PROGRAMMABLE PRECISION SHUNT REGULATOR
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
TL431Z/AZ/CZ
TO-92 PKG
3
T
O
P
2
1
SOT-23 PKG
2
TOP
APPLICATION
Shunt Regulator
Precision High-Current Series Regulator
High-Current Shunt Regulator
Crowbar Circuit
PWM Converter With Reference
Voltage Monitor
Precision Current Limiter
1
3
SOT-89 PKG
TOP
DESCRIPSION
The TL431Z is a three-terminal adjustable shunt regulator
with specified thermal stability over applicable
temperature V
REF
(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 TL431Z is characterized for operation
from -40℃ to +125℃.
PIN 1. Reference
ORDERING INFORMATION
Device (Marking)
TL431Z
TL431-AZ
TL431-CZ
431Z
431Z
1
2
3
2. Anode
3. Cathode
Package
TO-92
SOT-23 3L
SOT-89 3L
Absolute Maximum Ratings
(Operating temperature range applies unless otherwise specified)
CHARACTERISTIC
Cathode Voltage
Cathode Current Range(Continuous)
Reference Input Current Range
Junction Temperature Range
Storage Temperature Range
Operating Temperature Range
2009 – Obsolete
SYMBOL
V
KA
I
K
I
REF
T
J
T
STG
T
OPR
MIN.
-
-100
0.05
0
-60
-40
MAX.
42
150
10
150
150
125
UNIT
V
mA
mA
℃
℃
℃
-1-
HTC
PROGRAMMABLE PRECISION SHUNT REGULATOR
PIN CONFIGURATION
Marking
Side
2
TL431Z/AZ/CZ
TOP
TOP
1
1 2 3
3
1
2
3
TO-92 PKG
SOT-23 PKG
SOT-89 PKG
PIN DESCRIPTION
Pin No.
1
2
3
TO-92 / SOT-23 / SOT-89
Name
Reference
Anode
Cathode
Function
Reference Voltage
Ground
Input Supply Voltage
TL431Z ELECTRICAL CHARACTERISTICS
(T
A
=25℃, unless otherwise specified)
CHARACTERISTIC
SYMBOL
TEST CONDITION
TL431CZ
MIN.
2.483
2.47
2.44
TYP.
2.495
2.495
2.495
3
-1.4
-1.0
1.8
0.4
MAX.
2.507
2.52
2.55
17
-2.7
-2.0
4.0
1.2
UNIT
Reference Input Voltage
V
REF
V
KA
=V
REF
,
I
K
=10mA
TL431AZ
TL431Z
V
Deviation of
Reference Input Voltage
Ratio of Change in Reference
Input Voltage to the Change in
Cathode Voltage
Reference Input Current
Deviation of Reference Input
Current
Minimum Cathode Current
for Regulation
Off-State Cathode Current
Dynamic Impedance
ΔV
REF
/ΔT
V
KA
= V
REF
, I
K
=10mA
T
A
=Full Range
ΔV
KA
=10V -V
REF
mV
ΔV
REF
/ΔV
KA
I
REF
ΔI
REF
/ΔT
I
K
=10mA
ΔV
KA
=36V-10V
I
KA
=10mA, R
1
=10㏀, R
2
=∞
I
K
=10mA, R
1
=10㏀, R
2
=∞
T
A
=Full Range
V
KA
= V
REF
V
KA
=42V, V
REF
=0
V
KA
= V
REF
, I
K
=1mA~100mA
f
≤
1kHz
0.17
0.27
mV/V
uA
uA
I
K(MIN)
I
K
OFF
Z
KA
0.5
0.9
0.5
mA
uA
Ω
2009 – Obsolete
-3-
HTC
PROGRAMMABLE PRECISION SHUNT REGULATOR
TL431Z/AZ/CZ
The deviation parameters
ΔV
REF
/ΔT
and
ΔI
REF
/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,
αV
REF
, is defined as :
Where :
ΔT
A
is the recommended operating free-air temperature range of the device.
αV
REF
can be positive or negative, depending on whether minimum V
REF
or maximum V
REF
, respectively, occurs at
the lower temperature.
Example : Maximum V
REF
=2496mV at 30
℃
, maximum V
REF
=2492mV at 0
℃
, V
REF
=2495mV at 25
℃
,
ΔT
A
=70
℃
for TL431CZ.
a
V
REF
⎛
4
mV
⎞
6
⎜
⎟ ×
10
23
ppm
2495
mV
⎠
=⎝
≈
70
°
C
°
C
Because minimum V
REF
occurs at the lower temperature, the coefficient is positive.
Calculating Dynamic Impedance
The dynamic impedance is defined as :
Z
KA
=
Δ
V
KA
Δ
I
KA
When the device is operating with two external resistors, the total dynamic impedance of the circuit is given by :
Z
'
=
R
1
⎞
Δ
V
⎛
≈
Z
KA
⎜
1
+
⎟
R
2
⎠
Δ
I
⎝
2009 – Obsolete
-5-
HTC
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