AIC431/TL431A/TL431
Adjustable Precision Shunt Regulators
Analog Integrations Corporation 4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC
www.analog.com.tw
DS-431-06 May 31, 01 TEL: 886-3-5772500 FAX: 886-3-5772510 1
n FEATURES
l Unconditionally Stable.
l Precision Reference Voltage.
AIC431 :2.495V ±0.5%
TL431A :2.495V ±1.0%
TL431 :2.495V ±1.6%
l Sink Current Capability: 200mA.
l Minimum Cathode Current for Regulation: 250µA.
l Equivalent Full-Range Temperature Coefficient:
50 ppm/°C.
l Fast Turn-On Response.
l Low Dynamic Output Impedance: 0.08Ω.
l Adjustable Output Voltage.
l Low Output Noise.
l Space Saving SOT-89, SOT-23, TO-92 and SO8
packages.
n TYPICAL APPLICATION CIRCUIT
V
IN
AIC431
+
V
OUT
R1
R2
+
VOUT=(1+R1/R2)VREF
Precision Regulator
n DESCRIPTION
The AIC431/TL431A/TL431 are 3-terminal ad-
justable precision shunt regulators with guar-
anteed temperature stability over the applica-
ble extended commercial temperature range.
The output voltage may be set at any level
greater than 2.495V (VREF) up to 30V merely
by selecting two external resistors that act as
a voltage divider network. These devices have
a typical output impedance of 0.08Ω. Active
output circuitry provides a very sharp turn-on
characteristics, making these devices excel-
lent 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
ORDER NUMBER PIN CONFIGURATION
AIC431 CX
TL431A CX
TL431
CX
PACKAGING TYPE
S: SMALL OUTLINE
U: SOT-23
X: SOT-89
Z: TO-92
AIC431CX
TL431ACX
TL431CX
(SOT-89)
FRONT VIEW
1: VREF
2: ANODE
3: CATHODE
1
2
3
1 2 3
AIC431CZ
TL431ACZ
TL431CZ
(TO-92)
FRONT VIEW
1: VREF
2: ANODE
3: CATHODE
ANODE
REF
ANODE
NC
ANODE
ANODE
NC
CATHOD
1
3
4
2
8
6
5
7
AIC431CS
TL431ACS
TL431CS
(SO-8)
TOP VIEW
AIC431CUN
TL431ACUN
TL431CUN
(SOT-23)
FRONT VIEW
1: CATHODE
2: VREF
3: ANODE
1
3
2
AIC431CUS
TL431ACUS
TL431CUS
(SOT-23)
FRONT VIEW
1: VREF
2: CATHODE
3: ANODE
3
12
n ABSOLUTE MAXIMUM RATINGS
Cathode Voltage ........……………...............……………..………...............................30V
Continuous Cathode Current ...................………….……...................... -10mA ~ 250mA
Reference Input Current Range .......…………........……..........…………………… 10mA
Operating Temperature Range .......………….........……….........……………. -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
VREF
I
REF
IZ
VZ
IL
IN
AIC431 R2
R1
V
REF
I
REF
I
Z
V
Z
IN IL
AIC431
Note: VZ=VREF(1+R1/R2)+IREFxR1
Fig. 1 Test Circuit for VZ=VREF Fig. 2 Test circuit for VZ>VREF
IN
VZ
IZ(OFF)
AIC431
Fig. 3 Test circuit for off-state Current
n ELECTRICAL CHARACTERISTICS (Ta=25°C, unless otherwise specified.)
PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT
VZ=VREF,AIC431 2.482 2.495 2.508
IL =10mA (Fig. 1) TL431A 2.470 2.495 2.520
Reference Voltage
TL431
VREF
2.455 2.495 2.535
V
Deviation of Reference
Input Voltage Over
Temperature (Note 3)
VZ = VREF , IL =10mA,
Ta = 0°C~ +85°C (Fig. 1) VDEV 9.0 20 mV
Ratio of the Change in Refer-
ence Voltage to IZ=10mA ∆VZ=10V-VREF -0.5 -2.0 mV/V
the Change in Cathode volt-
age (Fig. 2) ∆VZ=30V-10V
∆VREF
∆VZ-0.35 -1.5 mV/V
Reference Input Current R1 =10KΩ, R2=∞,
IL =10mA (Fig. 2) IREF 0.8 3.5 µA
AIC431/TL431A/TL431
4
Deviation of Reference Input
Current over Temperature R1 =10KΩ, R2=∞,
IL =10mA
Ta =-20°C ~ +85°C (Fig. 2) αIREF 0.31.2 µA
AIC431/TL431A/TL431
5
n ELECTRICAL CHARACTERISTICS (Continued)
PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT
Minimum Cathode current for
Regulation VZ=VREF (Fig. 1) IZ(MIN) 0.25 0.5 mA
Off-State Current VZ=20V, VREF =0V (Fig. 3) IZ(OFF) 0.1 1.0 µA
Dynamic Output Impedance
(Note 4) VZ=VREF
Frequency= 0Hz (Fig. 1) RZ0.08 0.3 Ω
T2
T1
VMAX
VDEV = VMAX-VMIN
VMIN
TEMPERATURE
Note 3. Deviation of reference input voltage, VDEV, 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, αVREF is defined as:
T1T2
10
C)25 (atVV
T1T2
6
10
C)25 (atVV-V
C
ppm
V
6
REF
DEV
REF
MINMAX
REF −
°
±
=
−
°
±
=
°
∆
Where:
T2−T1=full temperature change.
αVREF can be positive or negative depending on
whether the slope is positive or negative.
Example: VDEV= 9.0mV, VREF= 2495mV,
T2−T1= 70°C, slope is negative.
C50ppm/VC70
6
10
2495mV
9.0mV
REF °−=
=°
α
Note 4. The dynamic output impedance, Rz, is de-
fined as:
RZ = Z
ZV
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
1Rz
Iz
Vz
zr+≅
∆
∆
=
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
IZ(MIN)
VZ =VREF
TA =25°C
Cathode Current vs Cathode Voltage
Cathode Current (µA)
Cathode Voltage (V) -40 -20 0 20 40 60 80 100 120
2.40
2.42
2.44
2.46
2.48
2.50
2.52
2.54
2.56
2.58
Reference Voltage
vs Temperature
VZ =VREF
IZ =10mA
Reference
Voltage (V)
Temperature (
°
C)
VREF=2.535V
VREF=2.495V
VREF=2.455V
AIC431/TL431A/TL431
6
n TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
-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
Reference Input Current
vs Temperature
Reference
Input
Current (
µ
A)
Temperature (
°
C)
R1=10KΩ
R2=∞
IZ=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
VZ=VREF
IZ=1mA to100mA
F <1KHz
Dynamic Impedance vs Temperature
Dynamic
Impedance (
Ω
)
Temperature (
°
C)
0
5
10
15
20
25
30
35
40
-6
-5
-4
-3
-2
-1
0
Change in Reference Voltage
vs Cathode Voltage
Change
in
Reference
Voltage (mV)
Cathode Voltage (V)
IZ =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
Off-State Cathode Current vs Temperature
Off-State Cathode Current (µA)
Temperature (°C)
VREF=0V
VZ=30V
10
100
1k
10k
100k
