Precision Adjustable
Shunt Reference
TL431
FEATURES
••
Trimmed 1% Bandgap Reference
••
Nominal Temperature Range Extended to 105
o
C
••
Temperature-Compensated: 30ppm/
o
C
••
Internal Amplifier with 150mA Capability
••
Low Output Noise
••
Low Frequency Dynamic Output Impedance
DESCRIPTION
The TL431 is an adjustable shunt regulator designed to act as
an open-loop error amplifier with a 2.5V temperature
compensated reference. Its highly accurate 1% bandgap
reference is perfect for applications requiring stability and
accuracy over temperature and life.
Sharp turn-on characteristics and a low temperature coefficient
make the TL431 an excellent replacement for many zener
diode applications, programmable to any value greater than
2.5V and up to 36V by using two external resistors. As a
combination error amplifier and reference, it can be used to
manage control loops such as switching power supplies.
ORDERING INFORMATION
Part
Package
Temperature Range
TL431LP
TO-92
0 to 105
o
C
TL431D
8-Pin Plastc SOIC
0 to 105
o
C
TL431S
SOT-89
0 to 105
o
C
CORPORATION
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
CATHODE
ANODE
REFERENCE
TO-92 (LP)
1G-33
SOIC (D)
8
7
6
5
1
2
3
4
REFERENCE
ANODE
ANODE
N/C
CATHODE
ANODE
ANODE
N/C
1G-34
1G-35
CATHODE
ANODE
REFERENCE
SOT-89 (S)
PIN CONFIGURATION (Top View)
TL431
ABSOLUTE MAXIMUM RATINGS
SYMBOL
PARAMETER
RATING
UNITS
V
KA
Cathode-Anode Reverse Breakdown
37
V
I
AK
Anode-Cathode Forward Current
1
A
I
KA
Operating Cathode Current
250
mA
I
REF
Reference Input Current
10
mA
P
D
Continuous Power at 25
o
C
TO-92
8L
SOIC
SOT-89
775
750
1000
mW
mW
mW
T
J
Junction Temperature
150
o
C
T
STG
Storage Temperature
–65 to 150
o
C
T
L
Lead Temperature, Soldering 10 Seconds
300
o
C
Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification
is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability.
RECOMMENDED CONDITIONS
SYMBOL
PARAMETER
RATING
UNIT
V
KA
Cathode Voltage
V
REF
to 20
V
I
K
Cathode Current
10
mA
TYPICAL THERMAL RESISTANCE
PACKAGE
θ
JA
θ
JC
TYPICAL DERATING
TO-92
160
o
C/W
80
o
C/W
6.3mW/
o
C
SOIC
175
o
C/W
45
o
C/W
5.7mW/
o
C
SOT-89
110
o
C/W
8
o
C/W
9.1mW/
o
C
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
1G-36
ANODE (A)
CATHODE (K)
2.5V
REFERENCE (R)
+
–
FUNCTIONAL BLOCK DIAGRAM
CORPORATION
TL431
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
ELECTRICAL CHARACTERISTICS
Electrical Characteristics are guaranteed over full junction temperature range (0 to 105
o
C). Ambient temperature must be derated based on
power dissipation and package thermal characteristics. The conditions are: V
KA
= V
REF
and I
K
= 10mA unless otherwise stated.
SYMBOL
PARAMETER
MIN
TYP
MAX
UNIT
TEST CIRCUIT
TEST CONDITION
V
REF
Reference Voltage
2.470
2.495
2.520
V
1
T
A
= 25
o
C
2.449
2.541
V
1
Over Temp.
TC
∆
V
REF
with Temp.*
0.07
0.20
mV/
o
C
1
∆
V
REF
∆
V
K
Ratio of Change in V
REF
to
Cathode Voltage
–2.7
–1.0
mV/V
2
V
REF
to 10V
–2
–0.4
0.3
10V to 36V
I
REF
Reference Input Current
0.7
4
µ
A
2
∆
I
REF
I
REF
Temp Deviation
0.4
1.2
µ
A
2
Over Temp.
