TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
D
Equivalent Full-Range Temperature
Coefficient . . . 30 ppm/°C
D
0.2-Ω Typical Output Impedance
D
Sink-Current Capability...1 mA to 100 mA
D
Low Output Noise
D
Adjustable Output Voltage...V
ref to 36 V
D
Available in a Wide Range of High-Density
Packages
description
The TL431 and TL431A are 3-terminal adjustable
shunt regulators with specified thermal stability
over applicable automotive, commercial, and
military temperature ranges. The output voltage
can be set to any value between Vref
(approximately 2.5 V) and 36 V with two external
resistors (see Figure 17). These devices have a
typical output impedance of 0.2 Ω. Active output
circuitry provides a very sharp turn-on
characteristic, making these devices excellent
replacements for Zener diodes in many
applications, such as on-board regulation,
adjustable power supplies, and switching power
supplies.
The TL431C and TL431AC are characterized for
operation from 0°C to 70°C, and the TL431I and
TL431AI are characterized for operation from
–40°C to 85°C. The TL431M is characterized for
operation over the full military temperature range
of –55°C to 125°C.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
1
2
3
4
8
7
6
5
CATHODE
ANODE
ANODE
NC
REF
ANODE
ANODE
NC
D PACKAGE
(TOP VIEW)
1
2
3
4
8
7
6
5
CATHODE
NC
NC
NC
REF
NC
ANODE
NC
3212019
910111213
4
5
6
7
8
18
17
16
15
14
NC
NC
NC
ANODE
NC
NC
NC
NC
NC
NC
FK PACKAGE
(TOP VIEW)
NC
CATHODE
NC
NC
NC REF
NC
NC
NC
NC
JG, P, OR PW PACKAGE
(TOP VIEW)
PK PACKAGE
(TOP VIEW)
LP PACKAGE
(TOP VIEW)
NC – No internal connection
REF ANODE CATHODE
CATHODE
ANODE
REF
CATHODE
ANODE
REF
ANODE
KTP PACKAGE
(TOP VIEW)
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright 1998, Texas Instruments Incorporated
On products compliant to MIL-PRF-38535, all parameters are tested
unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
2POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
AVAILABLE OPTIONS
PACKAGED DEVICES
TASMALL
OUTLINE
(D)
CHIP
CARRIER
(FK)
CERAMIC
DIP
(JG)
PLASTIC
FLANGE
MOUNT
(KTP)
TO-226AA
(LP)
PLASTIC
DIP
(P)
SOT-89
(PK)
SHRINK
SMALL
OUTLINE
(PW)
CHIP
FORM
(Y)
0°C
to
70°C
TL431CD
TL431ACD TL431CKTPR TL431CLP
TL431ACLP TL431CP
TL431ACP TL431CPK TL431CPW
–40°C
to
85°C
TL431ID
TL431AID TL431ILP
TL431AILP TL431IP
TL431AIP TL431IPK TL431Y
–55°C
to
125°CTL431MFK TL431MJG
The D and LP packages are available taped and reeled. Add R suffix to device type (e.g., TL431CDR). The KTP and PK packages are only available
taped and reeled. Chip forms are tested at TA = 25°C.
symbol
REF
CATHODEANODE
functional block diagram
CATHODE
REF
ANODE
+
_
Vref
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
equivalent schematic†
ANODE
REF
CATHODE
2.4 kΩ7.2 kΩ
3.28 kΩ
20 pF
4 kΩ
1 kΩ
800 Ω
800 Ω800 Ω
20 pF
150 Ω
10 kΩ
†All component values are nominal.
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
4POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TL431Y chip information
This chip, when properly assembled, displays characteristics similar to those of the TL431C. Thermal
compression or ultrasonic bonding can be used on the doped-aluminum bonding pads. The chip can be
mounted with conductive epoxy or a gold-silicon preform.
Bonding Pad Assignments
Chip Thickness: 15 Mils Typical
Bonding Pads: 4 × 4 Mils Minimum
TJ(max) = 150°C
Tolerances Are ±10%.
All Dimensions Are in Mils.
Pins 2, 3, 6, and 7 Are Connected Together.
Pins 4 and 5 Are Not Connected.
TL431Y
CATHODE
ANODE REF
51
41
(1)
(3)
(2)
(1)
(2) (3)
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
Cathode voltage, VKA (see Note 1) 37 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous cathode current range, IKA –100 mA to 150 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reference input current range –50 µA to 10 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous total power dissipation See Dissipation Rating Tables 1 and 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range, Tstg –65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Case temperature for 60 seconds: FK package 260°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: D, P, or PW package 260°C. . . . . . . . . . . .
