Page No. : 1/7
AX431 Series
Adjustable Shunt Regulator
AX431 Series Pin Assignment
3
2
3-Lead Plastic
SOT-23
Package Code: N
Pin 1: Reference
Pin 2: Cathode
Pin 3: Anode
3-Lead Plastic
SOT-89
Package Code: M
Pin 1: Reference
Pin 2: Anode
Pin 3: Cathode
3-Lead Plastic
TO-92
Package Code: A
Pin 1: Reference
Pin 2: Anode
Pin 3: Cathode
Description
The AX431 series are three-terminal adjustable regulators with guarante-
ed thermal stability over applicable temperature ranges. The output
voltage may be set to any value between V
REF
(approximately 2.495 volts)
and 36 volts with two external resistors. These devices have a typical
dynamic output impedance of 0.2Ω. Active output circuitry provides a very
sharp turn-on characteristic, making these devices excellent replacement
for zener diodes in many applications.
1
1
2
3
Features
•
Programmable output voltage
•
Temperature coefficient is 50ppm/
o
C typical
•
Temperature compensated for operation over full temperature range
•
Low output noise voltage
•
Fast turn on response
12
8
•
1
2
3
3
Ordering Information
Package
SOT-23
SOT-89
TO-92
SO-8
V
REF
: 2.495±2%
AX431AN
AX431AM
AX431AA
AX431AS
V
REF
: 2.495±1%
AX431BN
AX431BM
AX431BA
AX431BS
4
3-Lead Plastic
SO-8
Package Code: S
7
6 Pin 1: Cathode
5
Pin 2/3/6/7: Anode
Pin 4/5: NC
Pin 8: Reference
V
REF
: 2.495±0.5%
AX431CN
AX431CM
AX431CA
AX431CS
Absolute Maximum Ratings
(Operating temperature range applies unless otherwise specified)
Characteristics
Cathode Voltage
Cathode Current Range (Continuous)
Reference Input Current Range
Symbol
V
KA
I
K
I
REF
Value
36
-100~+150
0.05~+10
SOT-23
Power Dissipation
P
D
SOT-89
TO-92
SO-8
Operating Temperature Range
Storage Temperature Range
T
opr
T
stg
0~+70
-65~+150
280
770
770
770
o
o
Unit
V
mA
mA
mW
C
C
Operating Conditions
Characteristics
Cathode Voltage
Cathode Current Range (Continuous)
Symbol
V
KA
I
K
Min.
V
REF
1
Max.
36
100
Unit
V
mA
AVANTICS - AX431 Series
Specification No.: 050308-FE0001
Page No. : 2/7
Functional Block Diagram & Symbol
Functional Block Diagram
Symbol
Cathode
Reference
V
REF
+
-
Cathode
Reference
Anode
Anode
Test Circuits
Fig 1. V
K
=V
REF
IN
I
REF
I
K
V
REF
R
2
V
REF
I
I
V
K
Fig 2. V
K
>V
REF
IN
R
1
I
I
V
K
I
REF
I
K
I
OFF
Fig 3. Off-State Current
IN
V
K
Note: V
K
=V
REF
(1+R
1
/R
2
)+I
REF
xR
1
Electrical Characteristics
(T
A
=25
o
C unless otherwise specified)
Characteristics
Reference Input
Voltage
(Fig1)
AX431AN/AM/AA/AS
AX431BN/BM/BA/BS
AX431CN/CM/CA/CS
Symbol
V
REF
V
REF(dev)
∆V
REF
/
∆V
K
I
REF
I
REF(dev)
I
K(min)
I
K(off)
Z
K
Test Conditions
V
K
=V
REF
, I
K
=10mA
V
K
=V
REF
, I
K
=10mA
T
min
≤T
a
≤T
max
I
K
=10mA,
∆V
K
=10V to V
REF
I
K
=10mA,
∆V
K
=36V to 10V
I
K
=10mA, R
1
=10kΩ,
R
2
=∞
I
K
=10mA, R
1
=10kΩ,
R
2
=∞, T
a
=Full Range
V
K
=V
REF
V
K
=36V, V
REF
=0
V
K
=V
REF
, f≤1kHz
I
K
=1 to 100mA
Min
2.445
2.470
2.483
-
-
-
-
-
-
-
-
Typ
2.495
2.495
2.495
4
-1.4
-1.0
2
0.4
0.4
0.1
0.2
Max
2.545
2.520
2.507
17
-2.7
-2.0
4
1.2
1.0
1.0
0.5
Unit
V
mV
mV/V
mV/V
uA
uA
mA
uA
Ω
Deviation of Reference Input Voltage Over-
Temperature
(Fig1)
Ratio of Change in Reference Input Voltage
to the Change in Cathode Voltage
(Fig2)
Reference Input Current
(Fig2)
Deviation of Reference Input Current Over
