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LMV431/LMV431A/LMV431B Low-Voltage (1.24V) Adjustable Precision Shunt Regulators
May 2005
LMV431/LMV431A/LMV431B
Low-Voltage (1.24V) Adjustable Precision Shunt
Regulators
General Description
The LMV431, LMV431A and LMV431B are precision 1.24V
shunt regulators capable of adjustment to 30V. Negative
feedback from the cathode to the adjust pin controls the
cathode voltage, much like a non-inverting op amp configu-
ration (Refer to Symbol and Functional diagrams). A two
resistor voltage divider terminated at the adjust pin controls
the gain of a 1.24V band-gap reference. Shorting the cath-
ode to the adjust pin (voltage follower) provides a cathode
voltage of a 1.24V.
The LMV431, LMV431A and LMV431B have respective ini-
tial tolerances of 1.5%, 1% and 0.5%, and functionally lends
themselves to several applications that require zener diode
type performance at low voltages. Applications include a 3V
to 2.7V low drop-out regulator, an error amplifier in a 3V
off-line switching regulator and even as a voltage detector.
These parts are typically stable with capacitive loads greater
than 10nF and less than 50pF.
The LMV431, LMV431A and LMV431B provide performance
at a competitive price.
Features
n
Low Voltage Operation/Wide Adjust Range (1.24V/30V)
n
0.5% Initial Tolerance (LMV431B)
n
Temperature Compensated for Industrial Temperature
Range (39 PPM/˚C for the LMV431AI)
n
Low Operation Current (55µA)
n
Low Output Impedance (0.25Ω)
n
Fast Turn-On Response
n
Low Cost
Applications
n
n
n
n
n
n
n
Shunt Regulator
Series Regulator
Current Source or Sink
Voltage Monitor
Error Amplifier
3V Off-Line Switching Regulator
Low Dropout N-Channel Series Regulator
Connection Diagrams
TO92: Plastic Package
SOT23-3
10095801
Top View
10095867
SOT23-5
Top View
10095844
*
Pin 1 is not internally connected.
*
Pin 2 is internally connected to Anode pin. Pin 2 should be either floating
or connected to Anode pin.
Top View
© 2005 National Semiconductor Corporation
DS100958
www.national.com
LMV431/LMV431A/LMV431B
Symbol and Functional Diagrams
10095859
10095860
Simplified Schematic
10095803
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2
LMV431/LMV431A/LMV431B
Ordering Information
Package
Temperature
Range
Industrial Range
−40˚C to +85˚C
TO92
Commerial Range
0˚C to +70˚C
Voltage Tolerance
1%
1.5%
0.5%
1%
1.5%
1%
Industrial Range
−40˚C to +85˚C
1%
1.5%
1.5%
SOT23-5
Commercial Range
0˚C to +70˚C
0.5%
0.5%
1%
1%
1.5%
1.5%
0.5%
SOT23-3
Industrial Range
−40˚ to +85˚C
0.5%
1%
1%
Part Number
LMV431AIZ
LMV431IZ
LMV431BCZ
LMV431ACZ
LMV431CZ
LMV431AIM5
LMV431AIM5X
LMV431IM5
LMV431IM5X
LMV431BCM5
LMV431BCM5X
LMV431ACM5
LMV431ACM5X
LMV431CM5
LMV431CM5X
LMV431BIMF
LMV431BIMFX
LMV431AIMF
LMV431AIMFX
Package Marking
LMV431AIZ
LMV431IZ
LMV431BCZ
LMV431ACZ
LMV431CZ
N08A
N08A
N08B
N08B
N09C
N09C
N09A
N09A
N09B
N09B
RLB
MF03A
RLA
MF05A
Z03A
NSC Drawing
DC/AC Test Circuits for Table and
Curves
10095805
Note:
V
Z
= V
REF
(1 + R1/R2) + I
REF
•
R1
10095804
FIGURE 2. Test Circuit for V
Z
>
V
REF
FIGURE 1. Test Circuit for V
Z
= V
REF
10095806
FIGURE 3. Test Circuit for Off-State Current
3
www.national.com
LMV431/LMV431A/LMV431B
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Storage Temperature Range
Operating Temperature Range
Industrial (LMV431AI, LMV431I)
Commercial (LMV431AC,
LMV431C, LMV431BC)
Lead Temperature
TO92 Package/SOT23 -5,-3 Package
(Soldering, 10 sec.)
Internal Power Dissipation (Note 2)
TO92
SOT23-5, -3 Package
Cathode Voltage
Continuous Cathode Current
Reference Input Current range
265˚C
0.78W
0.28W
35V
−30 mA to +30mA
−.05mA to 3mA
−40˚C to +85˚C
0˚C to +70˚C
−65˚C to +150˚C
Cathode Current
Temperature range
LMV431AI
Thermal Resistance (θ
JA
)(Note 3)
SOT23-5, -3 Package
TO-92 Package
Derating Curve (Slope = −1/θ
JA
)
0.1 mA to 15mA
−40˚C
≤
T
A
≤
85˚C
455 ˚C/W
161 ˚C/W
10095830
Operating Conditions
Cathode Voltage
V
REF
to 30V
LMV431C Electrical Characteristics
T
A
= 25˚C unless otherwise specified
Symbol
V
REF
V
DEV
Parameter
Reference Voltage
Deviation of Reference Input Voltage
Over Temperature (Note 4)
Ratio of the Change in Reference
Voltage to the Change in Cathode
Voltage
I
REF
∝
I
REF
I
Z(MIN)
I
Z(OFF)
r
Z
Reference Input Current
Deviation of Reference Input Current
over Temperature
Minimum Cathode Current for
Regulation
Off-State Current
Dynamic Output Impedance (Note 5)
Conditions
V
Z
= V
REF
, I
Z
= 10mA
(See Figure 1
)
T
A
= 25˚C
T
A
= Full Range
Min
1.222
1.21
4
−1.5
Typ
1.24
Max
1.258
1.27
12
−2.7
V
mV
mV/V
Units
V
Z
= V
REF
, I
Z
= 10mA,
T
A
= Full Range
(See Figure 1)
I
Z
= 10mA
(see Figure 2
)
V
Z
from V
REF
to 6V
R
1
= 10k, R
2
=
∞
and 2.6k
R
1
= 10kΩ, R
2
=
∞
I
I
= 10mA
(see Figure 2)
R
1
= 10kΩ, R
2
=
∞
,
I
I
= 10mA, T
A
= Full Range
(see Figure 2)
V
Z
= V
REF
(see Figure 1)
V
Z
=6V, V
REF
= 0V
(see Figure 3
)
V
Z
= V
REF
, I
Z
= 0.1mA to 15mA
Frequency = 0Hz
(see Figure 1)
0.15
0.5
µA
0.05
55
0.001
0.25
0.3
80
0.1
0.4
µA
µA
µA
Ω
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