1M
10M
-10
0
10
20
30
40
50
60
70
80
Av
IZ =10mA
TA=25°C
Small Signal Voltage Amplification vs Frequency
Small Signal Voltage Amplification
Frequency (Hz)
R1
10K R
250
+
VIN
CIN
47
µ
F
V1
AIC431
Output
Test Circuit For Frequency Response
AIC431/TL431A/TL431
7
n TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
Pulse Response
Input
Output
RA
50
RB
220
AIC431
OUTPUT
Pulse
Generator
f=100kHz
Test Circuit For Pulse Respnose
1E-4 1E-3 0.01 0.1 1 10
0
20
40
60
80
100
Stability Boundary Conditions
Cathode Current (mA)
Load Capacitance (µF)
VZ=VREF Stable
Stable
CL
VIN
R
150
AIC431
VZ
The areas between the curves represent condition that Test Circuit for Stability Boundary Conditions
may cause the device oscillate
1
K
10
K
100
K
1M
0.1
1
10
Iz=10mA
TA=25°C
Dynamic impedance vs. Frequency
Dynamic
Impedance (
Ω
)
Frequency
(
Hz
)
R1
50
+
AC 3V
R2
50
AIC431
GND
Output
+
AIC431/TL431A/TL431
8
n SYMBOL n BLOCK DIAGRAM
ANODE (A)
REF (R)
CATHODE (C)
AIC431
ANODE (A)
CATHODE (C)
REF (R)
+
-
2.495V
n APPLICATION EXAMPLES
VIN
R1A
R2A
R1B
R2B AIC431
AIC431
R
ON
OFF C
VIN
+AIC431
LED on when Low Limit<VIN< High Limit
Low Limit ≅ VREF (1+R1B/R2B) Delay=R x C xln ( V
V V
IN
IN REF−)
High Limit ≅ VREF (1+R1A/R2A)
Fig. 4 Voltage Monitor Fig. 5Delay Timer
RCL IOUT
VIN
AIC431 R
VIN
S
IOUT
AIC431
IOUT=VREF/ RCL IOUT=VREF /RS
Fig. 6 Current Limiter or Current Source Fig. 7 Constant-Current Sink
AIC431/TL431A/TL431
9
n APPLICATION EXAMPLES (Continued)
VOUT
R1
R2
VIN
AIC431
VIN R1
R2
VOUT
FUSE
AIC431
VOUT ≅ (1+R1/R2) x VREF VLIMIT ≅ (1+R1/R2) x VREF
Fig 8. Higher-Current Shunt Regulator Fig 9. Crow Bar
R1A
R2A
R2B
R1B
VIN
Output ON when
Low Limit <V
IN
< High Limit
+
VBE
AIC431
AIC431
Low Limit≅ VREF ( 1+ R1B/ R2B )+ VBE
High Limit ≅ VREF ( 1+ R1A/ R2A )
Fig 10. Over-Voltage/Under-Voltage Protection Circuit
AIC431/TL431A/TL431
10
n PHYSICAL DIMENSIONS
l 8 LEAD PLASTIC SO (unit: mm)
SYMBOL MIN MAX
A1.35 1.75
A1 0.10 0.25
B0.33 0.51
C0.19 0.25
D4.80 5.00
E3.80 4.00
e1.27(TYP)
H5.80 6.20
L0.40 1.27
D
H
e
A
B
A1
C
E
L
l SOT-23 (unit: mm)
SYMBOL MIN MAX
A1.00 1.30
A1 —0.10
A2 0.70 0.90
b0.35 0.50
C0.10 0.25
D2.70 3.10
E1.40 1.80
e1.90 (TYP)
H2.60 3.00
L0.37 —
H
A1
A
A2
b
θ1
L
C
D
E
e
θ11°9°
l SOT-23 MARKING
Part No. Marking Part No. Marking
AIC431CUN AC1N AIC431CUS AC1S
TL431CUN AC2N TL431CUS AC2S
TL431ACUN AC3N TL431ACUS AC3S
AIC431/TL431A/TL431
11
n PHYSICAL DIMENSIONS (Continued)
l SOT-89 (unit: mm)
SYMBOL MIN MAX
A1.40 1.60
B0.36 0.48
C0.35 0.44
D4.40 4.60
D1 1.62 1.83
E2.29 2.60
e1.50 (TYP.)
e1 3.00 (TYP.)
H3.94 4.25
B
e
H
e1
D
D1
A
C
L
E
L0.89 1.20
l SOT-89 MARKING
Part No. Marking
AIC431CX AC01B
TL431CX AC02B
TL431ACX AC03B
l TO-92 (unit: mm)
SYMBOL MIN MAX
A4.32 5.33
C0.38 (TYP.)
D4.40 5.20
E3.17 4.20
e1 1.27 (TYP.)
AL
e1
D
C
E
L12.7 -
