AIC431/TL431A/TL431
Adjustable Precision Shunt Regulator
Analog Integrations Corporation 4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan
DS-431-07 012102
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
1
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FEATURES
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Precision Reference Voltage.
AIC431
:2.495V
0.5%
TL431A :2.495V
1.0%
TL431
:2.495V
1.6%
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Sink Current Capability: 200mA.
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Minimum Cathode Current for Regulation: 250
A.
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Equivalent Full-Range Temperature Coefficient:
50 ppm/
C.
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Fast Turn-On Response.
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Low Dynamic Output Impedance: 0.08
.
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Adjustable Output Voltage.
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Low Output Noise.
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Space Saving Packages: SOT-89, SOT-23, TO-
92 and SO-8.
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APPLICATIONS
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Linear Regulators.
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Adjustable Supplies.
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Switching Power Supplies.
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Battery Operated Computers.
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Instrumentation.
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Computer Disk Drivers.
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TYPICAL APPLICATION CIRCUIT
V
IN
AIC431
+
V
OUT
R1
R2
+
C2
C1
R3
V
OUT
=(1+R1/R2)V
REF
Precision Regulator
n
DESCRIPTION
The AIC431, TL431A and TL431 are 3-
terminal adjustable precision shunt regulators
with guaranteed temperature stability over the
applicable extended commercial temperature
range. The output voltage may be set at any
level greater than 2.495V (V
REF
) up to 30V
merely by selecting two external resistors
that act as a voltage divider network. These
devices have a typical output impedance of
0.08
. Active output circuitry provides a very
sharp turn-on characteristics, making these
devices excellent improved replacements for
zener diodes in many applications.
The precise
0.5% reference voltage toler-
ance of the AIC431 makes it possible in
many applications to avoid the use of a vari-
able resistor, consequently saving cost and
eliminating drift and reliability problems asso-
ciated with it.
AIC431/TL431A/TL431
2
n
ORDERING INFORMATION
PIN CONFIGURATION
SOT-89 (CX)
FRONT VIEW
1: VREF
2: ANODE
3: CATHODE
1
2
3
1
2
3
TO-92 (CZ)
FRONT VIEW
1: VREF
2: ANODE
3: CATHODE
ANODE
REF
ANODE
NC
ANODE
ANODE
NC
CATHODE
1
3
4
2
8
6
5
7
SO-8
TOP VIEW
SOT-23 (CUN)
FRONT VIEW
1: CATHODE
2: VREF
3: ANODE
SOT-23 (CUS)
FRONT VIEW
1: VREF
2: CATHODE
3: ANODE
1
2
3
3
1
2
PACKING TYPE
TR: TAPE & REEL
TB: TUBE (for SO-8)
BG: BAG
PACKAGE TYPE
S: SMALL OUTLINE
US: SOT-23
UN: SOT-23
X: SOT-89
Z: TO-92
AIC431 CXXX
TL431A CXXX
TL431
CXXX
Example: AIC431CSTR
in SO-8 Package & Taping &
Reel Packing Type
(CS is not available in BAG
packing type.)
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ABSOLUTE MAXIMUM RATINGS
Cathode Voltage ........... ... ... ... ... .................. ... ... ... ... ..... ... ... ...............................30V
Continuous Cathode Current ...................... ... ... ... .... ... ...................... -10mA ~ 250mA
Reference Input Current Range
.......... ... ... ... ........... ... ............. ... ... ... ... ... ... ... 10mA
Operating Temperature Range, T
A
.......... ... ... ... ............ ............ ... ... ... ... . -40
C ~ 85
C
Lead Temperature .......... ... ... ... ..................... ... ... ... ... ... ..... ... ... ... ... ... ... ... ... . 260
C
Storage Temperature .......... ... ... ... ..................... ... ... ... ... ..... ... ... ... ... .. -65
C ~ 150
C
Power Dissipation (Notes 1, 2)
SOT-89 Package ............ ... ... ... ...... 0.80W
TO-92 Package ... .......... ... ... ... ....... 0.78W
Note 1: TJ, max = 150
C.
