AS431
Document number: DS36599 Rev. 4 - 2
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AS431
ADJUSTABLE PRECISION SHUNT REGULATORS
Description
The AS431 is a three-terminal adjustable shunt regulator with
guaranteed thermal stability over a full operation range. It features
sharp turn-on characteristics, low temperature coefficient and low
output impedance, which make it ideal substitute for Zener diode in
applications such as switching power supply, charger and other
adjustable regulators.
The output voltage of AS431 can be set to any value between VREF
(2.5V) and the corresponding maximum cathode voltage (36V).
The AS431 precision reference is offered in two voltage tolerance:
0.5% and 1.0%.
This IC is available in 4 packages: TO92 (Ammo Packing), SOT23,
SOT25 and SOT89.
Features
Programmable Precise Output Voltage from 2.5V to 36V
High Stability under Capacitive Load
Low Temperature Deviation: 4.5mV Typical
Low Equivalent Full-range Temperature Coefficient with
20PPM/°C Typical
Sink Current Capacity from 1mA to 100mA
Low Output Noise
Wide Operating Range of -40 to +125°C
Lead-Free Packages: SOT23, SOT25, TO92 (Ammo Packing),
SOT89
Totally Lead-Free; RoHS Compliant (Notes 1 & 2)
Lead-Free Packages, Available in “Green” Molding Compound:
SOT23, SOT25, TO92 (Ammo Packing), SOT89
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
Applications
Charger
Voltage Adapter
Switching Power Supply
Graphic Card
Precision Voltage Reference
Pin Assignments
(Top View) (Top View)
SOT23 SOT25
Note 4: * Pin 2 is attached to substrate and must be connected to ANODE or
open.
(Top View) (Top View)
SOT89 (Option 1) SOT89 (Option 2)
(Top View)
TO92 (Ammo Packing)
Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS), 2011/65/EU (RoHS 2) & 2015/863/EU (RoHS 3) compliant.
2. See https://www.diodes.com/quality/lead-free/ for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and
Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
ANODE
CATHODEREF
3
21
1 2 3
REF CATHODEANODE
123
REF CATHODEANODE
REF
CATHODE
ANODE1
2
34
5NC
(Note 4)
*
REF
CATHODE
ANODE
1
2
3
AS431
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AS431
Functional Block Diagram
Absolute Maximum Ratings (Note 5)
Symbol
Parameter
Rating
Unit
VKA
Cathode Voltage
40
V
IKA
Cathode Current Range (Continuous)
-100 to 150
mA
IREF
Reference Input Current Range
10
mA
PD
Power Dissipation
Z, R Package
770
mW
N, K Package
370
TJ
Junction Temperature
+150
°C
TSTG
Storage Temperature Range
-65 to +150
°C
ESD
ESD (Human Body Model)
2000
V
Note 5: Stresses greater than 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 Ratings” for extended periods may affect device reliability.
Recommended Operating Conditions
Symbol
Parameter
Min
Max
Unit
VKA
Cathode Voltage
VREF
36
V
IKA
Cathode Current
1.0
100
mA
TA
Operating Ambient Temperature Range
-40
+125
°C
AS431
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AS431
Electrical Characteristics (Operating Conditions: TA = +25°C, unless otherwise specified.)
