Rev. 4/5/01
SPX431A,B,C Precision Adjustable Shunt Regulator
Copyright 2001 Sipex Corporation
1
SPX431A,B,C
Precision Adjustable Shunt Regulator
FEATURES
APPLICATIONS
Trimmed Bandgap to 0.5%, 1% and 2%
Battery Operating Equipments
Wide Operating Current........................ 1mA to 150mA
Adjustable Supplies
Extended Temperature Range.................... 0
C to 105
C
Switching Power Supplies
Low Temperature Coefficient .......................30 ppm/
C
Error Amplifiers
Offered in TO-92, SOIC, SOT-89, SOT-23-5
Single Supply Amplifier
Improved Replacement in Performance for TL431
Monitors / VCR / TV
Low Cost Solution
Personal Computers
PRODUCT DESCRIPTION
The SPX431 is a 3-terminal adjustable shunt voltage regulator providing a highly accurate bandgap reference. The SPX431 acts as an
open-loop error amplifier with a 2.5V temperature compensation reference. The SPX431s thermal stability, wide operating current
(150mA) and temperature range (0
C to 105
C) makes it suitable for a variety of applications that require a low cost, high performance
solution. SPX431A tolerance of 0.5% is proven to be sufficient to overcome all of the other errors in the system to virtually eliminate
the need for trimming in the power supply manufactures assembly line and contribute a significant cost savings.
The output voltage may be adjusted to any value between V
REF
and 36 volts with two external resistors. The SPX431 is available in
TO-92, SOIC-8, SOT-89, and SOT-23-5 packages.
Anode (A)
Cathode (K)
2.5V
Reference
(R)
+
-
Figure 1. Block Diagram
Rev. 4/5/01
SPX431A,B,C Precision Adjustable Shunt Regulator
Copyright 2001 Sipex Corporation
2
SPX431A,B,C
ABSOLUTE MAXIMUM RATINGS
PARAMETER
SYMBOL
RATING
UNITS
Cathode-Anode Reverse Breakdown
V
KA
37
V
Anode-Cathode Forward Current, (< 10ms)
I
AK
1
A
Operating Cathode Current
I
KA
150
mA
Reference Input Current
I
REF
10
mA
Continuous Power Dissipation at 25
C
TO-92
SOT-23
SOIC-8
SOT-89
P
D
775
200
750
1000
mW
mW
mW
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 sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect reliability.
RECOMMENDED CONDITIONS TYPICAL THERMAL RESISTANCES
PARAMETER
SYMBOL
RATING
UNIT
PACKAGE
0
JA
0
JC
TYPICAL DERATING
Cathode Voltage
V
KA
V
REF
to 20
V
TO-92
160
C/W
80
C/W
6.3 mW/
C
Cathode Current
I
K
10
mA
SOT-23
575
C/W
150
C/W
1.7 mW/
C
SOIC-8
175
C/W
45
C/W
5.7 mW/
C
SOT-89
110
C/W
8
C/W
9.1 mW/
C
Typical deratings of the thermal resistances are given for ambient temperature >25
C.
Rev. 4/5/01
SPX431A,B,C Precision Adjustable Shunt Regulator
Copyright 2001 Sipex Corporation
3
SPX431A,B,C
ELECTRICAL CHARACTERISTICS
at 25
C I
K
@ 10mA V
K
= V
REF
,
unless otherwise specified.
Parameter
Symbol
Test Conditions
Test
Circuit
SPX431A
SPX431B
SPX431C
Unit
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
Reference Voltage
V
REF
T
J
= 0
C to 105
C
1
1
2.490
2.469
2.503
2.515
2.536
2.470
2.449
2.495
2.520
2.541
2.445
2.495
2.545
V
V
V
REF
with Temp.
