DESCRIPTION KEY FEATURES
WINITIAL VOLTAGE REFERENCE ACCURACY OF
0.4% (TL431B)
WSINK CURRENT CAPABILITY 1mA to 100mA
WTYPICAL OUTPUT DYNAMIC IMPEDANCE
LESS THAN 200mΩ;
TYPICAL OUTPUT IMPEDANCE OF THE
TL431B LESS THAN 100mΩ
WADJUSTABLE OUTPUT VOLTAGE FROM 2.5V
TO 36V
WAVAILABLE IN SURFACE-MOUNT PACKAGES
WLOW OUTPUT NOISE
WTYPICAL EQUIVALENT FULL RANGE
TEMPERATURE COEFFICIENT OF 30ppm/°C
WDIRECT PIN-TO-PIN REPLACEMENT FOR
INDUSTRY STANDARD TL431 AND TL1431
The TL431/TL431A/TL431B series
precision adjustable three terminal shunt
voltage regulators are pin-to-pin
compatible with the industry standard
TL431. The output voltage of this
reference is programmable by using two
external resistors from 2.5V to 36V.
These devices offer low output
impedance for improved load regulation.
The typical output impedance of these
devices is 200mΩ. These devices find
application in the feedback path of
switching power supplies, OVP
crowbar circuits, reference for A/D,
D/A, and as zener diodes with
improved turn-on characteristics.
PRECISION PROGRAMMABLE REFERENCES
PRODUCT HIGHLIGHT
PACKAGE ORDER INFORMATION
TA (°C) Initial
Tolerance
Plastic SOIC
8-pin
DM
Plastic TO-92
3-pin
LP
2% TL431CDM TL431CLP
0 to 70 1% TL431ACDM TL431ACLP
0.4% TL431BCDM TL431BCLP
2% TL431IDM TL431ILP
-40 to 85 1% TL431AIDM TL431AILP
0.4% TL431BIDM TL431BILP
TL431/A
& TL431B
R1
R2
V
OUT
V
IN


R1
R2
VO = 1 + * VREF
Note: All surface-mount packages are available in Tape & Reel.
Append the letter "T" to part number. (i.e. TL431CDMT)
TO-92 (LP) package also available in ammo-pack.
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
PRODUCTION DATA SHEET
THE INFINITE POWER OF INNOVATION
TL431/TL431A/TL431B
Copyright © 1999
Rev. 1.3 9/99 1
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
LINFINITY MICROELECTRONICS INC.
NOTE: For current data & package dimensions, visit our web site: http://www.linfinity.com.
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
Copyright © 1999
Rev. 1.3 9/99
2
PRODUCTION DATA SHEET
ABSOLUTE MAXIMUM RATINGS (Note 1)
Cathode to Anode Voltage (VKA) (Note 2) .................................................... -0.3V to 37V
Reference Input Current (IREF) ................................................................... -50µA to 10mA
Continuous Cathode Current (IK) ......................................................... -100mA to 150mA
Operating Junction Temperature
Plastic (DM, LP Packages) .................................................................................... 150°C
Storage Temperature Range ...................................................................... -65°C to 150°C
Lead Temperature ..................................................................................................... 300°C
PACKAGE PIN OUTS
CATHODE
N.C.
ANODE
N.C.
1 8
2 7
3 6
4 5
REF
ANODE
ANODE
N.C.
DM PACKAGE
(Top View)
LP PACKAGE
(Top View)
1. CATHODE
2. ANODE
3. REF
Note 1. Exceeding these ratings could cause damage to the device. All voltages are with respect
to Ground. Currents are positive into, negative out of the specified terminal. Pin
numbers refer to DIL packages only.
Note 2. Voltage values are with respect to the anode terminal unless otherwise noted.
BLOCK DIAGRAM
Cathode (K)
Anode (A)
V
REF
Ref (R)
DM PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θθ
θθ
θJA 165°C/W
LP PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θθ
θθ
θJA 156°C/W
Junction Temperature Calculation: TJ = TA + (PD x θJA).
The θJA numbers are guidelines for the thermal performance of the device/pc-board system.
All of the above assume no ambient airflow
THERMAL DATA
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
3
Copyright © 1999
Rev. 1.3 9/99
PRODUCTION DATA SHEET
ELECTRICAL CHARACTERISTICS (Note 3)
(Unless otherwise specified, these specifications apply over the operating ambient temperatures for TL431C/TL431AC/TL431BC with 0°C ≤ TA ≤ 70°C,
TL431I/TL431AI/TL431BI with -40°C ≤ TA ≤ 85°C.)