Symbol
Parameter
Test
Circuit
Conditions
Min
Typ
Max
Unit
VREF
Reference Voltage
0.5%
4
VKA = VREF, IKA = 10mA
2.487
2.500
2.512
V
1.0%
2.475
2.500
2.525
∆VREF
Deviation of Reference Voltage
Over Full Temperature Range
4
VKA = VREF,
IKA = 10mA
0 to +70°C
—
4.5
8
mV
-40 to +85°C
—
4.5
10
-40 to +125°C
—
4.5
16
∆VREF
∆VKA
Ratio of Change in Reference
Voltage to the Change in Cathode
Voltage
5
IKA = 10mA
∆VKA = 10V to VREF
—
-1.0
-2.7
mV/V
∆VKA = 36V to 10V
—
-0.5
-2.0
IREF
Reference Current
5
IKA = 10mA, R1 = 10kΩ, R2 = ∞
—
0.7
4
µA
∆IREF
Deviation of Reference Current
Over Full Temperature Range
5
IKA = 10mA, R1 = 10kΩ, R2 = ∞,
TA = -40 to +125°C
—
0.4
1.2
µA
IKA
(Min)
Minimum Cathode Current for
Regulation
4
VKA = VREF
—
0.4
1.0
mA
IKA
(Off)
Off-state Cathode Current
6
VKA = 36V, VREF = 0
—
0.05
1.0
µA
ZKA
Dynamic Impedance
4
VKA = VREF, IKA = 1 to 100mA,
f ≤ 1.0kHz
—
0.15
0.5
Ω
θJC
Thermal Resistance
—
SOT23
—
135.9
—
°C/W
SOT25
—
135.9
—
TO92 (Ammo Packing)
—
81.9
—
SOT89
—
29.8
—
AS431
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AS431
Performance Characteristics
Reference Voltage vs. Ambient Temperature Reference Current vs. Ambient Temperature
Cathode Current vs. Cathode Voltage Cathode Current vs. Cathode Voltage
Off-State Cathode Current Ratio of Delta Reference Voltage to the
vs. Ambient Temperature Ratio of Delta Cathode Voltage
-60 -40 -20 0 20 40 60 80 100 120 140
2.485
2.490
2.495
2.500
2.505
2.510
Reference Voltage (V)
Ambient Temperature (oC)
VKA = VREF
IKA = 10mA
-60 -40 -20 0 20 40 60 80 100 120 140
0.0
0.5
1.0
1.5
R1=10K,R2=Infinite
IKA=10mA
Reference Current (A)
Ambient Temperature (0C)
-2 -1 0 1 2 3
-100
-50
0
50
100
150
Cathode Current (mA)
Cathode Voltage (V)
VKA=VREF
TA=250C
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5
-200
0
200
400
600
800
Cathode Current (A)
Cathode Voltage (V)
VKA=VREF
TA=250C
-40 -20 0 20 40 60 80 100 120
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Off-State Cathode Current (A)
Ambient Temperature (oC)
VKA=36V
VREF=0
-40 -20 0 20 40 60 80 100 120
-1.4
-1.3
-1.2
-1.1
-1.0
-0.9 VKA=3.5V to 36V
VREF / VKA (mV/V)
Ambient Temperature (oC)
AS431
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AS431
Performance Characteristics (Cont.)
Small Signal Voltage Gain vs. Frequency
Reference Impedance vs. Frequency
Stability Boundary Conditions vs. Load Capacitance
1k 10k 100k 1M
-10
0
10
20
30
40
50
60
70
Voltage Gain (dB)
Small Signal Frequency (Hz)
TA=250C
IKA=10mA
1K 10K 100K 1,000K
0.1
1
10
Reference Impedance ()
Frequency (Hz)
IKA=10mA
TA=25oC
0
10
20
30
40
50
60
70
80
90
100
10
1
0.10.010.001
Stable
Stable
Cathode Current (mA)
Load Capacitance (F)
TA=25oC
VKA=VREF
VKA= 5V:No oscillation
VKA=10V:No oscillation
VKA=15V:No oscillation
AS431
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AS431
Ordering Information
AS431 X X X - X
Packing
Voltage Tolerance
A : 0.5%
Product Name Package
Z : TO92
(Ammo Packing)
N : SOT23
E1/G1
TR : Tape & Reel or
Ammo G1 : RoHS Compliant
and Green
B : 1.0% K : SOT25
R : SOT89
E1 : RoHS Compliant
Part Number
Voltage
Tolerance
Package
(Note 7)
RoHS
Compliant
Lead Free /
Green
Marking ID
Packing
Quantity
Status
(Note 6)
Alternative
AS431ANTR-
E1
0.5%
SOT23
Lead Free
EB5
Tape & Reel
3000
NRND
AS431ANTR
-G1
AS431BNTR-
E1
1.0%
SOT23
Lead Free
EB6
Tape & Reel
3000
NRND
AS431BNTR
-G1
AS431ANTR-