Lead temperature 1,6 mm (1/16 inch) from case for 60 seconds: JG, LP, or PK package 300°C. . . . . . . . . .
†Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only , and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may af fect device reliability.
NOTE 1: Voltage values are with respect to the anode terminal unless otherwise noted.
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
DISSIPATION RATING TABLE 1 – FREE-AIR TEMPERATURE
PACKAGE TA = 25°C
POWER RATING DERATING FACTOR
ABOVE TA = 25°CTA = 70°C
POWER RATING TA = 85°C
POWER RATING TA = 125°C
POWER RATING
D725 mW 5.8 mW/°C464 mW 377 mW —
FK 1375 mW 11 mW/°C 880 mW 715 mW 275 mW
JG 1050 mW 8.4 mW/°C 672 mW 546 mW 210 mW
KTP 1800 mW 14.5 mW/°C 1147 mW 943 mW —
LP 775 mW 6.2 mW/°C 496 mW 403 mW —
P1000 mW 8 mW/°C 640 mW 520 mW —
PK 500 mW 4 mW/°C 320 mW 260 mW —
PW 525 mW 4.2 mW/°C336 mW — —
DISSIPATION RATING TABLE 2 – CASE TEMPERATURE
PACKAGE TC = 25°C
POWER RATING DERATING FACTOR
ABOVE TC = 25°CTC = 70°C
POWER RATING TC = 85°C
POWER RATING
PK 3125 mW 25 mW/°C2000 mW 1625 mW
recommended operating conditions
MIN MAX UNIT
Cathode voltage, VKA Vref 36 V
Cathode current, IKA 1 100 mA
C suffix 0 70
Operating free-air temperature range, TAI suffix –40 85 °C
M suffix –55 125
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
6POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating conditions, TA = 25°C (unless otherwise
noted)
TEST TL431C
PARAMETER CIRCUIT TEST CONDITIONS MIN TYP MAX UNIT
Vref Reference voltage 2 VKA = V ref, IKA = 10 mA 2440 2495 2550 mV
VI(dev) Deviation of reference voltage
over full temperature range
(see Figure 1) 2VKA = V ref, IKA = 10 mA,
TA = Full range†4 25 mV
D
VRatio of change in reference voltage ∆VKA = 10 V – Vref –1.4 –2.7
ref
D
VKA to the change in cathode voltage 3IKA = 10 mA ∆VKA = 36 V – 10 V –1 –2 mV
V
Iref Reference current 3 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞2 4 µA
II(dev) Deviation of reference current
over full temperature range
(see Figure 1) 3IKA = 10 mA, R1 = 10 kΩ, R2 = ∞,
TA = Full range†0.4 1.2 µA
Imin Minimum cathode current
for regulation 2 VKA = V ref 0.4 1 mA
Ioff Of f-state cathode current 4 VKA = 36 V, Vref = 0 0.1 1 µA
|zKA|Dynamic impedance (see Figure 1) 1IKA = 1 mA to 100 mA, VKA = Vref,
f ≤ 1 kHz 0.2 0.5 Ω
†Full temperature range is 0°C to 70°C for the TL431C.
The deviation parameters Vref(dev) and Iref(dev) 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:
where:
∆TA 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 = 2496 mV at 30°C, minimum Vref = 2492 mV at 0°C, Vref = 2495 mV at 25°C,
∆TA = 70°C for TL431C
Because minimum Vref occurs at the lower temperature, the coefficient is positive.
