1
Rev. 8/8/02 SPX431L Precision Adjustable Shunt Regulator
Copyright 2002 Sipex Corporation
Precision Adjustable Shunt Regulator
SPX431L
DESCRIPTION
FEATURES
Tight Voltage Tolerance 0.5% at 10mA
Wide Operating Current 1mA to 100mA
Extended Temperature Range:
0
C to 105
C
Low Temperature Coefficient 30 ppm/
C
Offered in TO-92, SOIC, SOT-89,
SOT-23-3
Improved Replacement in Performance for
TL431 and AS431
Low Cost Solution
The SPX431L is a 3-terminal adjustable shunt voltage regulator providing a highly accurate
bandgap reference. The SPX431L acts as an open-loop error amplifier with a 2.5V temperature
compensation reference. The SPX431L's thermal stability, wide operating current (100mA) and
temperature range (0
C to 105
C) makes it suitable for a variety of applications that require a
low cost, high performance solution. SPX431L 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 manufacturer's assembly line and contribute a significant cost savings.
The output voltage may be adjusted to any value between V
REF
and 20V with two external
resistors. The SPX431L is available in TO-92, SOIC-8, SOT-89, and SOT-23-3 packages.
APPLICATIONS
Battery Operating Equipment
Adjustable Supplies
Switching Power Supplies
Error Amplifiers
Single Supply Amplifier
Monitors / VCRs / TVs
Personal Computers
BLOCK DIAGRAM
+
-
2.5V
Reference
(R)
Anode (A)
Cathode (K)
2
Rev. 8/8/02 SPX431L Precision Adjustable Shunt Regulator
Copyright 2002 Sipex Corporation
ABSOLUTE MAXIMUM RATINGS
Cathode-Anode Reverse Breakdown V
KA
....................................... 20V
Anode-Cathode Forward Current, (<10ms) I
AK
................................. 1A
Operating Cathode Current I
KA
.................................................. 100mA
Reference Input Current I
REF
........................................................ 10mA
Continuos Power Dissipation at 25
C P
D
TO-92 ..................................................................... 775mW
SOT-23 .................................................................. 200 mW
SOIC-8 .................................................................... 750mW
SOT-89 ................................................................. 1000mW
Junction Temperature T
J
........................................................... 150
C
Storage Temperature T
STG
.............................................. -65 to 150
C
Lead Temperature (Soldering 10 sec.) T
L
.................................. 300
C
NOTE: 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 condi-
tions for extended periods may affect reliability.
RECOMMENDED CONDITIONS
PARAMETER
SYMBOL
RATING
UNIT
Cathode Voltage
V
KA
V
REF
to 20
V
Cathode Current
I
K
10
mA
TYPICAL THERMAL RESISTANCES
PACKAGE
0
JA
0
JC
TYPICAL DERATING
TO-92
160
C/W 80
C/W
6.3 mW/
C
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
.
ELECTRICAL CHARACTERISTICS
Electrical characteristics at 25
C I
K
= 10mA V
K
= V
REF
, unless otherwise specified.
PARAMETER
SYMBOL
FIGURE
CONDITIONS
MIN
TYP
MAX
UNITS
SPX431LA
Reference Voltage
V
REF
2
2.490
2.503
2.515
V
V
REF
withTemp.*
TC
2
0.07
0.20
mV/
C
Ratio of Change in V
REF
V
REF
3
V
REF
to 10V
-2.7
-1.0
mV/V
to Cathode Voltage
V
K
10V to 20V
-2.0
-0.4
0.3
Reference Input Current
I
REF
3
0.7
4.0
A
I
REF
Temp Deviation
I
REF
3
T
J
= 0
C to 105
C
0.4
1.2
A
Min I
K
for Regulation
I
K(MIN)
2
0.4
1.0
mA
Off State Leakage
I
K(OFF)
4
V
REF
= 0V, V
KA
= 20V
0.04
1.0
A
Dynamic Output
Z
KA
2
z
1kHz
0.15
0.5
Impedance
I
K
= 1 to 100mA
SPX431L
Reference Voltage
V
REF
2
2.470
2.495
2.520
V
V
REF
withTemp.*
TC
2
0.07
0.20
mV/
C
Ratio of Change in V
REF
V
REF
3
V
REF
to 10V
-2.7
-1.0
mV/V
to Cathode Voltage
V
K
10V to 20V
-2.0
-0.4
0.3
Reference Input Current
I
REF
3
0.7
4.0
A
I
REF
Temp Deviation
I
REF
3
T
J
= 0
C to 105
C
0.4
1.2
A
Min I
K
for Regulation
I
K(MIN)
2
0.4
1.0
mA
Off State Leakage
I
K(OFF)
4
V
REF
= 0V, V
KA
= 20V
0.04
1.0
A
Dynamic Output
Z
KA
2
z
1kHz
0.15
0.5
Impedance
I
K
= 1 to 100mA
3
Rev. 8/8/02 SPX431L Precision Adjustable Shunt Regulator
Copyright 2002 Sipex Corporation
PARAMETER
SYMBOL
FIGURE
CONDITIONS
MIN
TYP
MAX
UNITS
SPX431LC
Reference Voltage
V
REF
2
2.445
2.495
2.545
V
V
REF
withTemp.*
TC
2
0.07
0.20
mV/
C
Ratio of Change in V
REF
V
REF
3
V
REF
to 10V
-2.7
-1.0
mV/V
to Cathode Voltage
V
K
10V to 20V
-2.0
-0.4
0.3
Reference Input Current
I
REF
3
0.7
4.0
A
I
REF
Temp Deviation
I
REF
3
T
J
= 0
C to 105
C
0.4
1.2
A
Min I
K
for Regulation
I
K(MIN)
2
0.4
1.0
mA
Off State Leakage
I
K(OFF)
4
V
REF
= 0V, V
KA
= 16V
0.04
1.0
A
Dynamic Output
Z
KA
2
z
1kHz
0.15
0.5
Impedance
I
K
= 1 to 100mA
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
ppm
%
mV
Junction Temperature (
C)
TC in ppm/
C =
TC in %/
C =
TC in mV/
C =
V
REF
(mV)
T
A
(
V
REF
at 25
C
)
T
A
V
REF
x 100
(
V
REF
at 25
C
)
T
A
V
REF
x 10
6
CALCULATING AVERAGE TEMPERATURE COEFFICIENT (TC)
Figure 1. V
REF
VS Temperature.
