Datasheet LM431SC, LM431SB, LM431SA Datasheet (Fairchild Semiconductor)

LM431SA/LM431SB/LM431SC

Programmable Shunt Regulator

www.fairchildsemi.com

Features

• Programmable Output Voltage to 36 Volts

• Low Dynamic Output Impedance 0.20 Typical

• Sink Curren t Capability of 1.0 to 100mA

• Equivalent Full-Range Temperature Coefficient of

50ppm/°C Typical

• Temperature Compensated for Operation Over Full Rated
Operating Temperature Range

• Low Output Noise Voltage

• Fast Turn-on Response

Description

The LM431SA/LM431SB/LM431SC are three terminal
output adjustable regulators with thermal stability over
operating temperature range. The output voltage can be set
any value between V
volts with two external resistors. These devices have a
typical dynamic output impedance of 0.2Ω Active output
circuit provides a sharp turn-on characteristic, making these
devices excellent replacement for Zener Diodes in many
applications.

SOT-89

1

1. Ref 2. Anode 3. Cathode

SOT-23F

3

2

1

1. Cathode 2. Ref 3. Anode

(approximat ely 2.5 volts) and 36

REF

Internal Block Diagram

©2002 Fairchild Semiconductor Corporation

Rev. 1.0.3

LM431SA/LM431SB/LM431SC

Absolute Maximum Ratings

(Operating temperature range applies unless otherwise specified.)

Parameter Symbol Value Unit

Cathode Voltage V
Cathode current Range (Continuous) I
Reference Input Current Range I
Thermal Resistance Junction-Air (Note1,2)

MF Suffix Package
ML Suffix Package

Power Dissipation (Note3,4)
MF Suffix Package
ML Suffix Package

Junction Temperature T
Operating Temperature Range T
Storage Temperature Range T

Note:

1. Thermal resistance test board

Size: 76.2mm * 114.3mm * 1.6mm (1S0P)
JEDEC Standard: JESD51-3, JESD51-7

2. Assume no ambient airflow.

3. T

JMAX

4. Power dissipation calculation: PD = (TJ - TA)/

= 150

°

, Ratings apply to ambient temperature at 25

C

R

θJA

REF

R

P

OPR
STG

°

C

KA

KA

θJA

D

J

37 V

-100 ~ +150 mA

0.05 ~ +10 mA

350

°C/W

220

350
560

150 °C

-25 ~ +85 °C

-65 ~ +150 °C

mW

Recommended Operating Conditions

Parameter Symbol Min. Typ. Max. Unit

Cathode Voltage V
Cathode Current I

KA

KA

V

REF

1.0 - 100 mA

-36V

2

Electrical Characteristics

(TA = +25°C, unless otherwise specified)

LM431SA/LM431SB/LM431SC

Parameter Symbol Conditions

Reference
Input Voltage

Deviation of
Reference
Input Voltage
Over­Temperature

Ratio of
Change in
Reference
Input Voltage

to the Change
in Cathode
Voltage

Reference
Input Current

Deviation of
Reference
Input Current
Over Full
Temperature
Range

Minimum
Cathode
Current for
Regulation

Off -Stage
Cathode
Current

Dynamic
Impedance

V

REF

V

∆

∆

V

∆

V

∆

I

REF

I

∆

REF

I

KA(MIN)VKA=VREF

I

KA(OFF)VKA

Z

REF

T

REF

KA

KA

/

/

/∆T

VKA=V

V

KA=VREF

T

MIN≤TA≤TMAX

IKA
=10mA

IKA=10mA,

=10KΩ,R2=∞

R

1

I

=10mA,

KA

=10KΩ,R2=∞

R

1

T

=Full Range

A

=36V, V

VKA=V
I

=1 to 100mA ,f ≥1.0kHz

KA

, IKA=10mA 2.450 2.500 2.550 2.470 2.495 2.520 2.482 2.495 2.508 V

REF

, IKA=10mA

∆

VKA=10V-

V

REF

VKA=36V-

∆

10V

=0 - 0.05 1.0 - 0.05 1.0 - 0.05 1.0

REF

,

REF

LM431SA LM431SB LM431SC

Min. Typ. Max. Min. Typ. Max. Min. Typ. Max.

-

4.5 17

- -1.0 -2.7 - -1.0 -2.7 - -1.0 -2.7

- -0.5 -2.0 - -0.5 -2.0 - -0.5 -2.0

-1.54 -1.54 -1.54

-

0.4 1.2

- 0.45 1.0 - 0.45 1.0 - 0.45 1.0 mA

- 0.15 0.5 - 0.15 0.5 - 0.15 0.5 Ω

-

-

4.5 17

0.4 1.2

-

4.5 17 mV

-

0.4 1.2

Unit

mV/V

A

µ

A

µ

A

µ

Note1

T

MIN

= -25°C, T

MAX

= +85°C

3

LM431SA/LM431SB/LM431SC

Test Circuits

LM431S

LM431S

Figure 1. Test Circuit for VKA=V

LM431S

Figure 3. Test Circuit for l

KA(OFF)

REF

Figure 2. Test Circuit for V

KA

≥≥≥≥V

REF

4

Typical Performance Characteristic s

LM431SA/LM431SB/LM431SC

150

VKA = V

REF

TA = 25oC

100

50

0

, Cathode Current (mA)

K

I

-50

-100

-2 -1 0 1 2 3

Figure 4.

