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TL431 LINEAR INTEGRATED CIRCUIT
PROGRAMMABLE PRECISION
REFERENCE
DESCRIPTION
The Contek TL431 is a three-terminal adjustable regulator
with a guaranteed thermal stability over applicable
temperature ranges. The output voltage may be set to any
value between Vref(approximately 2.5V) and 36 V with two
external resistors. It provides very wide applications, including
shunt regulator, series regulator, switching regulator, voltage
reference and others.
FEATURES
*Programmable output Voltage to 36V.
*Low dynamic output impedance 0.2W
*Sink current capability of 1.0 to 100mA.
*Equivalent full-range temperature coefficient of 50ppm/ C
typical for operation over full rated operating temperature
range.
BLOCK DIAGRAM
Contek
REFERENCE
CATHODE
SOP-8
1
TO-92
1
SOT-89
SOP-8 1: Cathode 2,3,6,7: Anode 8:Ref.
4,5: N.C.
TO-92 1: Ref; 2:Anode; 3:Cathode
SOT-89 1: Ref; 2:Anode; 3:Cathode
CATHODE
(K)
REFERENCE
(R)
CONTEK
2.5V Vref
ANODE
Contek Microelectronics Co.,Ltd.
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ANODE(A)
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TL431 LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATINGS (Operating temperature range applies unless otherwise specified))
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
TO-92
SOP-8
SOT-89
Operating Junction Temperature Topr -20 ~ +85 C
Storage Temperature Temperature Tstg -65 ~ +150 C
RECOMMENDED OPERATING CONDITIONS
PARAMETER SYMBOL MIN TYP MAX UNIT
Cathode Voltage VKA VREF 36 V
Cathode Current IKA 10 mA
ELECTRICAL CHARACTERISTICS(Ta=25 C, unless otherwise specified)
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Reference Input Voltage Vref VKA=VREF,IKA=10mA 2.440 2.495 2.550 V
P
D 500
300
350
mW
mW
Deviation of reference Input Voltage
Over temperature(note 1)
Ratio of Change in Reference Input
Voltage to the Change in Cathode
Voltage
Reference Input Current Iref IKA=10mA,R1=10kW,R2= 1.5 4 mA
Deviation of Reference Input Current
Over Full Temperature Range
Minimum Cathode Current for
Regulation
Off-State Cathode Current IKA(OFF) VKA =36V,VREF=0 0.05 1.0 mA
Dynamic Impedance ZKA VKA=VREF,IKA=1 to 100mA
Note:TMIN=0 C,TMAX=+70 C
Remark: Reference voltage of =-1% tolerance is also available per customer s request.
DVref/DTVKA=VREF,IKA=10mA
MIN<=TA<=TMAX
T
V
KA=10V~VREF
DVref /DV
DIref/DTIKA=10mA,R1=10kW,R2=
IKA(min) VKA=VREF 0.45 1.0 mA
KA IKA=10mA
T
A=full Temperature
f1.0kHz
VKA=36V~10V
4.5 17 mV
-1.0 -2.7
-0.5
0.4 1.2 mA
0.15 0.5 W
mV/V
-2.0
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com
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TL431 LINEAR INTEGRATED CIRCUIT
TYPICAL PERFORMANCE CHARACTERISTICS
Fig 1 Cathode Current Vs Cathode Voltage
125
Ta=25 C
100
KA=VREF
V
75
50
25
0
-25
Cathode Current (mA)
-50
-75
-100
-2 -1 0 1 2 3
Fig 3 Change in Reference Input Voltage
0
-5
-10
-15
-20
-25
Voltage (mV)
-30
Change In Reference INput
-35
-40
0 5 10 15 20 25 30 35 40
2
10
Ta=25 C
I
KA =0mA to 100mA
)
1
10
Impedance (
0
10
-1
10
3
10
Cathode Voltage (V)
Vs Cathode voltage
Cathode Voltage (V)
Fig 5 Dynamic Impedance
Vs Frequency
4
5
1010
Frequency (Hz)
IKA =100mA
Ta=25
6
10
Fig 2 Cathode Current Vs Cathode Voltage
800
Ta=25 C
600
400
200
Cathode Current (mA)
0
-200
KA=VREF
V
IKA(min)
-2
-1 1023
Cathode Voltage (V)
Fig 4 Pulse Response
C
7
10
7
6
5
4
3
2
Input and Output Voltage (V)
1
0
Fig 6 Small Signal Voltage Amplification Vs Frequency
70
60
50
40
30
20
10
Voltage Amplification (dB)
0
-10
3
10
Ta=25 C
0 1234567
Time ( m s)
Ta=25 C
I
KA =10mA
4
5
1010
6
10
7
10
Frequency (Hz)
CONTEK
Contek Microelectronics Co.,Ltd.
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3
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TL431 LINEAR INTEGRATED CIRCUIT
TEST CIRCUIT
INPUT
VREF
IKA
VKA
ContekTL431
INPUT VKA
IKA
R1
IREF
VREF
R2
VKA=VREF*(1+R1/R2)+IREF* R1
Contek TL431
INPUT
VKA
IKA(OFF)
Contek TL431
Fig 7 Test Circuit For VKA =VREF Fig 8 Test Circuit for VKA >= VREF Fig 9 Test Circuit For IKA(OFF)
APPLICATION CIRCUIT
Vi Vo
R1
REF
V
R2
Contek
TL431
Vo=(1+R1/R2)*VREF
Vi
Contek7805
COMMON
Vo=(1+R1/R2)*V
IN
Contek
TL431
REF
OUT
Vo
R1
V
REF
R2
Vi
R1
REF
V
R2
Contek
TL431
Vo=(1+R1/R2)*VREF
Fig 10 Shutdown Regulator Fig 11 Output Control of a Three Fig 12 Higher-current Shunt Regulator
-Terminal Fixed Regulator
Vo
Contek TL431
Fig 13 Constant-current Sink Fig 14 Current Limiting or Current Source
CONTEK
Vi
Io
Vo
Vi
Io
Vo
RCL
Rs
Rs
IO=VREF/RS
Contek Microelectronics Co.,Ltd.
Contek TL431
S=VREF/RCL
R
4
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