UMW
R
UMW TL431
Adjustable Precision Shunt Regulator
Description
The TL431 is a three-terminal
adjustable regulator series with a
guaranteed thermal stability over
applicable temperature ranges. The
output voltage may be set to any
value between Vref and 36 volts with
two external resistors. These device
have a typical dynamic output
impedance of 0.27Ω, Active output
circuitry provides a very sharp
turn-on characteristic, making these
devices excellent replacement for
zener diodes in many applications.
Features
Programmable Output Voltage to 36V.
Low Dynamic Output Impedance :
TL431xxC/I: 0.27
Ω
(Typical).
TL431xxQ: 0.15
Ω
(Typical)
Sink Current Capability of 0.1mA to
100mA.
Equivalent Full-Range Temperature
Coefficient of 50 ppm/
o
C
Temperature Compensated for
Operation over Full Rated Operating
Temperature Range.
Low Output Noise Voltage.
Fast Turn on Responds.
SOT-23, TO-92, SOT-89, SOP-8
packages
Symbol
Applications
Precision Voltage Reference
Linear Regulator
Adjustable Power Supply
Switching Power Supply
Graphic Card
Adapter
Pin Description
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UMW
R
UMW TL431
Absolute Maximum Ratings
Symbol
V
KA
I
K
I
REF
T
oper.
T
J
T
stg
Cathode Voltage
Parameter
TL431xxC/I
TL431xxQ
Value
40
42
-100~150
0.05~10
TL431xxC
Operating Temperature Range
Junction Temperature Range
Storage Temperature Range
TL431xxI
TL431xxQ
0~+70
-40~+125
-60~+125
150
-65~+150
o
o
o
Unit
V
mA
mA
C
C
C
Cathode Current Range(Continuous)
Reference Input Current Range
Thermal Characteristics
Symbol
Parameter
Thermal Resistance From Junction to
Ambient in Free Air. (Measured with the
component mounted on a high effective
thermal conductivity test board in free air.)
Package
SOT-23
TO-92
SOT-89
SOP-8
Typical Value
416
250
250
210
o
Unit
θ
JA
C/W
Recommended Operating Conditions
Symbol
V
KA
I
K
Characteristic
Cathode Voltage
Cathode Current
TL431xxC/I
TL431xxQ
TL431xxC/Q
TL431xxI
Min.
V
REF
V
REF
0.5
1
-
-
Typ.
-
Max.
36
40
100
100
Unit
V
mA
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友台半导½有限公司
UMW
R
UMW TL431
Electrical Characteristics
(T
a
=25 °C, V
KA
=V
REF
, I
K
=10mA unless otherwise noted
.
)
Symbol
Parameter
Test Condition
Min.
V
REF
Reference
input Voltage
Deviation of
Reference Input
Voltage Over Full
Temperature Range
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-State Cathode Current
Dynamic
Impedance
TL431xxC/I
TL431xxQ
V
KA
=40V, V
REF
=0
I
K
=1mA to 100mA
f≦1.0KHz
V
KA
=V
REF
,
I
K
=10mA
0.5%
1%
2.483
2.470
Typ.
2.495
2.495
Max.
2.508
2.520
Unit
V
V
REF(dev)
T
min
≦T
a
≦T
max
-
3
17
mV
△V
REF
/△V
KA
I
REF
I
REF(dev)
I
K(min)
I
K(off)
Z
KA
△V
KA
=10V-V
REF
△V
KA
=36V-10V
R
1
=10KΩ, R
2
=∞
R
1
=10KΩ, R
2
=∞
-0.4
-0.4
-
-
-
-
1.8
0.4
2.7
2.0
4
1.2
mV/
V
uA
uA
-
-
-
0.25
0.17
0.27
0.15
0.5
0.9
0.5
0.5
mA
uA
Ω
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友台半导½有限公司
UMW
R
UMW TL431
Test Circuit
Typical Application Circuits
Notes for Typical Application Circuits:
1. For the series regulator applications, add a compensation capacitor C
1
between
CATHODE and REF is strongly recommended to improve the stability of output
voltage.
2. Set Vo according to the following equation: Vo=V
REF
(1+R
1
/R
2
)+I
REF
xR
1
.
3. Choose the Value for R
B
as below:
(1). The maximum limit for R
B
should be such that the cathode current (I
K
) is greater
than the minimum operating current (0.5mA) at V
IN(MIN)
.
(2). The minimum limit for R
B
should be such that the cathode current (I
K
) does not
exceed 100mA under all load conditions, and the instantaneous turn-on value for
I
K
does not exceed 120mA.
B
B
B
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UMW
R
UMW TL431
Typical Characteristics
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