Note 2: Ratings apply to ambient temperature at 25
C.
AIC431/TL431A/TL431
3
n
TEST CIRCUITS
V
REF
I
REF
I
Z
V
Z
I
IN
IN
AIC431
R2
R1
V
REF
I
REF
I
Z
V
Z
IN
I
IN
AIC431
Note: V
Z
=V
REF
(1+R1/R2)+I
REF
xR1
Fig. 1 Test Circuit for V
Z
=V
REF
Fig. 2 Test Circuit for V
Z
>V
REF
IN
V
Z
I
Z(OFF)
AIC431
Fig. 3 Test Circuit for off-state Current
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ELECTRICAL CHARACTERISTICS
(T
A
=25
C, unless otherwise specified.)
PARAMETER
TEST CONDITIONS
SYMBOL
MIN.
TYP.
MAX.
UNIT
V
Z
=V
REF
,
AIC431
2.482
2.495
2.508
I
IN
=10mA (Fig. 1)
TL431A
2.470
2.495
2.520
Reference Voltage
TL431
V
REF
2.455
2.495
2.535
V
V
Z
= V
REF
, I
IN
=10mA,
T
A
= 0
C~ +70
C (Fig. 1)
9.0
20
Deviation of Reference
Input Voltage Over
Temperature (Note 3)
T
A
= -40
C~ +85
C (Fig. 1)
V
DEV
9.0
50
mV
V
Z
=10V-V
REF
-0.5
-2.0
mV/V
Ratio of the Change in Refer-
ence Voltage to the Change
in Cathode voltage
I
Z
=10mA
(Fig. 2)
V
Z
=30V-10V
V
REF
V
Z
-0.35
-1.5
mV/V
AIC431/TL431A/TL431
4
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ELECTRICAL CHARACTERISTICS
(Continued)
PARAMETER
TEST CONDITIONS
SYMBOL
MIN.
TYP.
MAX.
UNIT
Reference Input Current
R1
=10K
, R2=
,
I
IN
=10mA (Fig. 2)
I
REF
0.8
3.5
A
Deviation of Reference Input
Current over Temperature
R1
=10K
, R2=
,
I
IN
=10mA
T
A
=-40
C ~ +85
C (Fig. 2)
I
REF
0.3
1.2
A
Minimum Cathode current for
Regulation
V
Z
=V
REF
(Fig. 1)
I
Z(MIN)
0.25
0.5
mA
Off-State Current
V
Z
=20V, V
REF
=0V (Fig. 3)
I
Z(OFF)
0.1
1.0
A
Dynamic Output Impedance
(Note 4)
V
Z
=V
REF
F<1KHz (Fig. 1)
R
Z
0.08
0.3
T
2
T
1
V
MAX
V
DEV
= V
MAX
-V
MIN
V
MIN
TEMPERATURE
Note 3. Deviation of reference input voltage, V
DEV
, is de-
fined as the maximum variation of the reference input
voltage over the full temperature range.
The average temperature coefficient of the reference in-
put voltage,
V
REF
is defined as:
T1
T2
10
C)
25
(at
V
V
T1
T2
6
10
C)
25
(at
V
V
-
V
C
ppm
V
6
REF
DEV
REF
MIN
MAX
REF
-
=
-
=
Where:
T
2
-
T
1
=full temperature change.
V
REF
can be positive or negative depending on
whether the slope is positive or negative.
Example: V
DEV
= 9.0mV, V
REF
= 2495mV,
T
2
-
T
1
= 70
C, slope is negative.
