Grade - 0.5%) -0.5 0.5
TCV
REF
/˚C
(Note 6)
Temperature Coefficient
LM4132A-3.0 0˚C ≤T
J
≤+ 85˚C 10
ppm/˚C
-40˚C ≤T
J
≤+125˚C 20
LM4132B-3.0
-40˚C ≤T
J
≤+125˚C
20
LM4132C-3.0 20
LM4132D-3.0 20
LM4132E-3.0 30
I
Q
Supply Current 60 100 µA
I
Q_SD
Supply Current in Shutdown EN = 0V 3 7µA
∆V
REF
/∆V
IN
Line Regulation V
REF
+ 400mV ≤V
IN
≤5.5V 70 ppm / V
∆V
REF
/∆I
LOAD
Load Regulation 0mA ≤I
LOAD
≤20mA 25 120 ppm/mA
∆V
REF
Long Term Stability (Note 7) 1000 Hrs 50 ppm
Thermal Hysteresis (Note 8) -40˚C ≤T
J
≤+125˚C 75
V
IN
-V
REF
Dropout Voltage (Note 9) I
LOAD
= 10mA 175 400 mV
V
N
Output Noise Voltage 0.1 Hz to 10 Hz 285 µV
PP
I
SC
Short Circuit Current 75 mA
V
IL
Enable Pin Maximum Low Input
Level
35 %V
IN
V
IH
Enable Pin Minimum High Input
Level
65 %V
IN
LM4132
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Electrical Characteristics
LM4132-3.3 (V
OUT
= 3.3V) Limits in standard type are for T
J
= 25˚C only, and limits in boldface type apply
over the junction temperature (T
J
) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are
guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at T
J
=
25˚C, and are provided for reference purposes only. Unless otherwise specified V
IN
= 5V and I
LOAD
=0
Symbol Parameter Conditions
Min
(Note 4)
Typ
(Note 5)
Max
(Note 4) Unit
V
REF
Output Voltage Initial Accuracy
LM4132A-3.3 (A Grade - 0.05%) -0.05 0.05 %
LM4132B-3.3 (B Grade - 0.1%) -0.1 0.1
LM4132C-3.3 (C Grade - 0.2%) -0.2 0.2
LM4132D-3.3 (D Grade - 0.4%) -0.4 0.4
LM4132E-3.3 (E Grade - 0.5%) -0.5 0.5
TCV
REF
/˚C
(Note 6)
Temperature Coefficient
LM4132A-3.3 0˚C ≤T
J
≤+ 85˚C 10
ppm/˚C
-40˚C ≤T
J
≤+125˚C 20
LM4132B-3.3
-40˚C ≤T
J
≤+125˚C
20
LM4132C-3.3 20
LM4132D-3.3 20
LM4132E-3.3 30
I
Q
Supply Current 60 100 µA
I
Q_SD
Supply Current in Shutdown EN = 0V 3 7µA
∆V
REF
/∆V
IN
Line Regulation V
REF
+ 400mV ≤V
IN
≤5.5V 85 ppm / V
∆V
REF
/∆I
LOAD
Load Regulation 0mA ≤I
LOAD
≤20mA 25 120 ppm/mA
∆V
REF
Long Term Stability (Note 7) 1000 Hrs 50 ppm
Thermal Hysteresis (Note 8) -40˚C ≤T
J
≤+125˚C 75
V
IN
-V
REF
Dropout Voltage (Note 9) I
LOAD
= 10mA 175 400 mV
V
N
Output Noise Voltage 0.1 Hz to 10 Hz 310 µV
PP
I
SC
Short Circuit Current 75 mA
V
IL
Enable Pin Maximum Low Input
Level
35 %V
IN
V
IH
Enable Pin Minimum High Input
Level
65 %V
IN
LM4132
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Electrical Characteristics
LM4132-4.1 (V
OUT
= 4.096V) Limits in standard type are for T
J
= 25˚C only, and limits in boldface type ap-
ply over the junction temperature (T
J
) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are
guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at T