Calculating Dynamic Impedance
The dynamic impedance is defined as:
When the device is operating with two external resistors (see Figure 3), the total dynamic impedance of the circuit
is given by:
Maximum Vref
Minimum Vref
∆TA
VI(dev)
Ť
a
Vref
Ťǒ
ppm
°C
Ǔ+ǒ
VI(dev)
Vref at 25°C
Ǔ
106
D
TA
Ť
a
Vref
Ť+ǒ
4mV
2495 mV
Ǔ
106
70°C
[
23 ppm
ń
°C
|zKA|
+
D
VKA
D
IKA
|z
Ȁ
|
+
D
V
D
I
[
|zKA|
ǒ
1
)
R1
R2
Ǔ
Figure 1. Calculating Deviation Parameters and Dynamic Impedance
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating conditions, TA = 25°C (unless otherwise
noted)
TEST TL431I
PARAMETER CIRCUIT TEST CONDITIONS MIN TYP MAX UNIT
Vref Reference voltage 2 VKA = V ref, IKA = 10 mA 2440 2495 2550 mV
VI(dev) Deviation of reference voltage
over full temperature range
(see Figure 1) 2VKA = V ref, IKA = 10 mA,
TA = Full range†5 50 mV
D
VRatio of change in reference voltage ∆VKA = 10 V – Vref –1.4 –2.7
ref
D
VKA to the change in cathode voltage 3IKA = 10 mA ∆VKA = 36 V – 10 V –1 –2 mV
V
Iref Reference current 3 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞2 4 µA
II(dev) Deviation of reference current
over full temperature range
(see Figure 1) 3IKA = 10 mA, R1 = 10 kΩ, R2 = ∞,
TA = Full range†0.8 2.5 µA
Imin Minimum cathode current for
regulation 2 VKA = V ref 0.4 1 mA
Ioff Of f-state cathode current 4 VKA = 36 V, Vref = 0 0.1 1 µA
|zKA|Dynamic impedance (see Figure 1) 2IKA = 1 mA to 100 mA, VKA = Vref,
f ≤ 1 kHz 0.2 0.5 Ω
†Full temperature range is –40°C to 85°C for the TL431I.
electrical characteristics over recommended operating conditions, TA = 25°C (unless otherwise
noted)
TEST TL431M
PARAMETER CIRCUIT TEST CONDITIONS MIN TYP MAX UNIT
Vref Reference voltage 2 VKA = V ref, IKA = 10 mA 2400 2495 2600 mV
VI(dev) Deviation of reference voltage
over full temperature range
(see Figure 1) 2VKA = V ref, IKA = 10 mA,
TA = Full range†22 mV
D
VRatio of change in reference voltage ∆VKA = 10 V – Vref –1.4 –3
ref
D
VKA to the change in cathode voltage 3IKA = 10 mA ∆VKA = 36 V – 10 V –1 –2.3 mV
V
Iref Reference current 3 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞2 8* µA
II(dev) Deviation of reference current
over full temperature range
(see Figure 1) 3IKA = 10 mA, R1 = 10 kΩ, R2 = ∞,
TA = Full range‡1µA
Imin Minimum cathode current
for regulation 2 VKA = V ref 0.4 1.5 mA
Ioff Of f-state cathode current 4 VKA = 36 V, Vref = 0 0.1 3 µA
|zKA|Dynamic impedance (see Figure 1) 1IKA = 1 mA to 100 mA, VKA = Vref,
f ≤ 1 kHz 0.2 0.9* Ω
* On products compliant to MIL-PRF-38535, this parameter is not production tested.
‡Full temperature range is –55°C to 125°C for the TL431M.
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
8POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating conditions, TA = 25°C (unless otherwise
noted)
TEST TL431AC
PARAMETER CIRCUIT TEST CONDITIONS MIN TYP MAX UNIT
Vref Reference voltage 2 VKA = V ref, IKA = 10 mA 2470 2495 2520 mV
VI(dev) Deviation of reference voltage
over full temperature range
(see Figure 1) 2VKA = V ref, IKA = 10 mA,
TA = Full range†4 25 mV
D
VRatio of change in reference voltage ∆VKA = 10 V – Vref –1.4 –2.7
ref
D
VKA to the change in cathode voltage 3IKA = 10 mA ∆VKA = 36 V – 10 V –1 –2 mV
V
Iref Reference current 3 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞2 4 µA
II(dev) Deviation of reference current
over full temperature range
(see Figure 1) 3IKA = 10 mA, R1 = 10 kΩ, R2 = ∞,
TA = Full range†0.8 1.2 µA
Imin Minimum cathode current
for regulation 2 VKA = V ref 0.4 0.6 mA
Ioff Of f-state cathode current 4 VKA = 36 V, Vref = 0 0.1 0.5 µA
|zKA|Dynamic impedance (see Figure 1) 1IKA = 1 mA to 100 mA, VKA = Vref,
f ≤ 1 kHz 0.2 0.5 Ω
†Full temperature range is 0°C to 70°C for the TL431AC.
