PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 1 - HTC
FEATURES
Programmable Output Voltage to 40V
Guaranteed 0.5% Reference Voltage Tolerance
Low (0.2Ω Typ.) Dynamic Output Impedance
Cathode Current Range(Continuous) – 100 ~ 150 mA
Equivalent Full Range Temperature Coefficient of
50PPM/℃
Temperature Compensated For Operation Over
Full Rate Operating Temperature Range
Low Output Noise Voltage
Fast Turn-on Response
TO-92, SOT-89 or SOT-23 3L Package
APPLICATION
Shunt Regulator
Precision High-Current Series Regulator
High-Current Shunt Regulator
Crowbar Circuit
PWM Converter With Reference
Voltage Monitor
Precision Current Limiter
DESCRIPTION
The TL431 is a three-terminal adjustable shunt regulator
with specified thermal stability over applicable
temperature VREF (Approx. 2.5V) and 40V with two
external resistors. This device has a typical dynamic
output impedance of 0.2Ω. Active output circuitry provides
a very sharp turn-on characteristic, making this device
excellent replacement for zener diodes in many
applications. The TL431 is characterized for operation
from -40℃ to +125℃.
TO-92 PKG
3
2
1
SOT-23 PKG
2
1 3
SOT-89 PKG
1 2 3
PIN 1. Reference 2. Anode 3. Cathode
ORDERING INFORMATION
Device
Package
TL431
TO-92(Bulk)
TL431TA
TO-92(Taping)
TL431SF
SOT-23 3L
TL431F
SOT-89 3L
* Refer to the page 2 for detailed ordering Information,
ABSOLUTE MAXIMUM RATINGS
(Operating temperature range applies unless otherwise specified)
CHARACTERISTIC
SYMBOL
MIN.
UNIT
Cathode Voltage
VKA
-
V
Cathode Current Range(Continuous)
IK
-100
mA
Reference Input Current Range
IREF
-0.05
mA
Junction Temperature Range
TJ
-40
℃
Operating Temperature Range
TOPR
-40
℃
Storage Temperature Range
TSTG
-65
℃
T
O
P
TOP
TOP
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 2 - HTC
RECOMMENDED OPERATING CONDITIONS
CHARACTERISTIC
SYMBOL
MIN.
MAX.
UNIT
Cathode Voltage
VKA
VREF
40
V
Cathode Current
IK
0.5
100
mA
ORDERING INFORMATION
VREF
Package
Tolerance
Order No.
Package Marking
Supplied As
2.495V
TO-92
0.5%
TL431C
TL431-C
Bulk
TL431GC
TL431GC
TL431CTA
TL431-C
Tape
TL431GCTA
TL431GC
1%
TL431A
TL431-A
Bulk
TL431GA
TL431GA
TL431ATA
TL431-A
Tape
TL431GATA
TL431GA
2%
TL431
TL431
Bulk
TL431G
TL431G
TL431TA
TL431
Tape
TL431GTA
TL431G
SOT-23
0.5%
TL431CSF
431
Reel
TL431GCSF
431
1%
TL431ASF
431
Reel
TL431GASF
431
2%
TL431SF
431
Reel
TL431GSF
431
SOT-89
0.5%
TL431CF
431
Reel
1%
TL431AF
431
Reel
2%
TL431F
431
Reel
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 3 - HTC
ORDERING INFORMATION (continued)
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 4 - HTC
PIN CONFIGURATION
TO-92 PKG SOT-23 PKG SOT-89 PKG
PIN DESCRIPTION
Pin No.
TO-92 / SOT-23 / SOT-89
Name
Function
1
Reference
Reference Voltage
2
Anode
Ground
3
Cathode
Input Supply Voltage
TL431 ELECTRICAL CHARACTERISTICS (TA=25℃, unless otherwise specified)
CHARACTERISTIC
SYMBOL
TEST CONDITION
MIN.
TYP.
MAX.