TC
1
0.07
0.20
0.07
0.20
0.07
0.20
mV/
C
Ratio of Change in
V
REF
to Cathode
Voltage
V
REF
V
K
V
REF
to 10V
10V to 36V
2
-2.7
-2
-1.0
-0.4
0.3
-2.7
-2.0
-1.0
-0.4
0.3
-2.7
-2
-1.0
-0.4
0.3
mV/V
Reference Input
Current
I
REF
2
0.7
4
0.7
4
0.7
4
A
I
REF
Temp Deviation
I
REF
T
J
= 0
C to 105
C
2
0.4
1.2
0.4
1.2
0.4
1.2
A
Min I
K
for
Regulation
I
K(MIN)
1
0.4
1
0.4
1
0.4
1
mA
Off State Leakage
I
K(OFF)
V
REF
= 0V,
V
KA
= 36V
3
0.04
250
0.04
500
0.04
1000
nA
Dynamic Output
Impedance
Z
K A
f
Z
= 1kHz
I
K
= 1 to 150mA
1
0.15
0.5
0.15
0.5
0.15
0.5
Operating Temperature Range (T
J
) = -40
C to 125
C
*see appropriate test circuit (Figure 3)
*CALCULATING AVERAGE TEMPERATURE COEFFICIENT (TC)
Figure 2. V
REF
vs. Temperature
T
V
REF
0
15
30
45
60
75
90
105
-10
0.5
5000
0
0
0
0.07 mV/
C
0.003 %/
C
27 ppm/
C
TC in mV/
C =
TC in % /
C =
V
REF
(mV)
T
A
T
A
V
REF
at 25
C
V
REF
x 100
(
)
TC in ppm/
C =
T
A
V
REF
at 25
C
V
REF
x 10
6
(
)
ppm/
C
%/
C
mV/
C
Rev. 4/5/01
SPX431A,B,C Precision Adjustable Shunt Regulator
Copyright 2001 Sipex Corporation
4
SPX431A,B,C
TEST CIRCUITS
V
IN
V
KA
= V
REF
I
REF
I
K
V
IN
V
KA
I
REF
I
K
R1
R2
(V
REF
)
V
IN
V
KA
I
K(OFF)
Figure 3a. Test Circuit for V
KA
= V
REF
Figure 3b. Test Circuit for V
KA
> V
REF
Figure 3c. Test Circuit for I
KOFF
TYPICAL PERFORMANCE CHARACTERISTICS
-2
-1
0
1
2
3
-100
-75
-50
-25
0
25
50
75
100
125
150
I
K
- Cathode Current (mA)
V
KA
- Cathode Voltage (V)
V
KA
= V
REF
Temperature Range: 0
C to 105
C
V
REF
- Reference Voltage (V)
T
A
- Ambient Temperature (
C)
90
120
-60
-30
0
30
60
2.45
2.46
2.47
2.48
2.49
2.50
2.51
2.52
2.53
V
KA
= V
REF
I
K
= 10mA
900
800
700
600
500
400
300
200
100
0
-100
-200
1.0
-1.0
2.0
0
3.0
=
105
C
25
C
-0
C
V
KA
= V
REF
Temperature Range: 0
C to 105
C
V
KA
- Cathode Voltage (V)
I
K
- Cathode Current (
A)
Figure 4. High Current Operating
Figure 5. Reference Voltage vs. Ambient
Figure 6. Low Current Operating
Characteristics
Temperature
Characteristics
Rev. 4/5/01
SPX431A,B,C Precision Adjustable Shunt Regulator
Copyright 2001 Sipex Corporation
5
SPX431A,B,C
TYPICAL PERFORMANCE CHARACTERISTICS
30
0
-10
-20
-30
-40
-50
0
3
6
9
12
15
18
21
24
27
125
C
75
C
25
C
0
C
-60
-30
0
30
60
90
120
0
0.5
1.0
1.5
2.0
2.5
3.0
I
REF
- Reference Input Current (
A)
T
A
- Ambient Temperature (
C)
V
REF
(mV)
V
KA
- Cathode Voltage (V)
R1 = 10k
R2 =
I
K
= 10mA
I
KA
= 10mA
Figure 7. Reference Input Current vs. Ambient
Figure 8. Reference Voltage Line Regulation vs. Cathode
Temperature
Voltage and T
AMBIENT
20
10
10
100
1 k
10 k
100 k
0
70
30
40
50
60
-60
-30
0
30
60
90
120
0.0
0.025
0.050
0.075
0.100
0.125
0.150
Noise Voltage nV/
Hz
f - Frequency (Hz)
Z
KA
Dynamic Impedance (
)
T
A
- Free Air Temperature
V
KA
= V
REF
I
K
= 10mA
T
A
= 25
C
V
KA
= V
REF
I
KA
= 1 to 100mA
f
1kHz
Figure 9. Noise Voltage vs. Frequency
Figure 10. Low Frequency Dynamic Output Impedance
vs. T
AMBIENT
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