electrical characteristics over recommended operating conditions, TA = 25°C (unless otherwise
noted)
TEST TL431AI
PARAMETER CIRCUIT TEST CONDITIONS MIN TYP MAX UNIT
Vref Reference voltage 2 VKA = V ref, IKA = 10 mA 2470 2495 2520 mV
VI(dev) Deviation of reference voltage
over full temperature range
(see Figure 1) 2VKA = V ref, IKA = 10 mA,
TA = Full range†5 50 mV
D
VRatio of change in reference voltage ∆VKA = 10 V – Vref –1.4 –2.7
ref
D
VKA to the change in cathode voltage 3IKA = 10 mA ∆VKA = 36 V – 10 V –1 –2 mV
V
Iref Reference current 3 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞2 4 µA
II(dev) Deviation of reference current
over full temperature range
(see Figure 1) 3IKA = 10 mA, R1 = 10 kΩ, R2 = ∞,
TA = Full range‡0.8 2.5 µA
Imin Minimum cathode current
for regulation 2 VKA = V ref 0.4 0.7 mA
Ioff Of f-state cathode current 4 VKA = 36 V, Vref = 0 0.1 0.5 µA
|zKA|Dynamic impedance (see Figure 1) 2IKA = 1 mA to 100 mA, VKA = Vref,
f ≤ 1 kHz 0.2 0.5 Ω
‡Full temperature range is –40°C to 85°C for the TL431AI.
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
9
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating conditions, TA = 25°C (unless otherwise
noted)
TEST TL431Y
PARAMETER CIRCUIT TEST CONDITIONS MIN TYP MAX UNIT
Vref Reference voltage 2 VKA = V ref, IKA = 10 mA 2495 mV
D
VRatio of change in reference voltage ∆VKA = 10 V – Vref –1.4
ref
D
VKA to the change in cathode voltage 3IKA = 10 mA ∆VKA = 36 V – 10 V –1 mV
V
Iref Reference input current 3 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞2µA
Imin Minimum cathode current
for regulation 2 VKA = V ref 0.4 mA
Ioff Of f-state cathode current 4 VKA = 36 V, Vref = 0 0.1 µA
|zKA|Dynamic impedance†2IKA = 1 mA to 100 mA, VKA = V ref,
f ≤ 1 kHz 0.2 Ω
†Calculating dynamic impedance:
The dynamic impedance is defined as:
Ť
zKA
Ť+
D
VKA
D
IKA
When the device is operating with two external resistors (see Figure 3), the total dynamic impedance of the circuit is given by:
|z
Ȁ
|
+
∆V
∆I
[
|zKA|
ǒ
1
)
R1
R2
Ǔ
PARAMETER MEASUREMENT INFORMATION
Ioff
VKA
Input
Figure 4. Test Circuit for Ioff
Vref
Input VKA
IKA
Figure 2. Test Circuit for VKA = Vref
VKA
+
Vref
ǒ
1
)
R1
R2
Ǔ)
Iref
R1
Iref
IKA
VKA
Input
Vref
R1
R2
Figure 3. Test Circuit for VKA > Vref
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
10 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
Table 1. Graphs
FIGURE
Reference input voltage vs Free-air temperature 5
Reference input current vs Free-air temperature 6
Cathode current vs Cathode voltage 7, 8
Off-state cathode current vs Free-air temperature 9
Ratio of delta reference voltage to change in cathode voltage vs Free-air temperature 10
Equivalent input noise voltage vs Frequency 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 16
Table 2. Application Circuits
FIGURE
Shunt regulator 17
Single-supply comparator with temperature-compensated threshold 18
Precision high-current series regulator 19
Output control of a 3-terminal fixed regulator 20
High-current shunt regulator 21
Crowbar circuit 22
Precision 5-V 1.5-A regulator 23
Efficient 5-V precision regulator 24
PWM converter with reference 25
V oltage monitor 26
Delay timer 27
Precision current limiter 28
Precision constant-current sink 29
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
11
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
†Data is applicable only within the recommended operating free-air
temperature ranges of the various devices.
‡Data is for devices having the indicated value of V ref at IKA = 10 mA,
TA = 25°C. Figure 5
2500
2480
2420
2400
–75 –50 –25 0 25 50 75
2540
2580
REFERENCE VOLTAGE
vs
FREE-AIR TEMPERATURE†
2600
100 125
2460
2560
2520
2440
TA – Free-Air Temperature – °C
Vref = 2495 mV‡
Vref = 2440 mV‡
VKA = Vref
IKA = 10 mA Vref = 2550 mV‡
– Reference Voltage – mV
Vref
Figure 6
3
2
1
0
–75 –25 0 50
4
REFERENCE CURRENT
vs
FREE-AIR TEMPERATURE†
5
100 125
–50 25 75
TA – Free-Air Temperature – °C
R1 = 10 kΩ
R2 = ∞
IKA = 10 mA
– Reference Current –ref
IAµ
†Data is applicable only within the recommended operating free-air
temperature ranges of the various devices.