G1
0.5%
SOT23
Green
GB5
Tape & Reel
3000
In
Production
—
AS431BNTR-
G1
1.0%
SOT23
Green
GB6
Tape & Reel
3000
In
Production
—
AS431AKTR-
E1
0.5%
SOT25
Lead Free
E6H
Tape & Reel
3000
NRND
AS431AKTR
-G1
AS431BKTR-
E1
1.0%
SOT25
Lead Free
E6I
Tape & Reel
3000
NRND
AS431BKTR
-G1
AS431AKTR-
G1
0.5%
SOT25
Green
G6H
Tape & Reel
3000
In
Production
—
AS431BKTR-
G1
1.0%
SOT25
Green
G6I
Tape & Reel
3000
In
Production
—
AS431AZ-E1
0.5%
TO92
Lead Free
AS431AZ-
E1
Bulk
1000
End of Life
AS431AZTR
-E1
AS431AZTR-
E1
0.5%
TO92
Lead Free
AS431AZ-
E1
Ammo
2000
In
Production
—
AS431BZ-E1
1.0%
TO92
Lead Free
AS431BZ-
E1
Bulk
1000
End of Life
AS431BZTR
-E1
AS431BZTR-
E1
1.0%
TO92
Lead Free
AS431BZ-
E1
Ammo
2000
In
Production
—
AS431AZ-G1
0.5%
TO92
Green
AS431AZ-
G1
Bulk
1000
End of Life
AS431AZTR
-G1
AS431AZTR-
G1
0.5%
TO92
Green
AS431AZ-
G1
Ammo
2000
In
Production
—
AS431BZ-G1
1.0%
TO92
Green
AS431BZ-
G1
Bulk
1000
End of Life
AS431BZTR
-G1
AS431BZTR-
G1
1.0%
TO92
Green
AS431BZ-
G1
Ammo
2000
In
Production
—
Pb
Lead-Free
Pb
Lead-Free
Pb
Lead-Free
Pb
Lead-Free
Pb
Lead-Free
Pb
Lead-Free
Pb
Lead-Free
Pb
Lead-Free
AS431
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AS431
Ordering Information (Cont.)
Notes: 6. All variants with TO92 package in Bulk packing (AS431AZ-E1, AS431BZ-E1, AS431AZ-G1 and AS431BZ-G1) are End of Life, recommended
alternatives are the variants with the same package in Ammo packing.
NRND: Not Recommended for New Design.
7. For packaging details, go to our website at: https://www.diodes.com/design/support/packaging/diodes-packaging/.
Marking Information
(1) TO92 (Ammo Packing)
(Front View)
Part Number
Voltage
Tolerance
Package
(Note 7)
RoHS
Compliant
Lead Free /
Green
Marking ID
Packing
Quantity
Status
(Note 6)
Alternative
AS431ARTR-
E1
0.5%
SOT89
Lead Free
E43G
Tape & Reel
1000
NRND
AS431ARTR
-G1
AS431BRTR-
E1
1.0%
SOT89
Lead Free
E43H
Tape & Reel
1000
NRND
AS431BRTR
-G1
AS431ARTR-
G1
0.5%
SOT89
Green
G43G
Tape & Reel
1000
In
Production
—
AS431BRTR-
G1
1.0%
SOT89
Green
G43H
Tape & Reel
1000
In
Production
—
First and Second Lines: Logo and Marking ID
(See Ordering Information)
Third Line: Date Code
Y: Year
WW: Work Week of Molding
A: Assembly House Code
XX: Internal Code
AS431
XZ-XX
YWWAXX
Pb
Lead-Free
Pb
Lead-Free
AS431
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AS431
Marking Information (Cont.)
(2) SOT23 (Top View)
(3) SOT89 (Top View)
(4) SOT25
(Top View)
3
21
XXX
: Logo
XXX: Marking ID (See Ordering Information)
First Line: Logo and Marking ID
(See Ordering Information)
Second Line: Date Code
Y: Year
WW: Work Week of Molding
A: Assembly House Code
XX: Internal Code
: Logo
XXX: Marking ID (See Ordering Information)
XXX
2 3
XXXX
YWWAXX
1
XXXX
YWWAXX
23
1
AS431
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AS431
Package Outline Dimensions (All dimensions in mm(inch).)
(1) Package Type: TO92 (Ammo Packing)
4.300(0.169)
4.700(0.185)
12.500(0.492)
14.500(0.571)
2.540(0.100)
Typ
1.270(0.050)
Typ
0. (0.015)
0.550(0.022)
4.400(0.173)
4.800(0.189)
3.430(0.135)
MIN
0.320(0.013)
0.510(0.020)
0.000(0.000)
0.380(0.015)
MAX
1.100(0.043
1.400(0.055)
3.300(0.130)
3.800(0.150)
Φ
1.600(0.063)
)
380
2.500(0.098)
4.000(0.157)
13.000(0.512)
15.000(0.591)
AS431
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AS431
Package Outline Dimensions (Cont. All dimensions in mm(inch).)
