Datasheet LM431CIZ, LM431CIMX, LM431CIM3X, LM431CIM3, LM431BIM3 Datasheet (NSC)

LM431
Adjustable Precision Zener Shunt Regulator

LM431 Adjustable Precision Zener Shunt Regulator

December 1999

General Description

The LM431 is a 3-terminal adjustable shunt regulator with
guaranteed temperature stability over the entire temperature
range of operation. It is now available in a chip sized pack­age (4-Bump micro SMD) using National’s micro SMD pack­age technology. The output voltage may be set at any level
greater than 2.5V (V
external resistors that act as a voltage divided network. Due
to the sharp turn-on characteristics this device is an excel­lent replacement for many zener diode applications.

) up to 36V merely by selecting two

REF

Connection Diagrams

TO-92: Plastic Package

DS010055-1

Top View

SO-8: 8-Pin Surface Mount

Features

n Average temperature coefficient 50 ppm/˚C
n Temperature compensated for operation over the full

temperature range

n Programmable output voltage
n Fast turn-on response
n Low output noise
n LM431 in micro SMD package

SOT-23: 3-Lead Small Outline

DS010055-28

Top View

4-Bump micro SMD

DS010055-54

DS010055-2

Top view

© 1999 National Semiconductor Corporation DS010055 www.national.com

Top View

(bump side down)

Ordering Information

LM431

Package Typical Accuracy Order Number/Package Marking Temperature

%

0.5

TO-92 LM431CCZ/

SO-8 LM431CCM/

SOT-23 LM431CCM3/

micro SMD

Note 1: The micro SMD package marking is a 2 digit manufacturing Date Code only

LM431CCZ
LM431CIZ/

LM431CIZ

431CCM
LM431CIM/

431CIM

N1B
LM431CIM3

N1A

––

%

1

LM431BCZ/
LM431BCZ

LM431BIZ/
LM431BIZ

LM431BCM/
431BCM

LM431BIM/
431BIM

LM431BCM3/
N1D

LM431BIM3
N1C

%

2

LM431ACZ/
LM431ACZ

LM431AIZ/
LM431AIZ

LM431ACM/
LM431ACM

LM431AIM/
LM431AIM

LM431ACM3/
N1F

LM431AIM3
N1E

LM431AIBP
LM431AIBPX(Note 1)

micro SMD Top View Marking Example

Range

0˚C to +70˚C

−40˚C to +85˚C

0˚C to +70˚C

−40˚C to +85˚C

0˚C to +70˚C

−40˚C to +85˚C

−40˚C to +85˚C

Transport Media NSC

Rails Z03A

Rails and Tape &Reel M08A

Rails and Tape &Reel MA03B

250 Units Tape and Reel

3k Units Tape and Reel

Drawing

BPA04AFA

DS010055-56

The LM431 micro SMD Package will be marked with a two digit date manufacturing code. The underline indicates the bottom of
the marking. Pin one will be placed at the bottom left hand corner,and the rest of the pin numbers will follow counter-clockwise.

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Symbol and Functional Diagrams

DS010055-99

DC Test Circuits

LM431

DS010055-55

DS010055-4

FIGURE 1. Test Circuit for V

=

=

V

Z

REF

Note: V

Z

V

REF

(1 + R1/R2) + I

FIGURE 2. Test Circuit for V

DS010055-6

FIGURE 3. Test Circuit for Off-State Current

REF

•

R1

DS010055-5

>

V

Z

REF

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Absolute Maximum Ratings (Note 2)

LM431

If Military/Aerospace specified devices are required,
please contact the NationalSemiconductorSalesOffice/
Distributors for availability and specifications.

Storage Temperature Range −65˚C to +150˚C
Operating Temperature Range

Reference Voltage −0.5V
Reference Input Current 10 mA
Internal Power Dissipation (Notes 3, 4)

TO-92 Package
SO-8 Package
SOT-23 Package

micro SMD Package 0.30W
Industrial (LM431xI) −40˚C to +85˚C
Commercial (LM431xC) 0˚C to +70˚C

Soldering Information

Infrared or Convection (20 sec.) 235˚C
Wave Soldering (10 sec.) 260˚C (lead temp.)

Cathode Voltage 37V

Operating Conditions

Cathode Voltage V
Cathode Current 1.0 mA 100 mA

Min Max

REF

Continuous Cathode Current −10 mA to +150 mA

LM431
Electrical Characteristics

=

T

25˚C unless otherwise specified

A

Symbol Parameter Conditions Min Typ Max Units

V

REF

Reference Voltage V

=

Z

LM431A

=

V

Z

LM431B

=

V

Z

LM431C

V

DEV

I

REF

∝

I

I

Z(MIN)

I

Z(OFF)

r

Z

REF

Deviation of Reference Input Voltage Over V
Temperature (Note 5) T

Ratio of the Change in Reference Voltage I
to the Change in Cathode Voltage
Reference Input Current R

Deviation of Reference Input Current over R
Temperature I

Minimum Cathode Current for Regulation V
Off-State Current V
Dynamic Output Impedance (Note 6) V

=

Z

=

A

=

Z

(Figure 2 )

=

1

=

I

10 mA

I

=

1

=

10 mA, 0.4 1.2 µA

I

=

T

A

=

Z

=

Z

=

Z

Frequency=0Hz

=

V

Z

Frequency=0Hz

Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when operating the device
beyond its rated operating conditions.