Figure 7
25
0
–50
–75
–100
125
–25
–2 –1 0 1
75
50
100
CATHODE CURRENT
vs
CATHODE VOLTAGE
150
23
VKA – Cathode Voltage – V
VKA = Vref
TA = 25°C
– Cathode Current – mAIKA
Figure 8
400
200
0
–200–1 0 1
600
CATHODE CURRENT
vs
CATHODE VOLTAGE
800
23
VKA = Vref
TA = 25°C
VKA – Cathode Voltage – V
Imin
– Cathode Current –
IKA Aµ
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
Figure 9
1.5
1
0.5
0
–75 –25 0 50
– Off-State Cathode Current –
2
OFF-STATE CATHODE CURRENT
vs
FREE-AIR TEMPERATURE†
2.5
100 125
–50 25 75
Ioff Aµ
TA – Free-Air Temperature – °C
VKA = 36 V
Vref = 0
†Data is applicable only within the recommended operating free-air
temperature ranges of the various devices.
Figure 10
–1.15
–1.25
–1.35
–1.45
–1.05
– 0.95
RATIO OF DELTA REFERENCE VOLTAGE TO
DELTA CATHODE VOLTAGE
vs
FREE-AIR TEMPERATURE†
– 0.85
TA – Free-Air Temperature – °C
–75 –25 0 50 100 125–50 25 75
VKA = 3 V to 36 V
– mV/V
∆Vref ∆VKA
/
†Data is applicable only within the recommended operating free-air
temperature ranges of the various devices.
180
140
120
10010 100 1 k
220
240
f – Frequency – Hz
EQUIVALENT INPUT NOISE VOLTAGE
vs
FREQUENCY
260
10 k 100 k
200
160
– Equivalent Input Noise Voltage – nV/ HzVn
IO = 10 mA
TA = 25°C
Figure 11
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
13
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
19.1 V
VCC
TLE2027
TLE2027
AV = 10 V/mV
VEE
0.1 µF
160 kΩ
820 Ω
(DUT)
TL431
16 Ω
910 Ω2000 µF
1 kΩ
VEE
VCC
1 µF
16 kΩ16 kΩ
1 µF33 kΩ
33 kΩAV = 2 V/V
22 µF
500 µF
To Oscilloscope
–1
–2
–4
–5
–6
3
–3
0123456
1
0
2
EQUIVALENT INPUT NOISE VOLTAGE
OVER A 10-SECOND PERIOD
4
78910
5
6
t – Time – s
f = 0.1 to 10 Hz
IKA = 10 mA
TA = 25°C
– Equivalent Input Noise voltage – µV
Vn
+
–+
–
Figure 12. Test Circuit for Equivalent Input Noise Voltage
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
14 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
SMALL-SIGNAL VOLTAGE AMPLIFICATION
vs
FREQUENCY
9 µF
GND
Output
232 Ω
8.25 kΩ
IKA
15 kΩ
40
20
10
0
60
30
1 k 10 k 100 k 1 M 10 M
50
f – Frequency – Hz
TEST CIRCUIT FOR VOLTAGE AMPLIFICATION
IKA = 10 mA
TA = 25°C
– Small-Signal Voltage Amplification – dBAV
+
–
Figure 13
1 kΩ
50 Ω
GND
Output
IKA
0.1
1 k 10 k 100 k 1 M 10 M
1
f – Frequency – Hz
REFERENCE IMPEDANCE
vs
FREQUENCY
10
100 IKA = 10 mA
TA = 25°C
TEST CIRCUIT FOR REFERENCE IMPEDANCE
– Reference Impedance –
KA
|z | Ω
+
–
Figure 14
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
15
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
3
2
1
0–1 0 1 2 3 4
Input and Output Voltage – V
4
5
PULSE RESPONSE
6
567
Input
Output
TA = 25°C
220 Ω
50 Ω
GND
Output
Pulse
Generator
f = 100 kHz
TEST CIRCUIT FOR PULSE RESPONSE
t – Time – µs
Figure 15
50
40
10
0
0.001 0.01 0.1 1
70
90
STABILITY BOUNDARY CONDITIONS†
100
10
30
80
60
20
TA = 25°C
B
Stable
Stable
A VKA = Vref
B VKA = 5 V
C VKA = 10 V
D VKA = 15 Vf
CL – Load Capacitance – µF
A
C
D
150 Ω
IKA
R1 = 10 kΩ
R2
CL
VBATT
IKA
CLVBATT
150 Ω
TEST CIRCUIT FOR CURVE A
TEST CIRCUIT FOR CURVES B, C, AND D
– Cathode Current – mA
IKA
†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 IKA conditions with CL = 0. VBATT and
CL were then adjusted to determine the ranges of stability.
