Diodes AS431I User Manual
AS431I
Document number: DS36816 Rev. 2 - 2
1 of 16
www.diodes.com
January 2014
© Diodes Incorporated
AS431I
A Product Line of
Diodes Incorporated
Description
The AS431I 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 AS431I can be set to any value between V
REF
(2.5V) and the corresponding maximum cathode voltage (36V).
The AS431I is offered in two grade initial voltage tolerance at +25oC,
0.5%, and 1%.
This IC is available in 3 packages: TO-92 (bulk or ammo packing),
SOT-23 and SOT-89.
Features
Programmable Precise Output Voltage from 2.5V to 36V
High Stability Under Capacitive Load
Low Minimum Cathode Current for Regulation: 10µA (Typ.), 50µA
(Max.)
Low Temperature Deviation: 4.5mV Typical
Sink Current Capacity from 50µA to 100mA
Low Output Noise
Wide Operating Range: -40 to +125oC
Applications
Charger
Voltage Adapter
Switching Power Supply
Graphic Card
Precision Voltage Reference
1 2 3
REF ANODE CATHODE
CATHODE
ANODE
REF
3
2
1
1 2
3
REF ANODE CATHODE
LOW CATHODE CURRENT ADJUSTABLE PRECISION SHUNT REGULATOR
Pin Assignments
(Top View) (Top View) (Top View)
(SOT-23/ N Package) (SOT-89 (Option 1/ R Package) (SOT-89 (Option 2/ R Package)
AS431I
Document number: DS36816 Rev. 2 - 2
2 of 16
www.diodes.com
January 2014
© Diodes Incorporated
AS431I
A Product Line of
Diodes Incorporated
1
2
3
CATHODE
ANODE
REF
CATHODE
ANODE
REF
1
2
3
V
OUT
=(1+R1/R2)*V
REF
V
OUT
=(1+R2/R3)*V
REF
Pin Assignments (Cont.)
(Top View) (Top View)
(TO-92 (Bulk Packing)/ Z Package) (TO-92 (Ammo Packing)/ Z Package)
Typical Applications Circuit
Shunt Regulator
High Current Shunt Regulator
AS431I
Document number: DS36816 Rev. 2 - 2
3 of 16
www.diodes.com
January 2014
© Diodes Incorporated
AS431I
A Product Line of
Diodes Incorporated
I
OUT=VREF
/R2+ I
KA
Typical Applications Circuit (Cont.)
Current Source or Current Limit
Precision 5V 1A Regulator
PWM Converter with Reference
AS431I
Document number: DS36816 Rev. 2 - 2
4 of 16
www.diodes.com
January 2014
© Diodes Incorporated
AS431I
A Product Line of
Diodes Incorporated
REF
V
REF
CATHODE
ANODE
+
-
Symbol
Parameter
Rating
Unit
VKA
Cathode Voltage
40
V
I
KA
Cathode Current Range (Continuous)
-100 to 150
mA
I
REF
Reference Input Current Range
10
mA
P
D
Power Dissipation
TO-92
770
mW
SOT-89
770
SOT-23
370
TJ
Junction Temperature
+150
ºC
T
STG
Storage Temperature Range
-65 to +150
ºC
ESD
ESD (Human Body Model)
2000
V
Symbol
Parameter
Min
Max
Unit
V
KA
Cathode Voltage
V
REF
36 V I
KA
Cathode Current
0.05
100
mA
TA
Operating Ambient Temperature Range
-40
+125
ºC
Functional Block Diagram
Absolute Maximum Ratings (Note 1)
Note 1: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stres s 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
AS431I
Document number: DS36816 Rev. 2 - 2
5 of 16
www.diodes.com
January 2014
© Diodes Incorporated
AS431I
A Product Line of
Diodes Incorporated
Symbol
Parameter
Test
Circuit
Conditions
Min
Typ
Max
Unit
V
REF
Reference Voltage
0.5%
4
V
KA
= V
REF
, I
KA
= 10mA
2.487
2.500
2.512
V
1.0%
2.475
2.500
2.525
∆V
REF
Deviation of Reference Voltage
Over Full Temperature Range
4
V
KA
= V
REF
,
I
KA
= 10mA
0 to +70°C
–
4.5
8
mV
-40 to +85°C
–
4.5
10
-40 to +125°C
–
4.5
16
∆V
REF
∆VKA
Ratio of Change in Reference
Voltage to the Change in Cathode
Voltage
5
I
KA
= 10mA
∆V
KA
= 10V to V
REF
–
-1.0
-2.7
mV/V
∆V
KA
= 36V to 10V
–
-0.5
-2.0
I
REF
Reference Current
5
I
KA
= 10mA, R1 = 10KΩ, R2 = ∞
–
0.035
0.5
µA
∆I
REF
Deviation of Reference Current
Over Full Temperature Range
5
I
KA
= 10mA, R1 = 10KΩ, R2 = ∞,
TA = -40 to +125°C
–
0.03
0.3
µA
I
KA
(Min)
Minimum Cathode Current for
Regulation
4
V
KA
= V
REF
–
10
50
µA
I
KA
(Off)
Off-state Cathode Current
6
V
KA
= 36V, V
REF
= 0
–
0.05
1.0
µA
Z
KA
Dynamic Impedance
4
V
KA
= V
REF
, IKA = 1 to 100mA,
f ≤ 1.0KHz
–
0.15
0.5
Ω
θ
JC
Thermal Resistance
–
TO-92 – 68
–
°C/W
SOT-89
–
29
–
SOT-23
–
113
–
Electrical Characteristics (Operating Conditions: T
= +25ºC, unless otherwise specified.)
A
Loading...