©2002 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev. 1.0.6
Features
• Programmable Output Voltage to 36 Volts
• Low Dynamic Output Impedance 0.20 Typical
• Sink Curr ent Capabil ity of 1.0 t o 100mA
• Equivalent Full-Range Temperature Coefficient of
50ppm/°C Typical
• Temperature Compensated for Operation Over Full Rated
Operating Temperatur e Ra nge
• Low Output 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
1.Catho de 2.3.6.7.A node
4.5.NC 8.Ref
1.Cat hode 2. 3.4. 5.7. NC
6.Anode 8.Ref
Internal Block Diagram
CATHODE
ANODE
REFERENCE
CATHO D E ( K)
ANODE (A)
REFERENCE (R)
2.5 Vref
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
N Suffix Package PD770
1000 mW
Operating Temperature Range
LM431xC TOPR -25 ~ +85 °C
LM431xI -40 ~ +85 °C
Junction Temperature TJ150 °C
Storage Temperature Range TSTG -65 ~ +150 °C
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
•LM431
XC : TMIN = -25 °C, TMAX = +85°C
•LM431
XI : 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
to the Change
in Cathode
Voltage
∆
VREF/
∆
VKA IKA
=10mA
∆
VKA=10V-
VREF - -1.0 -2.7 - -1.0 -2.7 - -1.0 -2.7
mV/V
∆
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 Performance Cha racteristics
Figure 4. Cathode Current vs. Cathode Voltage Figure 5. Cathode Current vs. Cathode Voltage
Figure 6. Change In Reference Input Voltage vs.
Cathode Voltage Figure7. Dynamic Impedance Frequency
Figure 8. Small Signal Voltage Amplification vs. Frequency Figure 9. Pulse Re sp onse
LM431A/LM431B/LM431C
6
Typica l Perfo rmance Characteristics (Continued)
100p 1n 10n 100n 1µ 10µ
0
20
40
60
80
100
120
140
D
C
B
A
A VKA = Vref
B VKA = 5.0 V @ IK = 10mA
C VKA = 10 V @ IK = 10mA
D VKA = 15 V @ IK = 10mA
TA = 25oC
IK, CATHODE CURRE NT(mA)
CL, LOAD CAPACITANCE
Figure 10. Stability Boundary Conditions
LM431A/LM431B/LM431C
7
Typical Application
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
Figure 11. Shunt Regulator Figure 12. Output Control for
mi nal Fixed RegulatorThree- Ter--Figure 13. High Current Shunt Regulator
Figure 14. Current Limit or Current Source Figure 15. Constant-C urre nt Sink
LM431A/LM431B/LM431C
8
Mechanical Dimensions
Package Dimensions in millimeters
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
9
Mechanical Dimensions (Continued)
Package Dimensions in millimeters
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
10
Mechanical Dimensions (Continued)
Package Dimensions in millimeters
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
11
Ordering Information
Product Number Output Voltage Tolerance Package Operating Temp erature
LM431CCZ 0.5% TO-92
-25 ~ +85°C
LM431CCM 8-SOP
LM431BCZ 1% TO-92
LM431BCM 8-SOP
LM431ACN 2% 8-DIP
LM431ACZ TO-92
LM431ACM 8-SOP
LM431CIZ 0.5% TO-92
-40 ~ +85°C
LM431CIM 8-SOP
LM431BIZ 1% TO-92
LM431BIM 8-SOP
LM431AIZ 2% TO-92
LM431AIM 8-SOP
LM431A/LM431B/LM431C
8/20/02 0.0m 001
Stock#DSxxxxxxxx
2002 Fairchild Semicond uctor Corporation
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