+
–
+
–
Figure 16
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
16 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
R1
0.1%
R2
0.1%
R
(see Note A)
Vref
VO
TL431
VI(BATT)
RETURN
NOTE A: R should provide cathode current ≥1 mA to the TL431 at minimum VI(BATT).
VO
+ǒ
1
)
R1
R2
Ǔ
Vref
Figure 17. Shunt Regulator
VO
TL431
VI(BATT)
VIT ≈2.5 V GND
Input Von ≈ 2 V
Voff ≈ VI(BATT)
Figure 18. Single-Supply Comparator With Temperature-Compensated Threshold
R
(see Note A)
VO
TL431
VI(BATT)
2N222
2N222
4.7 kΩ
R1
0.1%
R2
0.1%
0.01 µF
30 Ω
VO
+ǒ
1
)
R1
R2
Ǔ
Vref
NOTE A: R should provide cathode current ≥1 mA to the TL431 at minimum VI(BATT).
Figure 19. Precision High-Current Series Regulator
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
17
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
VO
TL431
VI(BATT)
uA7805
IN OUT
Common R1
R2
VO
+ǒ
1
)
R1
R2
Ǔ
Vref
Minimum VO
+
Vref
)
5V
Figure 20. Output Control of a 3-Terminal Fixed Regulator
VO
TL431
VI(BATT)
R1
R2
VO
+ǒ
1
)
R1
R2
Ǔ
Vref
Figure 21. High-Current Shunt Regulator
VO
TL431
VI(BATT)
R1
R2
NOTE A: Refer to the stability boundary conditions in Figure 16 to determine allowable values for C.
C
(see Note A)
Figure 22. Crowbar Circuit
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
18 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
VO ≈ 5 V, 1.5 A
TL431
VI(BATT) LM317
IN OUT
Adjust 243 Ω
0.1%
243 Ω
0.1%
8.2 kΩ
Figure 23. Precision 5-V 1.5-A Regulator
VO ≈ 5 V
TL431
VI(BATT)
27.4 kΩ
0.1%
Rb
(see Note A)
27.4 kΩ
0.1%
NOTE A: Rb should provide cathode current ≥1-mA to the TL431.
Figure 24. Efficient 5-V Precision Regulator
TL431
12 V
VCC
5 V
6.8 kΩ
10 kΩ
10 kΩ
0.1%
10 kΩ
0.1%
X
Not
Used
Feedback
TL598
+
–
Figure 25. PWM Converter With Reference
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
19
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
TL431
VI(BATT)
R3
(see Note A)
R1A R4
(see Note A)
R2BR2A
NOTE A: R3 and R4 are selected to provide the desired LED intensity and cathode current ≥1 mA to the TL431 at the available VI(BATT).
R1B Low Limit
+ǒ
1
)
R1B
R2B
Ǔ
Vref
High Limit
+ǒ
1
)
R1A
R2A
Ǔ
Vref
LED on When Low Limit < VI(BATT) < High Limit
Figure 26. Voltage Monitor
TL431
650 Ω
2 kΩ
C
On
Off
R
12 V
Delay
+
R
C
In
ǒ
12 V
12 V
*
Vref
Ǔ
Figure 27. Delay Timer
TL431
IO
RCL
0.1%
R1
VI(BATT) Iout
+
Vref
RCL
)
IKA
R1
+
VI(BATT)
IO
hFE
)
IKA
Figure 28. Precision Current Limiter
TL431C, TL431AC, TL431I, TL431AI, TL431M, TL431Y
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS005I – JULY 1978 – REVISED AUGUST 1998
20 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
TL431 RS
0.1%
IO
VI(BATT)
IO
+
Vref
RS
Figure 29. Precision Constant-Current Sink
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