Parameter
Symbol
Test Conditions
TL431/431A/431B
Units
Min. Typ. Max.
2440 2495 2550 mV
2470 2495 2520 mV
2490 2500 2510 mV
417 mV
530 mV
417 mV
530 mV
415 mV
520 mV
-1.4 -2.7 mV/V
-1.1 -2 mV/V
24 µA
1.5 1.9 µA
2.3 µA
0.4 1 mA
0.1 1 µA
0.1 1 µA
2µA
0.18 0.5 µA
0.2 0.5 Ω
0.1 0.2 Ω
Note 3. These parameters are guaranteed by design.
Note 4. Ratio of change in reference input voltage
to the change in cathode voltage.
∆V
REF
∆V
KA
Reference Input Voltage TL431 VREF IK = 10mA, VKA = VREF, TA = 25°C
TL431A IK = 10mA, VKA = VREF, TA = 25°C
TL431B IK = 10mA, VKA = VREF, TA = 25°C
Reference Drift TL431C IK = 10mA, VKA = VREF
TL431I IK = 10mA, VKA = VREF
TL431AC ∆VREF IK = 10mA, VKA = VREF
TL431AI ∆VKA IK = 10mA, VKA = VREF
TL431BC IK = 10mA, VKA = VREF
TL431BI IK = 10mA, VKA = VREF
Voltage Ratio, Ref to Cathode TL431, TL431A IK = 10mA, VKA = 2.5V to 36V
(Note 4) TL431B IK = 10mA, VKA = 2.5V to 36V
Reference Input Current TL431,TL431A IREF VKA = VREF, TA = 25°C
TL431B VKA = VREF, TA = 25°C
VKA = VREF, TA = Operating Range
Minimum Operating Current IMIN VKA = VREF to 36V
Off-State Cathode Current TL431 IOFF VKA = VREF to 36V, TA = 25°C
TL431A VKA = VREF to 36V, TA = 25°C
TL431B VKA = VREF to 36V, TA = Operating Range
VKA = 36V, VREF = 0V, TA = 25°C
Dynamic Impedance TL431 | ZKA |V
KA = VREF, IK = 1mA to 100mA, f ≤ 1kHz, TA = 25°C
TL431B VKA = VREF, IK = 1mA to 100mA, f ≤ 1kHz, TA = 25°C
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
Copyright © 1999
Rev. 1.3 9/99
4
PRODUCTION DATA SHEET
Characteristic Curves
FIGURE #
1. REFERENCE INPUT VOLTAGE vs. FREE-AIR TEMPERATURE
2. REFERENCE INPUT CURRENT vs. FREE-AIR TEMPERATURE
3. CATHODE CURRENT vs. CATHODE VOLTAGE
4. CATHODE CURRENT vs. CATHODE VOLTAGE
5. OFF-STATE CATHODE CURRENT vs. FREE-AIR TEMPERATURE
6. RATIO OF DELTA REFERENCE VOLTAGE TO DELTA CATHODE
VOLTAGE vs. FREE-AIR TEMPERATURE
7. EQUIVALENT INPUT NOISE VOLTAGE vs. FREQUENCY
GRAPH / CURVE INDEX FIGURE INDEX
Parameter Measurement Information
FIGURE #
8. TEST CIRCUIT FOR VKA = VREF
9. TEST CIRCUIT FOR VKA > VREF
10. TEST CIRCUIT FOR IOFF
Typical Characteristics
FIGURE #
11. EQUIVALENT INPUT NOISE VOLTAGE OVER A 10-SECOND PERIOD
12. SMALL-SIGNAL VOLTAGE AMPLIFICATION vs. FREQUENCY
13. REFERENCE IMPEDANCE vs. FREQUENCY
14. PULSE RESPONSE
15. STABILITY BOUNDARY CONDITIONS
Application Information
FIGURE #
16. SHUNT REGULATOR
17. SINGLE-SUPPLY COMPARATOR WITH TEMPERATURE-COMPENSATED
THRESHOLD
18. HIGH CURRENT SHUNT REGULATOR
19. CROWBAR CIRCUIT
20. VOLTAGE MONITOR
21. PRECISION CONSTANT-CURRENT SINK
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
5
Copyright © 1999
Rev. 1.3 9/99
PRODUCTION DATA SHEET
CHARACTERISTIC CURVES
FIGURE 2. — REFERENCE CURRENT
vs. FREE-AIR TEMPERATURE
FIGURE 3. — CATHODE CURRENT vs. CATHODE VOLTAGE FIGURE 4. — CATHODE CURRENT vs. CATHODE VOLTAGE
