TECHNICAL DATA
Programmable Precision Reference
FEATURES
•
Programmable Output Voltage to 40V
•
Low Dynamic Output Impedance 0.2Ω
•
Sink Current Capability of 0.1 mA to 100 mA
•
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 Response
•
TO-92, SOP- 8, SOT-23, SOT-89 packages
TL431
PIN CONNECTIONS
ANODE
REFERENCE
CATHODE
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 (approximately 2.5 volts) and 40 volts with two external resistors. These
devices have a typical dynamic output impedance of 0.2Ω. Active output circuitry provides a very sharp turn-on characteristic,
making these devices excellent replacement for zener diodes in many applications.
o
o
The TL431 is characterized for operation from -25 C to +85 C.
SYMBOL
FUNCTIONAL BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS
(Operating temperature range applies unless otherwise specified)
Characteristic
Cathode Voltage
Cathode Current Range (Continuous)
Reference Input Current Range
Power Dissipation at 25 C:
o
SOP, TO – 92 Package (R
JA
= 178 C/W)
SOT Package (R
JA
= 625
o
C/W)
Junction Temperature Range
Operating Temperature Range
Storage Temperature Range
o
Symbol
V
KA
I
K
I
REF
P
D
Value
40
-100 ~ 150
0.05 ~ 10
0.7
0.2
Unit
V
mA
mA
W
W
o
o
o
T
J
T
g
T
stg
-40 ~ 150
-40 ~ +85
-65 ~ +150
C
C
C
Rev. 00
TL431
RECOMMENDED OPERATING CONDITIONS
Characteristic
Cathode Voltage
Cathode Current
Symbol
V
KA
I
K
Test Condition
Min
V
REF
0.5
Typ
Max
40
100
Unit
V
mA
ELECTRICAL CHARACTERISTICS
(T
a
= 25
o
C, V
KA
= V
REF
, I
K
= 10mA unless otherwise specified)
Characteristic
Reference Input Voltage
Symbol
V
REF
Test Condition
V
KA
= V
REF
, I
K
= 10mA
2.440
TL431 (2%)
TL431-A (1%)
TL431-C (0.5%)
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
V
REF(dev)
T
min
≤
Ta
≤
T
max
3
17
MV
2.470
2.482
2.495
2.495
2.495
2.550
2.520
2.508
V
Min
Typ
Max
Unit
Δ
V
REF
Δ
V
K A
I
REF
I
REF(dev)
ΔV
KA
= 10V-V
REF
ΔV
KA
= 36V- 10V
R
1
= 10KΩ, R
2
=
∞
R
1
= 10KΩ, R
2
=
∞
-1.4
-1.0
1.8
0.4
-2.7
mV/V
-2.0
4
1.2
㎂
㎂
I
K(min)
I
K(off)
Z
KA
V
KA
= 40 V, V
REF
= 0
I
K
= 10mA to 100 mA , f
≤
1.0KHz
0.25
0.26
0.22
0.5
0.9
0.5
mA
㎂
Ω
TEST CIRCUITS
Figure 1. Test Circuit for V
KA
= V
REF
Figure 2. Test Circuit for V
KA
≥
V
REF
Figure 3. Test Circuit for I
off
INPUT
V
K A
I
K (OFF)
TL431
TL431
BT432
TL431
Rev. 00
TL431
Electrical Characteristics
(Continued)
The average temperature coefficient of the reference input voltage,
∝
V
REF
, is defined as:
Where:
T
2
− T
1
= full temperature change (0-70˚C).
∝
V
REF
can be positive or negative depending on whether the slope is positive or negative.
Example: V
DEV
= 8.0 mV, V
REF
= 2495 mV, T
2
− T
1
= 70˚C, slope is positive.
Note 6:
The dynamic output impedance, r
Z
, is defined as:
When the device is programmed with two external resistors, R1 and R2, (see
Figure 2
), the dynamic output impedance of the overall circuit, r
Z
, is defined as:
Rev. 00
TL431
Equivalent Circuit
Typical Performance Characteristics
Input Current vs V
Z
Thermal Information
Input Current vs V
Z
Dynamic Impedance vs Frequency
Rev. 00
TL431
Typical Performance Characteristics
Stability Boundary Conditions
(Continued)
Note:
The areas under the curves represent conditions that may cause the
device to oscillate. For curves B, C, and D, R2 and V
+
were adjusted to
establish the initial V
Z
and I
Z
conditions with C
L
= 0. V
+
and C
L
were then
adjusted to determine the ranges of stability.
Test Circuit for Curve A Above
Test Circuit for Curves B, C and D Above
Typical Applications
Shunt Regulator
Single Supply Comparator with
Temperature Compensated Threshold
Rev. 00
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