C
50ppm/
V
C
70
6
10
2495mV
9.0mV
REF
-
=
=
Note 4. The dynamic output impedance, Rz, is de-
fined as:
R
Z
=
Z
Z
V
I
When the device is programmed with two external re-
sistors, R1 and R2, (see Fig. 2), the dynamic output
impedance of the overall circuit, is defined as:
[ ]
R2
R1
1
Rz
I
V
z
r
+
=
AIC431/TL431A/TL431
5
n
TYPICAL PERFORMANCE CHARACTERISTICS
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
-600
-400
-200
0
200
400
600
800
1000
I
Z(MIN)
V
Z
=V
REF
T
A
=25
C
Fig. 4 Cathode Current vs. Cathode Voltage
Cathode Current (
A)
Cathode Voltage (V)
-40
-20
0
20
40
60
8 0
100
120
2.40
2.42
2.44
2.46
2.48
2.50
2.52
2.54
2.56
2.58
Fig. 5 Reference Voltage vs. Temperature
V
Z
=V
REF
I
Z
=10mA
Reference
Voltage (V)
Temperature (
C)
V
REF
=2.535V
V
REF
=2.495V
V
REF
=2.455V
-40
-20
0
20
40
60
80
100
120
0.70
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
Fig. 6 Reference Input Current vs. Temperature
Reference
Input
Current (
A)
Temperature (
C)
R1=10K
R2=
I
Z
=10mA
-40
-20
0
20
40
60
80
100
120
0.00
0.04
0.08
0.12
0.16
0.20
0.24
0.28
V
Z
=V
REF
I
Z
=1mA to100mA
F <1KHz
Fig. 7 Dynamic Impedance vs. Temperature
Dynamic
Impedance (
)
Temperature (
C)
0
5
10
15
2 0
25
3 0
35
40
-6
-5
-4
-3
-2
-1
0
Fig. 8 Change in Reference Voltage vs. Cathode Voltage
Change
in
Reference
Voltage (mV)
Cathode Voltage (V)
I
Z
=10mA
T
A
=25
C
-40
-20
0
20
40
60
80
100
120
0.0
0.5
1.0
1.5
2.0
2.5
Fig. 9 Off-State Cathode Current vs. Temperature
Off-State Cathode Current (
A)
Temperature (
C)
V
REF
=0V
V
Z
=30V
AIC431/TL431A/TL431
6
n
TYPICAL PERFORMANCE CHARACTERISTICS
(Continued)
10
100
1k
10k
100k
1M
10M
-10
0
10
20
30
40
50
60
70
80
Av
I
Z
=10mA
T
A
=25
C
Fig. 10 Small Signal Voltage Amplification vs. Frequency
Small Signal Voltage Amplification (dB)
Frequency (Hz)
R1
10K
R2
250
+
V
IN
C
IN
47
F
V1
AIC431
Output
Fig. 11 Test Circuit For Frequency Response
Fig. 12 Pulse Response
Input
Output
RA
50
RB
220
AIC431
OUTPUT
Pulse
Generator
f=100kHz
Fig. 13 Test Circuit For Pulse Response
1E-4
1E-3
0.01
0.1
1
10
0
20
40
60
80
100
Fig. 14 Stability Boundary Conditions
Cathode Current (
mA)
Load Capacitance (
F)
V
Z
=V
REF
Stable
Stable
CL
VIN
R
150
AIC431
V
Z
Fig. 15 Test Circuit for Stability Boundary
The areas between the curves represent condition that
may cause the device oscillate
AIC431/TL431A/TL431
7
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TYPICAL PERFORMANCE CHARACTERISTICS
(Continued)
1 K
10K
100K
1M
0.1
1
10
Iz=10mA
T
A
=25
C
Fig. 16 Dynamic impedance vs. Frequency
Dynamic
Impedance
(
)
Frequency (Hz)
R1
50
+
AC
3V
R2
50
AIC431
GND
Output
+
Fig. 17 Test Circuit for Dynamic Impedance
-
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SYMBOL
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BLOCK DIAGRAM
ANODE (A)
REF (R)
CATHODE (C)
AIC431
ANODE (A)
CATHODE (C)
REF (R)
+
-
2.495V
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PIN DESCRIPTIONS
CATHODE Pin -
Sinks current with a range from 250
A to 200mA for normal applications.