FIGURE 1. — REFERENCE VOLTAGE
vs. FREE-AIR TEMPERATURE
1
0
(T
A
) Ambient Temperature - (°C)
5
(I
REF
) Reference Input Current - (µA)
2
-50 -25 0 25 50 75 100 125
3
I
K
= 10mA
R1 =
I
K
= 10mA
4
TL431/A
TL431B
2.44
2.4
(T
A
) Ambient Temperature - (°C)
(V
REF
) Reference Input Voltage - (V)
-50 -25 0 25 50 75 100 125
V
REF
= V
KA
I
K
= 10mA
2.42
2.46
2.48
2.50
2.52
2.54
2.56
2.58
2.60
VREF = 2550mV
VREF = 2495mV
VREF = 2440mV
TL431B
TL431/A
TL431/A
TL431/A
0
-100
(V
KA
) Cathode Voltage - (V)
150
(I
K
) Cathode Current - (µA)
-2 -1 0 123
50
V
KA
= V
REF
T
A
= 25°C
100
-75
-50
-25
25
75
125
TL431/A
TL431B
0
-200
(VKA) Cathode Voltage - (V)
800
(IK) Cathode Current - (µA)
200
-1 0 123
400
I
MIN
600
V
KA
= V
REF
T
A
= 25°C
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
Copyright © 1999
Rev. 1.3 9/99
6
PRODUCTION DATA SHEET
CHARACTERISTIC CURVES
FIGURE 5. — OFF-STATE CATHODE CURRENT
vs. FREE-AIR TEMPERATURE
0
(TA) Ambient Temperature - (°C)
2.5
(IOFF) Off-State Cathode Current - (µA)
-50 -25 0 25 50 75 100 125
V
KA
= 36V
V
REF
= 0
0.5
1
1.5
2
TL431/A
& TL431B
FIGURE 6. — RATIO OF DELTA REFERENCE VOLTAGE TO DELTA
CATHODE VOLTAGE vs. FREE-AIR TEMPERATURE
-1.25
-1.45
(T
A
) Ambient Temperature - (°C)
-0.85
∆V
REF
/ ∆V
KA
- (mV/V)
-1.15
-50 -25 0 25 50 75 100 125
V
KA
= 3V to 36V
-1.35
-1.05
-0.95
FIGURE 7. — EQUIVALENT INPUT NOISE VOLTAGE
vs. FREQUENCY
120
100
(f) Frequency - (Hz)
260
(VN) Noise Voltage - (nV/ Hz)
140
10 100 1k 10k 100k
200
220
160
180
240
I
O
= 10mA
T
A
= 25°C
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
7
Copyright © 1999
Rev. 1.3 9/99
PRODUCTION DATA SHEET
PARAMETER MEASUREMENT INFORMATION
FIGURE 8 — TEST CIRCUIT FOR VKA = VREF
V
K
A
Input
V
REF
I
K
FIGURE 9 — TEST CIRCUIT FOR VKA > VREF
V
K
A
Input
V
REF
IK
R
1
R
2
I
REF
FIGURE 10 — TEST CIRCUIT FOR IOFF
V
K
A
Input
I
OFF
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
Copyright © 1999
Rev. 1.3 9/99
8
PRODUCTION DATA SHEET
TYPICAL CHARACTERISTICS
-5
-6
(
t
)
Time -
(
s
)
5
(V
N
) Input Noise Voltage - (µV)
-3
02468
1
2
-2
-1
3
f = 0.1 to 10Hz
I
K
= 10mA
T
A
= 25°C
-4
0
4
10
6
FIGURE 11. — EQUIVALENT INPUT NOISE VOLTAGE OVER A 10-SECOND PERIOD
19.1V
1k
910
2000µF
TL431/A
& TL431B (DUT)
2000µF
820
16
500µF
0.1µF
160k
16k
16k
1µF
VCC
VEE
TLE2027
AV = 10V/mV
1µF 33k
33k
VEE
VCC
TLE2027 2.2µF
CRO
1M
AV = 2V/V
Test Circuit for 0.1Hz to 10Hz Equivalent Input Noise Voltage
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
9
Copyright © 1999
Rev. 1.3 9/99
PRODUCTION DATA SHEET
TYPICAL CHARACTERISTICS
FIGURE 12. — SMALL-SIGNAL VOLTAGE AMPLIFICATION
vs. FREQUENCY
9µF
15k
8.25k
230
Output
GND
I
K
Test Circuit for Voltage Amplification
1k 100k 10M
-10
20
(
f
)
Fre
q
uenc
y
-
(
Hz
)
(A
V
) Voltage Amplification - (dB)
0
50
10k 1M
30
40
60
70
10
I
K
= 10mA
T
A
= 25°C
