SEMICONDUCTOR
AS432
1.24V Precision Adjustable Shunt Reference/Amplifier
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 cur-
rent, and holds off more than 18V so its use is not limited to low power, low volt-
age systems. Significant care has been taken to provide adequate AC bandwidth
to allow the AS432 as an amplifier in control systems and power electronics.
Features
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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 m½
Low output noise
Pin Configuration Ñ
Top view
TO-92 (LP)
CATHODE
CATHODE
ANODE
ANODE
REFERENCE
ANODE
N/C
2
3
4
1
SOIC (D)
8
7
6
5
REFERENCE
ANODE
ANODE
N/C
SOT-23/5L (DBV)
N/C
N/C
CATHODE
REFERENCE
ANODE
SOT-89 (S)
CATHODE
ANODE
REFERENCE
ANODE
SOT-23/3L (VS)
CATHODE
REFERENCE
Ordering Information
AS432 A 2 D 7
Circuit Type:
1.24V Precision Adjustable
Shunt Regulator/Amplifier
Temperature Range:
A = 0°C to 70°C
B = 0°C to 105°C
C = –40°C to +85°C
Bandgap Tolerance:
=
±2%
2
=
±1%
1
R5 =
±0.5%
R25 =
±0.25%
Packaging Option:
A = Ammo Pack
B = Bulk
T = Tube
7 = Tape and Reel (7" Reel Dia)
13 = Tape and Reel (13" Reel Dia)
Package Style:
= SOIC
D
DBV = SOT-23/5L
LP = TO-92
= SOT-89
S
VS = SOT-23/3L
ASTEC Semiconductor
1
AS432
1.24V Precision Adjustable Shunt Reference/Amplifier
Functional Block Diagram
CATHODE (K)
REFERENCE
(R)
+
Ð
+
Ð
1.24 V
ANODE (A)
Absolute Maximum Ratings
Parameter
Cathode-Anode Reverse Breakdown
Anode-Cathode Forward Current
Operating Cathode Current
Reference Input Current
Continuous Power at 25¡C
TO-92
8L SOIC
SOT-89
SOT-23/3L/5L
Junction Temperature
Storage Temperature
Lead Temperature (Soldering 10 sec.)
T
J
T
STG
T
L
Symbol
V
KA
I
AK
I
KA
I
REF
P
D
775
750
1000
200
150
Ð65 to 150
300
mW
mW
mW
mW
¡C
¡C
¡C
Rating
18
1
100
1
Units
V
A
mA
mA
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
Cathode Voltage
Cathode Current
Symbol
V
KA
I
K
Rating
V
REF
to 18
10
Unit
V
mA
Typical Thermal Resistances
Package
TO-92
SOIC
SOT-89
SOT-23/3L/5L
θ
JA
160¡C/W
175¡C/W
110¡C/W
575¡C/W
θ
JC
80¡C/W
45¡C/W
8¡C/W
150¡C/W
Typical Derating
6.3 mW/¡C
5.7 mW/¡C
9.1 mW/¡C
1.7 mW/¡C
ASTEC Semiconductor
2
1.24V Precision Adjustable Shunt Reference/Amplifier
Electrical Characteristics
AS432
Electrical characteristics are guaranteed over the full junction temperature range (0Ð105¡C). Ambient temperature must be derated
based upon power dissipation and package thermal characteristics. Unless otherwise stated, test conditions are: V
KA
= V
REF
and
I
K
= 10 mA.
Test
Condition
I
K
= 10 mA
T
J
= 25¡C
V
K
= V
REF
V
KA
= 1.25 to 15 V
I
K
= 1 to 100 mA
0 < T
J
< 105¡C
0 < T
J
< 105¡C
AS432 (0.25%)
Min.
Typ. Max.
1.237
1.240
1.243
AS432 (0.5%)
Min.
Typ. Max.