Operating Range (T
J
) = 0
C to 105
C.
* See appropiate test circuit (Figure 2)
4
Rev. 8/8/02 SPX431L Precision Adjustable Shunt Regulator
Copyright 2002 Sipex Corporation
-2
-1
0
1
2
3
150
125
100
75
50
25
0
-25
-50
-75
-100
V
KA
Cathode Voltage (V)
I
K
Cathode Current (mA)
V
KA
= V
REF
0
C to 105
C
-60
-30
0
30
60
90
120
2.53
2.52
2.51
2.50
2.49
2.48
2.47
2.46
2.45
T
A
Ambient Temperature (
C)
V
REF
Reference V
o
ltage (V)
V
KA
= V
REF
I
K
= 10mA
TYPICAL PERFORMANCE CHARACTERISTICS
Figure 5. High Current Operating Characteristics
Figure 6. Reference Voltage VS Ambient Tempetature
TEST CIRCUITS
I
REF
V
KA =
V
REF
V
IN
I
K
I
REF
V
KA
V
IN
I
K
(V
REF
)
R1
R2
V
KA
V
IN
I
K (OFF)
Figure 2. Test Circuit for V
KA
= V
REF
Figure 3. Test Circuit for V
KA
> V
REF
Figure 4. Test Circuit for I
KOFF
-1.0
0
1.0
2.0
3.0
900
800
700
600
500
400
300
200
100
0
-100
-200
V
KA
Cathode Voltage (V)
I
K
Cathode Current (
A)
V
KA
= V
REF
0
to 105
C
105
C
25
C
-0
C
-60
-30
0
30
60
90
120
3.0
2.5
2.0
1.5
1.0
0.5
0
T
A
Ambient Temperature (
C)
I
REF
Reference Input Current (
A)
R1 = 10k
R2 =
I
K
= 10mA
Figure 7. Low Current Operating Characteristics.
Figure 8. Reference Input Current VS Ambient
Temperature.
5
Rev. 8/8/02 SPX431L Precision Adjustable Shunt Regulator
Copyright 2002 Sipex Corporation
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
0
3
6
9
12 15
18
21
24
27 30
0
-10
-20
-30
-40
-50
V
KA
Cathode Voltage (V)
V
REF
(mV)
0
C
25
C
75
C
125
C
I
KA
= 10mA
Figure 9. Reference Voltage Line Regulation VS
Cathode Voltage and T
AMBIENT
10
100
1K
10K
100K
70
60
50
40
30
20
10
0
f Frecuency
(Hz)
Noise V
o
ltage nV/Hz
V
KA
= V
REF
I
K
= 10mA
T
A
= 25
C
Figure 10. Noise Voltage VS Frequency
-60
-30
0
30
60
90
120
0.150
0.125
0.100
0.075
0.050
0.025
0.0
T
A
Free Air Temperature
Z
KA
Dynamic Impedance (
)
V
KA
= V
REF
I
K
= 1 to 100mA
f
1kHz
Figure 11. Low Frequency Dynamic Output Impedance
VS T
AMBIENT
10
100
1K
10K
100K
1M
10M
START 10.000Hz
STOP 50 000 000.000Hz
REF LEVEL
60.000dB
0.0deg
/DIV
10.000dB
45.000deg
MARKER 25 297
MAG (A/R)
MARKER 25 297
PHASE (A/R)
698.000 Hz
-0.025 dB
698.000 Hz
93.320 deg
GAIN
PHASE
60dB
50dB
40dB
30dB
20dB
10dB
0dB
-10dB
-20dB
-30dB
-40dB
215
180
135
90
45
0
-45
-90
-135
-180
-215
Figure 12. Small Signal Gain and Phase VS Frequency;
I
K
= 10mA, T
A
= 25
C
I
K
V
IN
9
F
15k
8.25k
V
OUT
GND
230
Figure 13. Test Circuit for Gain and Phase Frequency
Response
V
IN
V
OUT
V
IN
V
OUT
Figure 14. F
Z
= 100kHz, I
K
= 10mA, T
A
= 25
C
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