A Product Line of
Diodes Incorporated
AN431
ADJUSTABLE PRECISION SHUNT REGULATORS
Description
The AN431 series ICs are three-terminal adjustable shunt regulators
with guaranteed thermal stability over a full operation range. These
ICs feature sharp turn-on characteristics, low temperature coefficient
and low output impedance, which make them ideal substitutes for
Zener diodes in applications such as switching power supply, charger
and other adjustable regulators.
The output voltage of these ICs can be set to any value between V
REF
(2.5V) and the maximum cathode voltage (36V).
The AN431 precision reference is offered in two voltage tolerance:
0.5% and 1.0%.
These ICs are available in SOT-23 package.
Pin Assignments
(Top View)
ANODE
3
1
2
CATHODE
REF
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/
o
C Typical
Low Dynamic Output Resistance: 0.15Ω Typical
Sink Current Capacity from 1mA to 100mA
Low Output Noise
Wide Operating Range of -40 to +125
o
C
Lead-Free Packages: SOT-23
Totally Lead-Free; RoHS Compliant (Notes 1 & 2)
Lead-Free Packages, Available in “Green” Molding Compound:
SOT-23
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
SOT-23
Applications
Charger
Voltage Adapter
Switching Power Supply
Graphic Card
Precision Voltage Reference
Notes:
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com/quality/lead_free.html 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.
Typical Applications Circuit
R3
V
IN
R1
V
REF
R2
V
OUT
AN431
V
OUT
=(1+R1/R2)*V
REF
Shunt Regulator
AN431
Document number: DS37414 Rev. 3 - 2
1 of 13
www.diodes.com
April 2015
© Diodes Incorporated
A Product Line of
Diodes Incorporated
AN431
Absolute Maximum Ratings
(Note 4)
Symbol
V
KA
I
KA
I
REF
P
D
T
J
T
STG
ESD
Cathode Voltage
Cathode Current Range (Continuous)
Reference Input Current Range
Power Dissipation
Junction Temperature
Storage Temperature Range
ESD (Human Body Model)
Parameter
Rating
40
-100 to 150
10
370
+150
-65 to +150
2000
Unit
V
mA
mA
mW
º
C
º
C
V
Note 4:
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
V
KA
I
KA
T
A
Cathode Voltage
Cathode Current
Operating Ambient Temperature Range
Parameter
Min
V
REF
1.0
-40
Max
36
100
+125
Unit
V
mA
º
C
AN431
Document number: DS37414 Rev. 3 - 2
4 of 13
www.diodes.com
April 2015
© Diodes Incorporated
A Product Line of
Diodes Incorporated
AN431
Electrical Characteristics
Symbol
Reference
Voltage
Parameter
0.5%
4
1.0%
0 to +70
o
C
∆V
REF
Deviation of Reference Voltage
Over Full Temperature Range
4
V
KA
=V
REF
,
I
KA
=10mA
-40 to +85
o
C
-40 to +125
o
C
∆V
REF
∆V
KA
I
REF
∆I
REF
I
KA
(Min)
I
KA
(Off)
Z
KA
θ
JC
Ratio of Change in Reference
Voltage to the Change in Cathode
Voltage
Reference Current
Deviation of Reference Current
Over Full Temperature Range
Minimum Cathode
Regulation
Current
for
∆V
KA
=10V to V
REF
5
I
KA
=10mA
∆V
KA
=36V to 10V
5
5
4
6
4
–
I
KA
=10mA, R1=10KΩ, R2=∞
I
KA
=10mA, R1=10KΩ, R2=∞,
T
A
=-40 to +125
o
C
V
KA
=V
REF
V
KA
=36V, V
REF
=0
V
KA
=V
REF
,
f≤1.0kHz
SOT-23
I
KA
=1
to
100mA,
–
–
–
–
–
–
–
-0.5
0.7
0.4
0.4
0.05
0.15
135
-2.0
4
1.2
1.0
1.0
0.5
–
µA
µA
mA
µA
Ω
º
C/W
V
KA
=V
REF
, I
KA
=10mA
2.475
–
–
–
2.500
4.5
4.5
4.5
-1.0
2.525
8
10
16
-2.7
mV/V
mV
(@T
A
=+25º unless otherwise specified.)
C,
Test
Circuit
Conditions
Min
2.487
Typ
2.500
Max
2.512
Unit
V
REF
V
Off-state Cathode Current
Dynamic Impedance
Thermal Resistance
AN431
Document number: DS37414 Rev. 3 - 2
5 of 13
www.diodes.com
April 2015
© Diodes Incorporated
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