(2) Package Type: SOT23
2.300(0.091)
2.500(0.098) 1.200(0.047)
1.400(0.055)
0.890(0.035)
1.030(0.041)
0.300(0.012)
0.510(0.020)
1.900(0.075)REF
2.800(0.110)
3.000(0.118)
2.0°
3.0°
0.500(0.020)
0.700(0.028)
1.050(0.041)REF 0.010(0.0004)
0.100(0.004)
0.900(0.035)
1.100(0.043)
4×R0.100(0.004) 7.0°
7.0°
0.550(0.022)REF
0.200(0.008)MIN
0.100(0.004) GAUGE PLANE
0.080(0.003)
0.180(0.007)
R0.100(0.004)
0.0°
~10.0°
AS431
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AS431
Package Outline Dimensions (Cont. All dimensions in mm(inch).)
(3) Package Type: SOT25
2.820(0.111)
2.650(0.104)
1.500(0.059)
0.000(0.000)
0.300(0.012)
0.950(0.037)
0.900(0.035)
0.100(0.004)
0.200(0.008)
0.300(0.012)
8°
0°
3.100(0.122)
1.700(0.067)
3.000(0.118)
0.500(0.020)
0.150(0.006)
1.300(0.051)
0.200(0.008)
0.600(0.024)
1.800(0.071)
2.000(0.079)
0.700(0.028)
REF
TYP
1.450(0.057)
MAX
AS431
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AS431
Package Outline Dimensions (Cont. All dimensions in mm(inch).)
(4) Package Type: SOT89
45
1.550(0.061)REF
4.400(0.173)
4.600(0.181)
0.900(0.035)
1.200(0.047)
3.950(0.156)
4.250(0.167)
3.000(0.118)
TYP
0.480(0.019)
2.300(0.091)
2.600(0.102)
0.320(0.013)
0.540(0.021)
310
2.060(0.081)REF
1.400(0.055)
1.600(0.063)
0.350(0.014)
0.450(0.018)
R0.150(0.006)
3
10
1.500(0.059)
0.320(0.013)REF
1.620(0.064)REF
2.210(0.087)REF
0.320(0.013)
0.540(0.021)
1.800(0.071)
Option 1 Option 2
0.620(0.024)
1.030(0.041)REF R 0.200(0.008)
1.620(0.064)
1.830(0.072)
2.630(0.104)
2.930(0.115)
Option 1
AS431
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AS431
Suggested Pad Layout
(1) Package Type: SOT23
Y
G
Z
Y
X E
Grid placement courtyard
Dimensions
Z
(mm)/(inch)
G
(mm)/(inch)
X
(mm)/(inch)
Y
(mm)/(inch)
E
(mm)/(inch)
Value
2.900/0.114
1.100/0.043
0.800/0.031
0.900/0.035
0.950/0.037
AS431
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AS431
Suggested Pad Layout (Cont.)
(2) Package Type: SOT25
E2
E1
Y
X
GZ
Dimensions
Z
(mm)/(inch)
G
(mm)/(inch)
X
(mm)/(inch)
Y
(mm)/(inch)
E1
(mm)/(inch)
E2
(mm)/(inch)
Value
3.600/0.142
1.600/0.063
0.700/0.028
1.000/0.039
0.950/0.037
1.900/0.075
AS431
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AS431
Suggested Pad Layout (Cont.)
(3) Package Type: SOT89
X1
X2 Y1
E
X
Y
Z
Dimensi
ons
Z
(mm)/(inch)
X
(mm)/(inch)
X1
(mm)/(inch)
X2
(mm)/(inch)
Y
(mm)/(inch)
Y1
(mm)/(inch)
E
(mm)/(inch)
Value
4.600/0.181
0.550/0.022
1.850/0.073
0.800/0.031
1.300/0.051
1.475/0.058
1.500/0.059
AS431
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AS431
IMPORTANT NOTICE
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes
without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the
application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume
all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated
website, harmless against all damages.
Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and
hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or
indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings
noted herein may also be covered by one or more United States, international or foreign trademarks.
This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.
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Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express
written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and
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use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
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