©2001 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev. 1.0.4
Features
• Programmable outpu t volt age to 36 vol ts
• Low dynamic output impedance 0.20 typical
• Sink current capability of 1.0 to 100mA
• Equivalent full-range temp erature coefficient of 50ppm/
°C typical
• Temperature compensated for operation over full rated
operating temp erature range
• Low outpu t noise voltage
• Fast turn-on response
Description
The LM431A/LM431B/LM431C are three terminal output
adjustable regulators with thermal stability over operating
temperature range. The output voltage can be set any value
between VREF (approximately 2.5 volts) and 36 volts with
two external resistors. These devices have a typical dynam ic
output impedance of 0.2Ω Active output circuit provides a
sharp turn-on characteristic, making these devices excellent
replacement for Zener Diodes in many applicatio ns.
TO-92
8-DIP 8-SOP
1. Ref 2. Anode 3. Cathode
1
11
SOT-23F
12
3
1. Cathode 2. Ref 3. Anode
1. Ref 2. Anode 3. Cathode
1.Catho de 2.3.6.7.Anode
4.5.NC 8.Ref
1
SOT-89
1.Cat hode 2. 3.4. 5.7. NC
6.Anode 8.Ref
Internal Block Diagram
LM431A/LM431B/LM431C
Programmable Shunt Regulator
LM431A/LM431B/LM431C
2
Absolute Maximum Ratings
(Operating temperature range applies unless otherwise specified.)
Recommended Operating Conditions
Parameter Symbol Value Unit
Cathode Voltage VKA 37 V
Cathode current Range (Continuous) IKA -100~ + 150 mA
Reference Input Current Range IREF 0.05~ + 10 mA
Power Dissipation
M, Z Suffix Package PD770 mW
Operating Temperature Range
LM431xC TOPR -25 ~ + 85 oC
LM431xI -40 ~ + 85 oC
Storage Temperature Range TSTG -65 ~ + 150 oC
Parameter Symbol Min Typ Max Unit
Cathode Voltage VKA VREF -36V
Cathode Current IKA 1.0 - 100 mA
LM431A/LM431B/LM431C
3
Electrical Characteristics
(TA = +25°C, unless otherwise specified)
Note1
• LM431XC : TMIN= -25 °C, TMAX= +85 °C
• LM431XI : TMIN= -40 °C, TMAX= +85 °C
Parameter Symbol Conditions LM431A LM431B LM431C Unit
Min. Typ. Max. Min. Typ. Max. Min. Typ. Max.
Reference
Input Voltage VREF VKA=VREF, IKA=10mA 2.450 2.500 2.550 2.470 2.495 2.520 2.482 2.495 2.508 V
Deviation of
Reference
Input Voltage
Over-
Temperature
∆
VREF/
∆
TVKA=VREF, IKA=10mA
TMIN≤TA≤TMAX -4.5 17 -4.5 17 -4.5 17 mV
Ratio of
Change in
Reference
Input Voltage
∆
VREF/
∆
VKA IKA
=10mA
∆
VKA=10V-
VREF - - 10 - 2.7 - - 1.0 - 2.7 - - 1.0 - 2.7
mV/V
to the Change
in
Cathode
Voltage
∆
VKA=36V-
10V - -0.5 -2.0 - -0.5 -2.0 - -0.5 -2.0
Reference
Input Current IREF IKA=10mA,
R1=10KΩ,R2=∞-1.54 -1.54 -1.54
µ
A
Deviation of
Reference
Input Current
Over Full
Temperature
Range
∆
IREF/
∆
T
IKA=10mA,
R1=10KΩ,R2=∞
TA =Full Range -0.4 1.2 -0.4 1.2 -0.4 1.2
µ
A
Minimum
Cathode Cur-
rent for
Regulation
IKA(MIN) VKA=VREF - 0.45 1.0 - 0.45 1.0 - 0.45 1.0 mA
Off - Stage
Cathode
Current IKA(OFF) VKA=36V,
VREF=0 - 0.05 1.0 - 0.05 1.0 - 0.05 1.0
µ
A
Dynamic
Impedance ZKA VKA=VREF,
IKA=1 to 100mA
f ≥1.0KHz - 0.15 0.5 - 0.15 0.5 - 0.15 0.5 Ω
LM431A/LM431B/LM431C
4
Test Circuits
Figure 1. Test Circ uit fo r VKA=VREF Figure 2. Test Circuit for VKA≥
≥≥
≥VREF
LM431A/B/C
LM431A/B/C
LM431A/B/C
Figure 3. Test Circuit for lKA(OFF)
LM431A/LM431B/LM431C
5
Typical Perfomance Characteristics
Figure 1. Cathode Current vs. Cathode Voltage
Figure 3. Change In Reference Input Voltage vs.
Cathode Vol tage
Figure 5. Small Signal Voltage Amplification vs. Frequency
Figu re 2. Ca tho d e Cur r en t vs. Ca th ode Voltag e
Figure 4. Dynamic Impedance Frequency
Figure 6. Pulse Response
LM431A/LM431B/LM431C
6
Typical Application
Figure 10. Shunt Regulator Figure 11. Output Control for Three-
Termianl Fixed Regulator Figure 12. High Current Sh unt R egula-
tor
Figure 13 . Current Limit or Curr ent Source Figure 14. Constant-Current Sink
VO1R1
R2
-------+