UNIT
Reference Input Voltage
VREF
VKA =VREF,
IK =10mA
TL431C
2.483
2.495
2.507
V
TL431A
2.470
2.495
2.520
TL431
2.440
2.495
2.550
Deviation of
Reference Input Voltage
ΔVREF/ΔT
VKA = VREF, IK =10mA
TA =Full Range
15
30
mV
Ratio of Change in Reference
Input Voltage to the Change in
Cathode Voltage
ΔVREF/ΔVKA
IK =10mA
ΔVKA=10V -VREF
-1.4
-2.7
mV/V
ΔVKA=36V-10V
-1.0
-2.0
Reference Input Current
IREF
IKA=10mA, R1=10㏀, R2=∞
1.8
4.0
uA
Deviation of Reference Input
Current
ΔIREF/ΔT
IK =10mA, R1=10㏀, R2=∞
TA =Full Range
0.4
1.2
uA
Minimum Cathode Current
for Regulation
IK(MIN)
VKA= VREF
0.5
mA
Off-State Cathode Current
IK(OFF)
VKA=36V, VREF=0
0.17
0.90
uA
Dynamic Impedance
ZKA
VKA= VREF, IK =1mA~100mA
f ≤ 1kHz
0.27
0.50
Ω
TOP
TOP
1 2 3
1 3
1
2
2
3
Marking
Side
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 5 - HTC
TEST CIRCUITS
< Fig 1. Test circuit for VKA = VREF > < Fig 2. Test circuit for VKA ≥ VREF >
< Fig 3. Test circuit for IKA(OFF) >
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 6 - HTC
The deviation parameters ΔVREF/ΔT and ΔIREF/ΔT are defined as the differences between the maximum and
minimum values obtained over the recommended temperature range. The average full-range temperature
coefficient of the reference voltage, αVREF, is defined as :
A
6
REF
I(dev)
REF ΔT
10×)
25 at V V
(
=)(ppm/αV ℃
℃
Where :
ΔTA is the recommended operating free-air temperature range of the device.
αVREF can be positive or negative, depending on whether minimum VREF or maximum VREF, respectively, occurs at
the lower temperature.
Example : Maximum VREF=2496mV at 30℃, maximum VREF=2492mV at 0℃, VREF=2495mV at 25℃,
ΔTA=70℃ for TL431C.
℃≈
℃23ppm/
70
10×)
2495mV
4mV
(
=αV
6
REF
Because minimum VREF occurs at the lower temperature, the coefficient is positive.
Calculating Dynamic Impedance
The dynamic impedance is defined as :
KA
KA
KA ΔI
ΔV
=Z
When the device is operating with two external resistors, the total dynamic impedance of the circuit is given by:
( )
R1/R2+1 Z ≈
ΔI
ΔV
=Z KA
'
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 7 - HTC
TYPICAL OPERATING CHARACTERISTICS
Reference Voltage vs. Ambient Temperature Pulse Response
Cathode Current vs. Cathode Voltage Cathode Current vs. Cathode Voltage
Small Signal Voltage Amplification vs. Frequency
0
10
20
30
40
50
60
1k 10k 100k 1000k 10000k
Frequency, f [Hz]
AV-Small Signal Voltage Amplification
(dB)
15kΩ
8.25kΩ
232Ω
10µF
Output
IKA
< Fig 4. TEST Circuit for Voltage Amplification >
IKA = 10mA
TA = 25°C
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 8 - HTC
APPLICATION INFORMATION
1. Shunt Regulator
Note A : R Should provide cathode current 1mA to the TL431 at minimum VI(BATT)
2. Precision High-Current Series Regulator
Note A : R Should provide cathode current≥1mA to the TL431 at minimum VI(BATT)
3. Output Control of a Three-Terminal Fixed Regulator
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 9 - HTC
4. High-Current Shunt Regulator
5. Precision 5-V 1.5A Regulator
6. Efficient 5-V Precision Regulator
NOTE A : RB Should provide cathode current≥1mA to the TL431.
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 10 - HTC
7. PWM Converter With Reference
8. Voltage Monitor
NOTE A : R3 and R4 are selected to provide the desired LED intensity and cathode current ≥1mA to the TL431 at the available VI(BATT).
9. Delay Timer
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 11 - HTC
10. Precision Current Limiter
11. Precision Constant-Current Sink
PROGRAMMABLE PRECISION SHUNT REGULATOR TL431/A/C
Feb. 2019 – Rev.1.8 - 12 - HTC
REVISION NOTICE
The description in this data sheet can be revised without any notice to describe its electrical characteristics properly.