J
=
25˚C, and are provided for reference purposes only. Unless otherwise specified V
IN
= 5V and I
LOAD
=0
Symbol Parameter Conditions
Min
(Note 4)
Typ
(Note
5)
Max
(Note 4) Unit
V
REF
Output Voltage Initial Accuracy
LM4132A-4.1 (A Grade - 0.05%) -0.05 0.05 %
LM4132B-4.1 (B Grade - 0.1%) -0.1 0.1
LM4132C-4.1 (C Grade - 0.2%) -0.2 0.2
LM4132D-4.1 (D Grade - 0.4%) -0.4 0.4
LM4132E-4.1 (E Grade - 0.5%) -0.5 0.5
TCV
REF
/˚C
(Note 6)
Temperature Coefficient
LM4132A-4.1 0˚C ≤T
J
≤+ 85˚C 10
ppm/˚C
-40˚C ≤T
J
≤+125˚C 20
LM4132B-4.1
-40˚C ≤T
J
≤+125˚C
20
LM4132C-4.1 20
LM4132D-4.1 20
LM4132E-4.1 30
I
Q
Supply Current 60 100 µA
I
Q_SD
Supply Current in Shutdown EN = 0V 3 7µA
∆V
REF
/∆V
IN
Line Regulation V
REF
+ 400mV ≤V
IN
≤5.5V 100 ppm / V
∆V
REF
/∆I
LOAD
Load Regulation 0mA ≤I
LOAD
≤20mA 25 120 ppm/mA
∆V
REF
Long Term Stability (Note 7) 1000 Hrs 50 ppm
Thermal Hysteresis (Note 8) -40˚C ≤T
J
≤+125˚C 75
V
IN
-V
REF
Dropout Voltage (Note 9) I
LOAD
= 10mA 175 400 mV
V
N
Output Noise Voltage 0.1 Hz to 10 Hz 350 µV
PP
I
SC
Short Circuit Current 75 mA
V
IL
Enable Pin Maximum Low Input
Level
35 %V
IN
V
IH
Enable Pin Minimum High Input
Level
65 %V
IN
Note 1: Absolute Maximum Ratings indicate limits beyond which damage may occur to the device. Operating Ratings indicate conditions for which the device is
intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications, see Electrical Characteristics.
Note 2: Without PCB copper enhancements. The maximum power dissipation must be de-rated at elevated temperatures and is limited by TJMAX (maximum
junction temperature), θJ-A (junction to ambient thermal resistance) and TA(ambient temperature). The maximum power dissipation at any temperature is: PDissMAX
=(T
JMAX -T
A)/θJ-A up to the value listed in the Absolute Maximum Ratings. θJ-A for SOT23-5 package is 220˚C/W, TJMAX = 125˚C.
Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 kΩresistor into each pin.
Note 4: Limits are 100% production tested at 25˚C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control.
Note 5: Typical numbers are at 25˚C and represent the most likely parametric norm.
Note 6: Temperature coefficient is measured by the "Box" method; i.e., the maximum ∆VREF is divided by the maximum ∆T.
Note 7: Long term stability is VREF @25˚C measured during 1000 hrs.
Note 8: Thermal hysteresis is defined as the change in +25˚C output voltage before and after cycling the device from (-40˚C to 125˚C).
Note 9: Dropout voltage is defined as the minimum input to output differential at which the output voltage drops by 0.5% below the value measured with a 5V input.