1.234
1.240
1.246
Parameter
Output Voltage
Symbol
V
REF
Unit
V
Line Regulation
Load Regulation
Temperature Deviation
Reference Input Current
Reference Input Current
Temperature Coefficient
Minimum Cathode
Current for Regulation
Off State Leakage
ÆV
REF
ÆV
REF
ÆV
REF
I
REF
ÆI
REF
I
K(min)
I
K(min)
28
3.9
5
2.3
0.14
0.2
50
6
10
6
0.6
1
500
28
3.9
5
2.3
0.14
0.2
0.04
50
6
10
6
0.6
1
500
mV
mV
mV
µA
µA
mA
nA
V
REF
= 0 V,
V
KA
= 15 V
0.04
Parameter
Output Voltage
Symbol
V
REF
Test
Condition
I
K
= 10 mA
T
J
= 25¡C
V
K
= V
REF
V
KA
= 1.25 to 15 V
I
K
= 1 to 100 mA
0 < T
J
< 105¡C
0 < T
J
< 105¡C
AS432 (1.0%)
Min.
Typ. Max.
1.228
1.240
1.252
AS432 (2.0%)
Min.
Typ. Max.
1.215
1.240
1.256
Unit
V
Line Regulation
Load Regulation
Temperature Deviation
Reference Input Current
Reference Input Current
Temperature Coefficient
Minimum Cathode
Current for Regulation
Off State Leakage
ÆV
REF
ÆV
REF
ÆV
REF
I
REF
ÆI
REF
I
K(min)
I
K(min)
28
3.9
5
2.3
0.14
0.2
50
6
12
6
0.6
1
500
28
3.9
5
2.3
0.14
0.2
0.04
50
6
12
6
0.6
1
500
mV
mV
mV
µA
µA
mA
nA
V
REF
= 0 V,
V
KA
= 15 V
0.04
*Temperature deviation is defined as the maximum deviation of the reference over the given temperature range and does not imply
an incremental deviation at any given temperature.
ASTEC Semiconductor
3
AS432
1.24V Precision Adjustable Shunt Reference/Amplifier
Typical Performance Curves
*Calculating Average Temperature Coefficient (TC)
ppm
mV
∆V
REF
(mV)
∆T
A
∆V
REF
2000
0.2
–5
• TC in %/°C =
V
REF
at 25°C
∆T
A
∆V
REF
–10
0
15
30
45 60 75
Temperature (°C)
90
105
• TC in ppm/°C =
V
REF
at 25°C
∆T
A
%
0
0
∆T
∆V
REF
0
• TC in mV/°C =
X 100
X 10
6
0.021 mV/°C
0.008%/°C
8.0 ppm/°C
Test Circuits
V
IN
V
KA
= V
REF
V
IN
V
KA
V
IN
V
KA
I
REF
I
K
I
K
R
1
I
REF
(V
REF
)
R
2
I
K (OFF)
Figure 1a. Test Circuit 1
Figure 1b. Test Circuit 2
Figure 1c. Test Circuit 3
ASTEC Semiconductor
4
1.24V Precision Adjustable Shunt Reference/Amplifier
Typical Performance
AS432
Low Current Operating Characteristics
900
800
700
I
K
– Cathode Current (mA)
I
K
– Cathode Current (µA)
600
500
400
300
200
100
0
–55°C
–100
–200
–0.5
0
0.5
V
KA
– Cathode Voltage (V)
1.0
25°C
1.5
–75
–100
–2
125°C
175
150
125
100
75
50
25
0
–25
–50
High Current Operating Characteristics
V
KA
= V
REF
Temperature Range –55 to 125°C
–1
0
V
KA
– Cathode Voltage (V)
1
2
Figure 2
Figure 3
Off State Leakage
100
V
KA
= 15 V
V
REF
= 0 V
I
Z
off – Off State Cathode Current (nA)
V
REF
– Reference Voltage (V)
10
1.27
1.26
1.25
1.24
Reference Voltage vs Ambient Temperature
V
KA
= V
REF
I
K
= 10 mA
V
REF
= 1.240 V at 25°C
1.23
1.22
1.21
1.20
1
0.1
0.01
–60
–30
0
30
60
90
120
1.19
–60
–30
0
30
60
90
120
T
A
– Ambient Temperature (°C)
T
A
– Ambient Temperature (°C)
Figure 4
Figure 5
ASTEC Semiconductor
5
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