FIGURE 13. — REFERENCE IMPEDANCE vs. FREQUENCY
1k 100k
0.1
10
(
f
)
Fre
q
uenc
y
-
(
Hz
)
(|z
KA
|) Reference Impedance - ()
1
100
10k 1M 10M
I
K
= 1mA to 100mA
T
A
= 25°C
50
1k
I
K
Outpu
t
GND
Test Circuit for Reference Impedance
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
Copyright © 1999
Rev. 1.3 9/99
10
PRODUCTION DATA SHEET
TYPICAL CHARACTERISTICS
FIGURE 14. — PULSE RESPONSE
05
0
(t) Time - (µs)
6
VIN - (V)
2
1
2
2134
4
1
(VKA)
Output Voltage - (V)
0
3
3
5
6
GND
Outpu
t
220
50
Pulse
Generator
f = 100kHz
Test Circuit for Pulse Response
FIGURE 15. — STABILITY BOUNDARY CONDITIONS
CL
150
IK
VBATT
R1=10k
R2
0
40
(C
L
) Load Capacitance - (µF)
(I
K
) Cathode Current - mA
20
50
10
60
70
30
0.001 0.01 0.1 1 10
80
I
K
= 10mA
T
A
= 25°C
90
100
A V
KA
= V
REF
B V
KA
= 5V
C V
KA
= 10V
D V
KA
= 15V
Stable
C*
D*
A*
B*
Stable
*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 VKA and IK conditions with CL = 0. VBATT and CL were
then adjusted to determine the ranges of stability.
CL
IK
VBATT
150
Test Circuit for Curves B, C, and D
Test Circuit for Curve A
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
11
Copyright © 1999
Rev. 1.3 9/99
PRODUCTION DATA SHEET
APPLICATION INFORMATION
Note: R should provide ≥ 1mA cathode current to
the TL431/A & TL1431 at minimum VBATT.
I
K
R1 0.1%
R2 0.1%
V
REF
TL431/A
& TL431
BATT
V
O
R (see Note)


R1
R2
VO = 1 + * VREF
R1
R2
V
BATT V
O
TL431/A
& TL431B
R1
R2
V
BATT VO
C
(see Note)
TL431/A
& TL431B


R1
R2
VO = 1 + * VREF
FIGURE 18 — HIGH CURRENT SHUNT REGULATOR FIGURE 19 — CROWBAR CIRCUIT
Note: Refer to the stability boundary conditions in
Figure 15 to determine allowable values for C.
FIGURE 16 — SHUNT REGULATOR FIGURE 17 — SINGLE-SUPPLY COMPARATOR WITH
TEMPERATURE-COMPENSATED THRESHOLD
Input V
ON
2V
V
OFF
V
BAT
T
GND
V
BATT
V
O
TL431/A
& TL431B
P
RECISION
P
ROGRAMMABLE
R
EFERENCES
TL431/TL431A/TL431B
PRODUCT DATABOOK 1996/1997
Copyright © 1999
Rev. 1.3 9/99
12
PRODUCTION DATA SHEET
APPLICATION INFORMATION
R1A
R2A
12V
(Note)
R2B
R3 (see Note)
R4
TL431/A
& TL431B
R1B
R2B
Low Limit = 1 + * VREF


R1B
R2B
High Limit = 1 + * VREF


Note: R3 and R4 are selected to provide the desired LED intensity and ≥ 1mA
cathode current to the TL431/A & TL431B at the available V+.
FIGURE 20 — VOLTAGE MONITOR FIGURE 21 — PRECISION CONTANT-CURRENT SINK
LED On when
Low Limit < VBATT < High Limit 

VREF
RS
IO =
RS
0.1
%
VBATT
IO
T
L431/A
&
TL431B
PRODUCTION DATA - Information contained in this document is proprietary to LinFinity, and is current as of publication date. This document
may not be modified in any way without the express written consent of LinFinity. Product processing does not necessarily include testing of
all parameters. Linfinity reserves the right to change the configuration and performance of the product and to discontinue product at any time.