I
K(MIN)
Min I
K
for Regulation
0.4
1
mA
1
I
K(OFF)
Off State Leakage
0.04
250
nA
3
V
REF
= 0V, V
KA
= 36V
Z
KA
Dynamic Output Impedance
0.15
0.5
Ω
1
f
≤
1kHz, I
K
= 1 to 150mA
0
15
30
45
60
75
90
105
TEMPERATURE (˚C)
0.07 mV/˚C
0.003 %/˚C
27 ppm/˚C
0.5
5000
0
0
0
mV
%
ppm
–10
∆
V
REF
∆
T
1G-37
•
TC in
mV/
o
C
=
∆
V
REF
(
mV
)
∆
T
A
•
TC in
%/
o
C
=
∆
V
REF
V
REF
at
25
o
C
x 100
∆
T
A
•
TC in
ppm/
o
C
=
∆
V
REF
V
REF
at 25
o
C
x 10
6
∆
T
A
*CALCULATING AVERAGE TEMPERATURE COEFFICIENT (TC)
TEST CIRCUITS
IN
V
KA
V
K
I
1G-38
REF
I
REF
= V
REF
I
IN
V
KA
V
2
R
1
R
REF
(V
)
K
I
1G-39
IN
V
KA
V
K(OFF)
I
1G-40
TEST CIRCUIT 1
TEST CIRCUIT 2
TEST CIRCUIT 3
CORPORATION
TL431
TYPICAL PERFORMANCE CURVES
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
100
0.01
–60
1G-43
OFF STATE LEAKAGE
–30
0
30
60
90
120
10
1
0.1
CURRENT (nA)
V
KA
= 36V
V
REF
= 0V
– AMBIENT TEMPERATURE (˚C)
T
A
– OFF STATE CATHODE
I
Z
off
150
–100
–2
3
1G-42
HIGH CURRENT OPERATING
CHARACTERISTICS
75
50
25
0
–25
–50
–75
125
100
2
1
0
–1
– CATHODE VOLTAGE (V)
V
KA
TEMPERATURE RANGE: –55 to 125˚C
V
KA
= V
REF
– CATHODE CURRENT (m
A)
I
K
2.54
2.46
–60
1G-44
TEMPERATURE COEFFICIENT AS
A FUNCTION OF TRIM VALUE
–30
2.47
2.48
2.49
2.50
2.51
2.52
2.53
0
30
60
90
120
V
RE
F
–
RE
F
E
RE
NCE VOLTAGE (
V
)
– AMBIENT TEMPERATURE
T
A
V
KA
= V
REF
I
K = 10mA
V
REF
= 2.503V AT 25˚C
V
KA
– CATHODE VOLTAGE (V)
– CATHODE CURRENT (
µ
A)
I
K
900
–200
–1.0
3.0
1G-41
LOW CURRENT OPERATING
CHARACTERISTICS
1.0
0
2.0
–100
800
700
600
500
400
300
200
100
0
125˚C
–55˚C
25˚C
V
= V
REF
KA
TEMPERATURE RANGE: –55 to 125˚C
0
–50
0
30
1G-46
REFERENCE VOLTAGE
LINE REGULATION
3
6
9
12 15 18 21 24 27
–10
–20
–30
–40
VOLTAGE (mV)
– CHANGE IN REFERENCE
V
REF
– CATHODE VOLTAGE (V)
V
KA
I
K
= 10mA
TEMPERATURE RANGE: –55 to 125˚C
–55˚C
0˚C
25˚C
75˚C
125˚C
3.0
0
–60
1G-45
REFERENCE
INPUT CURRENT
–30
0
30
60
90
120
2.5
2.0
1.5
1.0
0.5
CURRENT (
µ
A)
– REFERENCE INPUT
I
REF
T
A
– AMBIENT TEMPERATURE (˚C)
R1 = 10k
Ω
R2 =
∞
I
K
= 10mA
CORPORATION
TL431
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
TYPICAL PERFORMANCE CURVES (continued)
70
0
10
1G-47
NOISE VOLTAGE
100k
f – FREQUENCY (Hz)
60
50
40
30
20
10
10k
1k
100
NOISE VOLTAGE nV/
Hz
V
KA
= V
REF
= 10mA
T
A
= 25˚C
I
K
0.150
0.0
–60
1G-48
LOW FREQUENCY DYNAMIC
OUTPUT IMPEDANCE
–30
0
30
60
90
120
0.125
0.100
0.075
0.050
0.025
– DYNAMIC IMPEDANCE (
Ω
)
Z
KA
V
KA
= V
REF
= 1 TO 100mA
f
≤
1kHz
I
KA
– FREE AIR TEMPERATURE
T
A
100
0.01
1k
1G-49
DYNAMIC OUTPUT
IMPEDANCE
10M
f – FREQUENCY (Hz)
1M
100k
10k
10
1.0
0.1
– DYNAMIC IMPEDANCE (
Ω
)
Z
KA
T
A
= 25˚C
= 1 TO 100mA
I
K
70
0
1k
1G-50
SMALL SIGNAL GAIN
vs FREQUENCY
10M
f – FREQUENCY (Hz)
60
50
40
30
20
10
1M
100k
10k
I
K = 10mA
G
A
IN
(dB)
– SMALL SIG
N
AL V
O
LTAGE
A
V
T
A
= 25˚C
1H-01
K
I
230
Ω
GND
OUT
15k
8.25k
9
µ
F
CORPORATION
TL431
100
0
10
10
1H-04
7
STABILITY BOUNDARY
CONDITIONS
90
80
70
60
50
40
30
20
10
10
10
10
10
10
10
6
5
4
3
2
1
0
T
A
= 25˚C
A
C
D
– CATHODE CURRENT (mA)
I
K
B
A: V
KA
= V
REF
B: V
KA
= 5V AT I
K
= 10mA
C: V
KA
= 10V AT I
K
= 10mA
D: V
KA
= 15V AT I
K
= 10mA
STABILITY
REGION
– LOAD CAPACITANCE (pF)
C
L
6
–1
0
1H-02
PULSE RESPONSE
t – TIME (
µ
s)
INPUT AND OUTPUT VOLTAGES (V)
12
1 2 3 4 5
6 7 8
9 10 11
4
3
2
1
0
5
INPUT
OUTPUT
1H-03
GND
OUT
220
Ω
INPUT
MONITOR
50
Ω
f
P
= 100kHz
1H-05
K
I
L
C
150
Ω
10k
TYPICAL PERFORMANCE CURVES (continued)
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
CORPORATION