Cathode Current vs. Cathode Voltage

0.100

0.075

0.050

0.025

, Off-State Cathode Current (uA)

off

I

0.000

-50 -25 0 25 50 75 100 125

VKA, Cathode Voltage (V)

TA, Ambient Temperature (oC)

800

VKA = V

REF

TA = 25oC

600

400

200

, CATHODE CURRENT (uA)

KA

I

0

-200

-10123

Figure 5.

Cathode Current vs. Cathode Voltage

3.5

3.0

2.5

2.0

1.5

1.0

, Reference Input Current (uA)

ref

I

0.5

0.0

-50-25 0 2550 75100125

VKA, CATHODE VOLTAGE (V)

I

KA(MIN)

TA, Ambient Temperature (oC)

Figure 6.

OFF-State Cathode Current vs.

Ambient Temperature

60

50

40

30

20

Open Loop Voltage Gain (dB)

10

0

-10
1k 10k 100k 1M 10M

Frequency (Hz)

TA = 25oC
IKA = 10mA

Figure 8. Small Signal Voltage Amplification vs. Frequency

Figure7. Reference Input Current vs.

Ambient Temper atu r e

6

TA=25oC

5

4

3

Voltage Swing (V)

2

1

0

048121620

Figure 9.

INPUT

OUTPUT

Time (us)

Pulse Response

5

LM431SA/LM431SB/LM431SC

Typical Performance Characte ristic s

140

120

100

80

60

40

, CATHODE CURRENT(mA)

K

I

20

0
100p 1n 10n 100n 1µ 10µ

A

Figure 10. Stability Boundary Conditions

5

4

3

2

Current(mA)

B

CL, LOAD CAPACITANCE

A VKA = Vref

= 5.0 V @ IK = 10

B V

KA

TA = 25oC

mA

(Continued)

5

4

3

2

Current(mA)

1

0

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Anode-Ref. Voltage(V)

Figure 11. Anode-Reference Diode Curve

1

0

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Ref.-Cathode Voltage(V)

Figure 12. Reference-Cathode Diode Curve

6

Typical Application

LM431SA/LM431SB/LM431SC

R

1



V

1

------ -+

=

O



Figure 13. Shunt Regulator

V

R

2

LM431S

ref

-

LM431S

Figure 16. Curr ent Limit or Cur rent Source

R

1

VOV

LM7805/MC7805

Figure 14



1

=

LM431S

.

Output Control for

------ -+

ref



R

2

Three-Termianl Fixed Regulator

R



V

1

------ -+

=

O



R

Figure 15. High Current Shunt Re gulator

LM431S

Figure 17. Constant-Current Sink

1

V

ref

2

LM431S

7

LM431SA/LM431SB/LM431SC

Mechanical Dimensions

Package

Dimensions in millimeters

SOT-23F

Marking

8

43A

43B

43C

2% tolerance 1% tolerance 0.5% tolerance

LM431SA/LM431SB/LM431SC

Mechanical Dimensions

Package

4.50

±0.20

1.65

±0.10

(Continued)

SOT-89

C0.2

(0.50)

±0.20

2.50

(1.10)

±0.20

4.10

Dimensions in millimeters

1.50

±0.20

(0.40)

0.50

Marking

±0.10

1.50 TYP 1.50 TYP

43A

0.40

±0.10

0.40

+0.10
–0.05

43B 43C

2% tolerance

1% tolerance

0.5% tolerance

9

LM431SA/LM431SB/LM431SC

Ordering Information

Product Number Output Voltage Tolerance Package Operating Temperature

LM431SCCML
LM431SCCMF SOT-23F
LM431SBCML
LM431SBCMF SOT-23F
LM431SACML
LM431SACMF SOT-23F

0.5%

1%

2%

SOT-89

SOT-89

SOT-89

-25 ~ +85°C

DISCLAIMER

FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURT HER NOTICE TO ANY
PRODUCTS HEREI N TO IMPROVE RELIABILITY, FUNCTIO N OR DESIGN. FAIRCH IL D DOES NOT ASSUME ANY
LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER
DOES IT CONVEY ANY LICENSE UNDER IT S PATENT RIGHTS, NOR THE RIGHTS OF OTHE RS.

LIFE SUPPORT POL I CY

FAIRCHILD’S PR ODUCTS ARE NOT AUTH ORIZED FOR USE AS C RITICAL COMPONENT S IN LIFE SUPPORT DE VICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD 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 (c) 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 of the
user.

www.fairchildsemi.com

2. A critical component in any component of a life support
device or sy stem whose fai lure to perform can be
reasonably expec ted to cause the failur e of the life support
device or system, or to affect its safety or effec t iv ene ss .

11/14/02 0.0m 001

 2002 Fairchild Semiconductor Corporation

Stock#DSxxxxxxxx