Note 3: T
Note 4: Ratings apply to ambient temperature at 25˚C. Above this temperature, derate the TO-92 at 6.2 mW/˚C, the SO-8 at 6.5 mW/˚C, the SOT-23 at 2.2 mW/˚C

and the micro SMD at 3mW/˚C.
Note 5: Deviation of reference input voltage, V

J Max

=

150˚C.

, is defined as the maximum variation of the reference input voltage over the full temperature range.

DEV

=

V

10 mA 2.440 2.495 2.550 V

REF,II

(Figure 1 )

=

V

10 mA 2.470 2.495 2.520 V

REF,II

(Figure 1 )

=

V

10 mA 2.485 2.500 2.510 V

REF,II

(Figure 1 )

=

V
Full Range

10 mA V

10 mA, 8.0 17 mV

REF,II

(Figure 1 )

from V

Z

to 10V −1.4 −2.7

REF

VZfrom 10V to 36V −1.0 −2.0

=

∞

10 kΩ,R

, 2.0 4.0 µA

2

(Figure 2 )

=

∞

2

(Figure 2 )

(Figure 1 )

=

0V

REF

,

(Figure 3 )

0.4 1.0 mA

0.3 1.0 µA

10 kΩ,R

Full Range
V

REF

36V, V

, LM431A, 0.75 Ω

V

REF

(Figure 1 )

, LM431B, LM431C 0.50 Ω

V

REF

(Figure 1 )

37V

0.78W

0.81W

0.28W

mV/V

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LM431
Electrical Characteristics

LM431

(Continued)

The average temperature coefficient of the reference input voltage,∝V

Where:

=

T

full temperature change (0-70˚C).

2−T1

∝

can be positive or negative depending on whether the slope is positive or negative.

V

REF

Example: V

Note 6: The dynamic output impedance, rZ, is defined as:

When the device is programmed with two external resistors, R1 and R2, (see

DEV

=

8.0 mV, V

REF

=

2495 mV, T

=

70˚C, slope is positive.

2−T1

REF

Equivalent Circuit

, is defined as:

Figure 2

DS010055-7

), the dynamic output impedance of the overall circuit, rZ, is defined as:

DS010055-3

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Typical Performance Characteristics

LM431

Input Current vs V

Z

Thermal Information

Input Current vs V

Z

DS010055-29

Dynamic Impedance vs Frequency

Stability Boundary Conditions

DS010055-9

DS010055-30

DS010055-31

DS010055-10

Note: The areas under the curves represent conditions that may cause the device to oscillate. For curves B, C, and D, R2 and V+were adjusted to establish
the initial V

and IZconditions with C

Z

Test Circuit for Curve A Above

+

=

and CLwere then adjusted to determine the ranges of stability.

0. V

L

Test Circuit for Curves B, C and D Above

DS010055-12

DS010055-11

DS010055-13

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Typical Applications

LM431

Shunt Regulator

Series Regulator

DS010055-14

DS010055-16

Single Supply Comparator with

Temperature Compensated Threshold

DS010055-15

Output Control of a Three

Terminal Fixed Regulator

DS010055-17

Higher Current Shunt Regulator

DS010055-18

Crow Bar

DS010055-19

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Typical Applications (Continued)

LM431

Over Voltage/Under Voltage

Protection Circuit

DS010055-20

Voltage Monitor

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DS010055-21

Typical Applications (Continued)

LM431

Delay Timer

Current Limiter or Current Source

DS010055-23

DS010055-22

Constant Current Sink

Application Info

1.0 Mounting

To ensure that the geometry of the micro SMD package
maintains good physical contact with the printed circuit
board, pin 1 (NC) must be soldered to the pcb. Please see
AN-1112 for more detailed information regarding board
mounting techniques for the micro SMD package.

DS010055-24

2.0 LM431 micro SMD Light Sensitivity

When the LM431 micro SMD package is exposed to bright
sunlight, normal office fluorescent light, and other LED’s and
lasers, it operates within the guaranteed limits specified in
the electrical characteristics table.

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Physical Dimensions inches (millimeters) unless otherwise noted

LM431

NS Package Number M08A

SOT-23 Molded Small Outline Transistor Package (M3)

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NS Package Number MA03B

Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

NS Package Number Z03A

LM431

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

LM431

NOTES: UNLESS OTHERWISE SPECIFIED

1. EPOXY COATING

2. 63Sn/37Pb EUTECTIC BUMP

3. RECOMMEND NON-SOLDER MASK DEFINED LANDING PAD.

4. PIN 1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION. REMAINING PINS ARE
NUMBERED.

5. XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH, X2 IS PACK­AGE LENGTH AND X3 IS PACKAGE HEIGHT.

6. REFERENCE JEDEC REGISTRATION MO-211, VARIATION BA.

4-Bump micro SMD

X1=0.780 X2=0.900 X3=0.700

NS Package Number BPA04AFA

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Notes

LM431 Adjustable Precision Zener Shunt Regulator

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

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.

labeling, can be reasonably expected to result in a
significant injury to the user.

National Semiconductor
Corporation

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Tel: [phone]
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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.

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