VREF Pin
-
Providing V
REF
=2.495V (typ.) for adjustable output voltage.
ANODE Pin
-
Anode pin sources current for normal application. The current value is the same as
Cathode pin.
AIC431/TL431A/TL431
8
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APPLICATION EXAMPLES
V
IN
R1A
R2A
R1B
R2B
AIC431
AIC431
R3
R4
R1
ON
OFF
C
V
IN
+
AIC431
R3
R2
LED Turn on when Low Limit<V
IN
< High Limit
Low Limit
V
REF
(1+R1B/R2B)
Delay=R x C x
l
n
(
V
V
V
IN
IN
REF
-
)
High Limit
V
REF
(1+R1A/R2A)
Fig. 18 Voltage Monitor
Fig. 19 Delay Timer
R
CL
I
OUT
V
IN
AIC431
R1
R
V
IN
S
I
OUT
AIC431
R1
I
OUT
=V
REF
/ R
CL
I
OUT
=V
REF
/R
S
Fig. 20 Current Limiter or Current Source
Fig. 21 Constant-Current Sink
V
OUT
R1
R2
V
IN
AIC431
R
IN
R3
V
IN
R2
V
OUT
FUSE
AIC431
R3
R1
V
OUT
(1+R1/R2) x V
REF
V
LIMIT
(1+R1/R2) x V
REF
Fig 22. Higher-Current Shunt Regulator
Fig 23 Crow Bar
AIC431/TL431A/TL431
9
n
APPLICATION EXAMPLES
(Continued)
R1A
R2A
R2B
R1B
V
IN
Output turn ON when
Low Limit <V
IN
< High Limit
+
V
BE
AIC431
AIC431
R3
R4
R5
C1
Low Limit
V
REF
( 1+ R1B/ R2B )+ V
BE
High Limit
V
REF
( 1+ R1A/ R2A )
Fig 24. Over-Voltage/Under-Voltage Protection Circuit
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PHYSICAL DIMENSIONS
l
8 LEAD PLASTIC SO (unit: mm)
SYMBOL
MIN
MAX
A
1.35
1.75
A1
0.10
0.25
B
0.33
0.51
C
0.19
0.25
D
4.80
5.00
E
3.80
4.00
e
1.27(TYP)
H
5.80
6.20
L
0.40
1.27
D
H
e
A
B
A1
C
E
L
AIC431/TL431A/TL431
10
l
SOT-23 (unit: mm)
SYMBOL
MIN
MAX
A
1.00
1.30
A1
--
0.10
A2
0.70
0.90
b
0.35
0.50
C
0.10
0.25
D
2.70
3.10
E
1.40
1.80
e
1.90 (TYP)
H
2.60
3.00
L
0.37
--
H
A1
A
A2
b
1
L
C
D
E
e
1
1
9
l
SOT-23 MARKING
Part No.
Marking
Part No.
Marking
AIC431CUN
AC1N
AIC431CUS
AC1S
TL431CUN
AC2N
TL431CUS
AC2S
TL431ACUN
AC3N
TL431ACUS
AC3S
l
SOT-89 (unit: mm)
SYMBOL
MIN
MAX
A
1.40
1.60
B
0.36
0.48
C
0.35
0.44
D
4.40
4.60
D1
1.62
1.83
E
2.29
2.60
e
1.50 (TYP.)
e1
3.00 (TYP.)
H
3.94
4.25
B
e
H
e1
D
D1
A
C
L
E
L
0.89
1.20
l
SOT-89 MARKING
Part No.
Marking
AIC431CX
AC01B
TL431CX
AC02B
TL431ACX
AC03B
AIC431/TL431A/TL431
11
l
TO-92 (unit: mm)
SYMBOL
MIN
MAX
A
4.32
5.33
C
0.38 (TYP.)
D
4.40
5.20
E
3.17
4.20
e1
1.27 (TYP.)
A
L
e1
D
C
E
L
12.7
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