Full Temperature Range
(Fig2)
Minimum Cathode Current for Regulation
(Fig1)
Off-State Cathode Current
(Fig3)
Dynamic Output Impedance
(Fig1)
AVANTICS - AX431 Series
Specification No.: 050308-FE0001
Page No. : 3/7
Characteristics Curve
Cathode Current & Cathode Voltage
150
125
Change in Reference Input Voltage (mV)
100
Cathode Current (mA)
75
50
25
0
-25
-50
-75
-100
-2
-1
0
1
Cathode Voltage (V)
2
3
V
K
=V
REF
, Ta=25 C
Test Circuit (Fig1)
o
Change in Reference Input Voltage
& Cathode Voltage
5
0
-5
-10
-15
-20
-25
-30
-35
-40
0
10
20
30
Cathode Voltage (V)
40
50
I
K
=10mA, Ta=25 C
Test Circuits (Fig2)
o
Reference Input Voltage & Temperature
2.58
2.56
Reference Input Voltage (V)
2.54
2.52
2.50
2.48
2.46
2.44
2.42
2.40
-40
-20
0
20
40
o
Cathode Current & Cathode Voltage
1000
800
600
400
200
0
-200
-400
-2
-1
0
1
Cathode Voltage (V)
2
3
o
V
K
=V
REF
, I
K
=10mA
Test Circuit (Fig1)
60
80
100
120
Cathode Current (uA)
V
K
=V
REF
, Ta=25 C
Test Circuit (Fig1)
Temperature ( C)
Small Signal Voltage Amplification &
Frequency
60
50
Voltage Amplification (dB)
40
30
Vout
20
10
0
-10
1000
+
10uF
15K
Ik
240
8.2K
GND
10000
100000
Frequency (Hz)
1000000
10000000
AVANTICS - AX431 Series
Specification No.: 050308-FE0001
Page No. : 4/7
Typical Application
Fig 4. Shunt Regulator
Fig 5. High Current Shunt Regulator
Vcc
R1
Vout
Vcc
R1
Vout
R2
R2
Vout=(1+R
1
/R
2
)V
REF
Vout=(1+R
1
/R
2
)V
REF
Fig 6. Output Control of a Three-Terminal Fixed
Regulator
Fig 7. Series Pass Regulator
Vcc
IN
AX7805
Vcc
Vout
R1
Vout
R1
OUT
COMMON
R2
R2
Vout=(1+R
1
/R
2
)V
REF
; V
out(min)
=V
REF
+5V
Vout=(1+R
1
/R
2
)V
REF
; V
out(min)
=V
REF
+V
BE
Fig 8. Current Limiter or Current Source
Fig 9. Constant Current Sink
Vcc
Vcc
RCL
Iout
Isink
Rs
Iout=V
REF
/R
CL
AVANTICS - AX431 Series
Isink=V
REF
/R
S
Specification No.: 050308-FE0001
Page No. : 5/7
SOT-23 Dimension
Marking:
DIM
A
B
C
D
G
H
J
K
L
S
V
Min.
2.80
1.20
0.89
0.30
1.70
0.013
0.085
0.32
0.85
2.10
0.25
Max.
3.04
1.60
1.30
0.50
2.30
0.10
0.177
0.67
1.15
2.75
0.65
A
L
4 3 1
B S
Pb Free Mark
Pb-Free: " "
(Note)
Normal: None
3
1
2
Note: Pb-free product can distinguish by the green
label or the extra description on the right
side of the label.
Pin Style: 1.Reference 2.Cathode 3.Anode
Material:
•
Lead solder plating: Sn60/Pb40 (Normal),
Sn/3.0Ag/0.5Cu or Pure-Tin (Pb-free)
•
Mold Compound: Epoxy resin family,
flammability solid burning class: UL94V-0
V
G
*: Typical, Unit: mm
C
D
H
K
J
3-Lead SOT-23 Plastic
Surface Mounted Package
AVANTICS Package Code: N
SOT-89 Dimension
C
H
Marking:
Date Code
AX4 3 1
Control Code
Pb Free Mark
Pb-Free: "
.
"
(Note)
Normal: None
B
D
1
E
G
A
2
3
I
Note: Green label is used for pb-free packing
Pin Style: 1.Reference 2.Anode 3.Cathode
Material:
•
Lead solder plating: Sn60/Pb40 (Normal),
Sn/3.0Ag/0.5Cu or Pure-Tin (Pb-free)
•
Mold Compound: Epoxy resin family,
flammability solid burning class: UL94V-0
F
J
DIM
A
B
C
D
E
F
G
H
I
Min.
4.40
4.05
1.50
2.40
0.36
*1.50
*3.00
1.40
0.35
Max.
4.60
4.25
1.70
2.60
0.51
-
-
1.60
0.41
*: Typical, Unit: mm
3-Lead SOT-89 Plastic
Surface Mounted Package
AVANTICS Package Code: M
AVANTICS - AX431 Series
Specification No.: 050308-FE0001
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