A Product Line of
Diodes Incorporated
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: TO-92 (bulk or ammo packing),
SOT-23, SOT-23-5 and SOT-89.
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: SOT-23, SOT-23-5, TO-92, SOT-89
Totally Lead-Free; RoHS Compliant (Notes 1 & 2)
Lead-Free Packages, Available in “Green” Molding Compound:
SOT-23, SOT-23-5, TO-92, SOT-89
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
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.
Notes:
Pin Assignments
N Package
(SOT-23)
R Package
(SOT-89 Option 1)
R Package
(SOT-89 Option 2)
1
REF
2
3
1
REF
2
3
ANODE CATHODE
ANODE CATHODE
K Package
(SOT-23-5)
Z Package
(TO-92 (Bulk Packing))
Z Package
(TO-92 (Ammo Packing
))
3
CATHODE
2
ANODE
1
REF
Note:
4. * Pin 2 is attached to substrate and must be connected to ANODE or open.
AS431
Document number: DS36599 Rev. 3 - 2
1 of 19
www.diodes.com
October 2013
© Diodes Incorporated
A Product Line of
Diodes Incorporated
AS431
Functional Block Diagram
Absolute Maximum Ratings
(Note 5)
Symbol
V
KA
I
KA
I
REF
P
D
T
J
T
STG
ESD
Note 5:
Parameter
Cathode Voltage
Cathode Current Range (Continuous)
Reference Input Current Range
Power Dissipation
Junction Temperature
Storage Temperature Range
ESD (Human Body Model)
Rating
40
-100 to 150
10
Z, R Package
N, K Package
+150
-65 to +150
2000
770
370
Unit
V
mA
mA
mW
°C
°C
V
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
Parameter
Cathode Voltage
Cathode Current
Operating Ambient Temperature Range
Min
V
REF
1.0
-40
Max
36
100
+125
Unit
V
mA
°C
AS431
Document number: DS36599 Rev. 3 - 2
4 of 19
www.diodes.com
October 2013
© Diodes Incorporated
A Product Line of
Diodes Incorporated
AS431
Electrical Characteristics
(Operating Conditions: T
A
= +25°C, unless otherwise specified.)
Symbol
V
REF
Parameter
Reference Voltage
0.5%
1.0%
Test
Circuit
4
Conditions
V
KA
= V
REF
, I
KA
= 10mA
0 to +70°C
-40 to +85°C
-40 to +125°C
∆V
KA
= 10V to V
REF
∆V
KA
= 36V to 10V
Min
2.487
2.475
–
–
–
–
–
–
–
–
–
–
–
–
–
–
Typ
2.500
2.500
4.5
4.5
4.5
-1.0
-0.5
0.7
0.4
0.4
0.05
0.15
135.9
135.9
81.9
29.8
Max
2.512
2.525
8
10
16
-2.7
-2.0
4
1.2
1.0
1.0
0.5
–
–
–
–
°C/W
mV/V
µA
µA
mA
µA
Ω
mV
Unit
V
∆V
REF
Deviation of Reference Voltage
Over Full Temperature Range
Ratio of Change in Reference
Voltage to the Change in Cathode
Voltage
Reference Current
Deviation of Reference Current
Over Full Temperature Range
Minimum Cathode Current for
Regulation
Off-state Cathode Current
Dynamic Impedance
4
V
KA
= V
REF
,
I
KA
= 10mA
∆V
REF
∆V
KA
I
REF
∆I
REF
I
KA
(Min)
I
KA
(Off)
Z
KA
5
5
5
4
6
4
I
KA
= 10mA
I
KA
= 10mA, R1 = 10KΩ, R2 =
∞
I
KA
= 10mA, R1 = 10KΩ, R2 =
∞
,
T
A
= -40 to +125°C
V
KA
= V
REF
V
KA
= 36V, V
REF
= 0
V
KA
= V
REF
, I
KA
= 1 to 100mA,
f
≤
1.0KHz
SOT-23
SOT-23-5
TO-92
SOT-89
θ
JC
Thermal Resistance
–
AS431
Document number: DS36599 Rev. 3 - 2
5 of 19
www.diodes.com
October 2013
© Diodes Incorporated
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