LM4132
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Typical Performance Characteristics for 1.8V
Output Voltage vs Temperature Load Regulation
20151364 20151367
Line Regulation 0.1-10Hz Noise Spectrum
20151368
20151379
Output Voltage Noise Spectrum Power Supply Rejection vs Frequency
20151373 20151376
LM4132
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Typical Performance Characteristics for 2.048V
Output Voltage vs Temperature Load Regulation
20151303 20151304
Line Regulation 0.1 - 10 Hz Noise
20151309
20151314
Output Voltage Noise Spectrum Power Supply Rejection vs Frequency
20151340 20151315
LM4132
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Typical Performance Characteristics for 2.5V
Output Voltage vs Temperature Load Regulation
20151354 20151355
Line Regulation 0.1 - 10 Hz Noise
20151356
20151321
Output Voltage Noise Spectrum Power Supply Rejection vs Frequency
20151357 20151358
LM4132
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Typical Performance Characteristics for 3.0V
Output Voltage vs Temperature Load Regulation
20151365 20151369
Line Regulation 0.1-10 Hz Noise Spectrum
20151370
20151380
Output Voltage Noise Spectrum Power Supply Rejection vs Frequency
20151374 20151377
LM4132
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Typical Performance Characteristics for 3.3V
Output Voltage vs Temperature Load Regulation
20151366 20151371
Line Regulation 0.1-10 Hz Noise Spectrum
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20151381
Output Voltage Noise Spectrum Power Supply Rejection vs Frequency
20151375 20151378
LM4132
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Typical Performance Characteristics for 4.096V
Output Voltage vs Temperature Load Regulation
20151359 20151360
Line Regulation 0.1 - 10 Hz Noise
20151361
20151319
Output Voltage Noise Spectrum Power Supply Rejection vs Frequency
20151362 20151363
LM4132
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Typical Performance Characteristics
Dropout vs Load to 0.5% Accuracy Supply Current vs Input Voltage
20151308 20151353
Enable Threshold Voltage and Hysteresis Shutdown I
Q
vs Temperature
20151317
20151310
Typical Long Term Stability Ground Current vs Load Current
20151330
20151318
LM4132
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Typical Performance Characteristics (Continued)
Typical Thermal Hysteresis Turn-On Transient Response
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20151352
Load Transient Response
I
LOAD
= 0 to 10mA
Line Transient Response
V
IN
= 4V to 5.5V
20151350 20151351
LM4132
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Application Information
THEORY OF OPERATION
The foundation of any voltage reference is the band-gap
circuit. While the reference in the LM4132 is developed from
the gate-source voltage of transistors in the IC, principles of
the band-gap circuit are easily understood using a bipolar
example. For a detailed analysis of the bipolar band-gap
circuit, please refer to Application Note AN-56.
SUPPLY AND ENABLE VOLTAGES
To ensure proper operation, V
EN
and V
IN
must be within a
specified range. An acceptable range of input voltages is
V
IN
>V
REF
+ 400mV (I
LOAD
≤10mA)
The enable pin uses an internal pull-up current source (I
P-
ULL_UP
)2µA) that may be left floating or triggered by an
external source. If the part is not enabled by an external
source, it may be connected to V
IN
. An acceptable range of
enable voltages is given by the enable transfer characteris-
tics. See the Electrical Characteristics section and Enable
Transfer Characteristics figure for more detail. Note, the part
will not operate correctly for V
EN
>V
IN
.
COMPONENT SELECTION
A small ceramic (X5R or X7R) capacitor on the input must be
used to ensure stable operation. The value of C
IN
must be
sized according to the output capacitor value. The value of
C
IN
must satisfy the relationship C
IN
≥C
OUT
. When no output
capacitor is used, C
IN
must have a minimum value of 0.1µF.
Noise on the power-supply input may affect the output noise.
Larger input capacitor values (typically 4.7µF to 22µF) may
help reduce noise on the output and significantly reduce
overshoot during startup. Use of an additional optional by-
pass capacitor between the input and ground may help
further reduce noise on the output. With an input capacitor,
the LM4132 will drive any combination of resistance and
capacitance up to V
REF
/20mA and 10µF respectively.
The LM4132 is designed to operate with or without an output
capacitor and is stable with capacitive loads up to 10µF.
Connecting a capacitor between the output and ground will
significantly improve the load transient response when
switching from a light load to a heavy load. The output
capacitor should not be made arbitrarily large because it will
effect the turn-on time as well as line and load transients.
While a variety of capacitor chemistry types may be used, it
is typically advisable to use low esr ceramic capacitors. Such
capacitors provide a low impedance to high frequency sig-
nals, effectively bypassing them to ground. Bypass capaci-
tors should be mounted close to the part. Mounting bypass
capacitors close to the part will help reduce the parasitic
trace components thereby improving performance.
SHORT CIRCUITED OUTPUT
The LM4132 features indefinite short circuit protection. This
protection limits the output current to 75mA when the output
is shorted to ground.
TURN ON TIME
Turn on time is defined as the time taken for the output
voltage to rise to 90% of the preset value. The turn on time
depends on the load. The turn on time is typically 33.2µs
when driving a 1µF load and 78.8µs when driving a 10µF
load. Some users may experience an extended turn on time
(up to 10ms) under brown out conditions and low tempera-
tures (-40˚C).
THERMAL HYSTERESIS
Thermal hysteresis is defined as the change in output volt-
age at 25oC after some deviation from 25oC. This is to say
that thermal hysteresis is the difference in output voltage
between two points in a given temperature profile. An illus-
trative temperature profile is shown in Figure 1.
