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AS432
1.24V Precision Adjustable Shunt Reference
SEMICONDUCTOR
Features
Temperature-compensated: 50 ppm/C
0.25% to 2.0% bandgap offered
Internal amplifier with 150 mA capability
Multiple temperature ranges
Low frequency dynamic output
impedance: < 150 m
Low output noise
Description
The AS432 is a three terminal adjustable shunt regulator utilizing an
accurate 1.24V bandgap reference. The AS432 is functionally similar to
an AS431 except for its lower reference voltage, making it usable in a
wide variety of low voltage applications.
Because of its robust bipolar technology, the AS432 handles a wide
range of current, and holds off more than 18V so its use is not limited to
low power, low voltage systems. Significant care has been taken to pro-
vide adequate AC bandwidth to allow the AS432 as an amplifier in con-
trol systems and power electronics.
Pin Configuration --
Top view
Ordering Information
CATHODE
TO-92 (LP)
8L SOIC (8D)
ANODE
REFERENCE
REFERENCE
ANODE
ANODE
N/C
CATHODE
ANODE
ANODE
N/C
SOT-89 (S)
CATHODE
ANODE
REFERENCE
1
2
3
4
8
7
6
5
5L SOT-23 (5VS)
ANODE
REFERENCE
N/C
N/C
CATHODE
3L SOT-23 (3VS)
CATHODE
REFERENCE
ANODE
Circuit Type:
1.24V Precision Adjustable
Shunt Regulator
Bandgap Tolerance:
A =
0.25%
C =
0.5%
D =
1.0%
E =
2.0%
Temperature Range:
A = 0
C to 70
C
B = 0
C to 105
C
C = 40
C to 85
C
F = 55
C to 125
C
Packaging Option:
A
B
T
M
N
Package Style:
8D
5VS
3VS
S
LP
= Ammo Pack
= Bulk
= Tube
= Tape and Reel (7" Reel Dia, SOT-23 Only)
= Tape and Reel (13" Reel Dia)
= 8 Pin, Plastic SOIC
= 5 Pin, SOT-23
= 3 Pin, SOT-23
= SOT-89
= TO-92
AS432 A C 8D N
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AS432
1.24V Precision Adjustable Shunt Reference
Functional Block Diagram
+
REFERENCE
(R)
ANODE (A)
CATHODE (K)
1.24 V
+
Absolute Maximum Ratings
Parameter
Symbol
Rating
Units
Cathode-Anode Reverse Breakdown
V
KA
18
V
Anode-Cathode Forward Current
I
AK
1
A
Operating Cathode Current
I
KA
100
mA
Reference Input Current
I
REF
1
mA
Continuous Power at 25C
P
D
TO-92
775
mW
8L SOIC
750
mW
SOT-89
1000
mW
SOT-23/3L/5L
200
mW
Junction Temperature
T
J
150
C
Storage Temperature
T
STG
65 to 150
C
Lead Temperature (Soldering 10 sec.)
T
L
300
C
Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a
stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sec-
tions of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability.
Recommended Conditions
Parameter
Symbol
Rating
Unit
Cathode Voltage
V
KA
V
REF
to 18
V
Cathode Current
I
K
10
mA
Typical Thermal Resistances
Package
JA
JC
Typical Derating
TO-92
160C/W
80C/W
6.3 mW/C
SOIC
175C/W
45C/W
5.7 mW/C
SOT-89
110C/W
8C/W
9.1 mW/C
SOT-23/5L
575C/W
150C/W
1.7 mW/C
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AS432
1.24V Precision Adjustable Shunt Reference
R
1
R
2
I
K
V
IN
V
KA
(V
REF
)
I
REF
I
REF
I
K
V
IN
V
KA
=
V
REF
I
K (OFF)
V
IN
V
KA
0
5
10
0.2
2000
0
0
0
15
0.021 mV/
C
0.008%/
C
8.0 ppm/
C
30
45
60
75
90
105
ppm
mV
%
V
REF
T
Temperature (
C)
TC in mV/
C =
TC in %/
C =
T
A
T
A
X 100
V
REF
(mV)
V
REF
at 25
C
V
REF
TC in ppm/
C =
T
A
X 10
6
V
REF
at 25
C
V
REF
Figure 1a. Test Circuit 1
Figure 1b. Test Circuit 2
Figure 1c. Test Circuit 3
Test Circuits
Typical Performance Curves
* Calculating Average Temperature Coefficient (TC)
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AS432
1.24V Precision Adjustable Shunt Reference
V
KA
Cathode Voltage (V)
I
K
Cathode Current (
A)
0.5
0
0.5
1.0
1.5
200
100
0
100
200
300
400
500
600
700
800
900
Low Current Operating Characteristics
55
C
25
C
125
C
I
K
Cathode Current (mA)
V
KA
Cathode Voltage (V)
2
1
0
1
2
100
75
50
25
0
25
50
75
100
125
150
175
High Current Operating Characteristics
V
KA
= V
REF
Temperature Range 55 to 125
C
60
30
0
30
T
A
Ambient Temperature (
C)
60
90
120
I
Z
off Off State Cathode Current (nA)
100
10
1
0.1
0.01
Off State Leakage
V
KA
= 15 V
V
REF
= 0 V
60
30
0
30
T
A
Ambient Temperature (
C)
60
90
120
V
REF
Reference V
oltage (V)
1.27
1.26
1.25
1.24
1.23
1.22
1.21
1.20
1.19
Reference Voltage vs Ambient Temperature
V
KA
= V
REF
I
K
= 10 mA
V
REF
= 1.240 V at 25
C
Figure 4
Figure 5
Figure 2
Figure 3
Typical Performance Curves
30
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AS432
1.24V Precision Adjustable Shunt Reference
60
30
0
30
T
A
Ambient Temperature (
C)
60
90
120
I
REF
Reference Input Current (
A)
2.4
2.3
2.2
2.1
2.0
Reference Input Current
R1 = 10 k
R2 =
I
K
= 10 mA
0
3
6
9
12
15
18
40
C
25
C
75
C
125
C
V
KA
Cathode Voltage (V)
V
REF
Change in Reference V
oltage (mV)
0
10
20
30
40
50
Reference Voltage Line Regulation
I
K
= 10 mA
Temperature Range: 55 to 125
C
10
100
1 k
10 k
100 k
f Frequency (Hz)
70
60
50
40
30
20
10
0
Noise V
oltage nV/
Hz
Noise Voltage
V
KA
= V
REF
I
K
= 10 mA
T
A
= 25
C
60
30
0
30
T
A
Free Air Temperature (
C)
60
90
120
40
30
20
10
0
Z
KA
Dynamic Impedance (m
)
Low Frequency Dynamic Output Impedance
V
KA
= V
REF
V
KA
= 1 to 100 mA
f
1kHz
Typical Performance Curves
Figure 6
Figure 7
Figure 8
Figure 9
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