Vref
=
LM431A/B/C
VOVref 1R1
R2
-------+


=
LM431A/B/C
LM7805/MC7805
VO1R1
R2
-------+


Vref
=
LM431A/B/C
LM431A/B/C LM431A/B/C
LM431A/LM431B/LM431C
7
Mechanical Dimensions
Package
0.46
±0.10
1.27TYP
(R2.29)
3.86MAX
[1.27
±0.20
]1.27TYP
[1.27
±0.20
]
3.60
±0.20
14.47
±0.40
1.02
±0.10
(0.25) 4.58
±0.20
4.58
+0.25
–0.15
0.38
+0.10
–0.05
0.38
+0.10
–0.05
TO-92
LM431A/LM431B/LM431C
8
Mechanical Dimensions (Continued)
Package
4.92
±0.20
0.194
±0.008
0.41
±0.10
0.016
±0.004
1.27
0.050
5.72
0.225
1.55
±0.20
0.061
±0.008
0.1~0.25
0.004~0.001
6.00
±0.30
0.236
±0.012
3.95
±0.20
0.156
±0.008
0.50
±0.20
0.020
±0.008
5.13
0.202 MAX
#1
#4 #5
0~8°
#8
0.56
0.022
()
1.80
0.071
MAX0.10
MAX0.004
MAX
MIN
+0.10
-0.05
0.15+0.004
-0.002
0.006
8-SOP
LM431A/LM431B/LM431C
9
Mechanical Dimensions (Continued)
Package
8-DIP
6.40 ±0.20
3.30 ±0.30
0.130 ±0.012
3.40 ±0.20
0.134 ±0.008
#1
#4 #5
#8
0.252 ±0.008
9.20 ±0.20
0.79
2.54
0.100
0.031
()
0.46 ±0.10
0.018 ±0.004
0.060 ±0.004
1.524 ±0.10
0.362 ±0.008
9.60
0.378 MAX
5.08
0.200
0.33
0.013
7.62
0~15°
0.300
MAX
MIN
0.25 +0.10
–0.05
0.010+0.004
–0.002
LM431A/LM431B/LM431C
10
Mechanical Dimensions (Continued)
Package
SOT-23F
0.96~1.14
0.12
0.03~0.10
0.38 REF
0.40 ±0.03
2.90 ±0.10
0.95 ±0.03 0.95 ±0.03
1.90 ±0.03 0.508REF
0.97REF 1.30 ±0.10 0.45~0.60
2.40 ±0.10
+0.05
–0.023
0.20 MIN
0.40 ±0.03
LM431A/LM431B/LM431C
11
Mechanical Dimensions (Continued)
Package
SOT-89
0.40
±0.10
2.50
±0.20
(0.50)
(0.40)
4.10
±0.20
0.40
+0.10
–0.05
0.50
±0.10
1.65
±0.10
4.50
±0.20
1.50
±0.20
C0.2
1.50 TYP 1.50 TYP
(1.10)
LM431A/LM431B/LM431C
6/29/01 0.0m 001
Stock#DSxxxxxxxx
2001 Fairchild Semicond uctor Corporation
LIFE SU PP ORT POL ICY
FAIRCHILD’S PRODUCTS AR E NOT AUTHORIZED FOR USE AS C RITICAL COMPONENTS I N LIFE S UPPORT DEVICE S
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
CORPORA TION. As used he rein :
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.
2. A critical component in any component of a life support
device or syst em who se failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effec tiv ene ss.
www.fairchildsemi.com
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY
PRO DUCTS HEREIN TO IMPROVE RELIABILITY, FUN C TION OR DESIGN . FAIRCHILD DO ES 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 ITS PATENT RIG HTS, NOR THE RIGHTS OF OTHERS.
Ordering Information
Product Number Output Voltage Tolerance Package Operating Temp erature
LM431CCZ
0.5%
TO-92
-25 ~ + 85 oC
LM431CCM 8-SOP
LM431CCML SOT-89
LM431CCMF SOT-23F
LM431BCZ
1%
TO-92
LM431BCM 8-SOP
LM431BCML SOT-89
LM431BCMF SOT-23F
LM431ACN
2%
8-DIP
LM431ACZ TO-92
LM431ACM 8-SOP
LM431ACML SOT-89
LM431ACMF SOT-23F
LM431CIZ 0.5% TO-92
-40 ~ + 85 oC
LM431CIM 8-SOP
LM431BIZ 1% TO-92
LM431BIM 8-SOP
LM431AIZ 2% TO-92
LM431AIM 8-SOP