This may be expressed analytically as the following:
Where
V
HYS
= Thermal hysteresis expressed in ppm
V
REF
= Nominal preset output voltage
V
REF1
=V
REF
before temperature fluctuation
V
REF2
=V
REF
after temperature fluctuation.
The LM4132 features a low thermal hysteresis of 75 ppm
(typical) from -40˚C to 125˚C after 8 temperature cycles.
TEMPERATURE COEFFICIENT
Temperature drift is defined as the maximum deviation in
output voltage over the operating temperature range. This
deviation over temperature may be illustrated as shown in
Figure 2.
Temperature coefficient may be expressed analytically as
the following:
20151338
FIGURE 1. Illustrative Temperature Profile
20151339
FIGURE 2. Illustrative V
REF
vs Temperature Profile
LM4132
www.national.com17
Application Information (Continued)
T
D
= Temperature drift
V
REF
= Nominal preset output voltage
V
REF_MIN
= Minimum output voltage over operating
temperature range
V
REF_MAX
= Maximum output voltage over operating
temperature range
∆T = Operating temperature range.
The LM4132 features a low temperature drift of 10ppm
(max) to 30ppm (max), depending on the grade.
LONG TERM STABILITY
Long-term stability refers to the fluctuation in output voltage
over a long period of time (1000 hours). The LM4132 fea-
tures a typical long-term stability of 50ppm over 1000 hours.
The measurements are made using 5 units of each voltage
option, at a nominal input voltage (5V), with no load, at room
temperature.
EXPRESSION OF ELECTRICAL CHARACTERISTICS
Electrical characteristics are typically expressed in mV, ppm,
or a percentage of the nominal value. Depending on the
application, one expression may be more useful than the
other. To convert one quantity to the other one may apply the
following:
ppm to mV error in output voltage:
Where:
V
REF
is in volts (V) and V
ERROR
is in milli-volts (mV).
Bit error (1 bit) to voltage error (mV):
V
REF
is in volts (V), V
ERROR
is in milli-volts (mV), and n is the
number of bits.
mV to ppm error in output voltage:
Where:
V
REF
is in volts (V) and V
ERROR
is in milli-volts (mV).
Voltage error (mV) to percentage error (percent):
Where:
V
REF
is in volts (V) and V
ERROR
is in milli-volts (mV).
PRINTED CIRCUIT BOARD and LAYOUT
CONSIDERATIONS
References in SOT packages are generally less prone to PC
board mounting than devices in Small Outline (SOIC) pack-
ages. To minimize the mechanical stress due to PC board
mounting that can cause the output voltage to shift from its
initial value, mount the reference on a low flex area of the PC
board, such as near the edge or a corner.
The part may be isolated mechanically by cutting a U shape
slot on the PCB for mounting the device. This approach also
provides some thermal isolation from the rest of the circuit.
Bypass capacitors must be mounted close to the part.
Mounting bypass capacitors close to the part will reduce the
parasitic trace components thereby improving performance.
LM4132
www.national.com 18
Typical Application Circuits
20151326
FIGURE 3. Voltage Reference with Complimentary Output
20151327
FIGURE 4. Precision Voltage Reference with Force and Sense Output
20151328
FIGURE 5. Programmable Current Source
LM4132
www.national.com19
Physical Dimensions inches (millimeters) unless otherwise noted
SOT23-5 Package
NS Package Number MF05A
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves
the right at any time without notice to change said circuitry and specifications.
For the most current product information visit us at www.national.com.
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS
WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body, or
(b) support or sustain life, and whose failure to perform when
properly used in accordance with instructions for use
provided in the labeling, can be reasonably expected to result
in a significant injury to the user.
2. A critical component is any component of a life support
device or system whose failure to perform can be reasonably
expected to cause the failure of the life support device or
system, or to affect its safety or effectiveness.
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National Semiconductor follows the provisions of the Product Stewardship Guide for Customers (CSP-9-111C2) and Banned Substances
and Materials of Interest Specification (CSP-9-111S2) for regulatory environmental compliance. Details may be found at:
www.national.com/quality/green.
Lead free products are RoHS compliant.
National Semiconductor
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Support Center
Email: new.feedback@nsc.com
Tel: 1-800-272-9959
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Email: europe.support@nsc.com
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www.national.com
LM4132 SOT-23 Precision Low Dropout Voltage Reference
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