Rev. 10/25/00
Precision Adjustable
Shunt Regulator
FEATURES
APPLICATIONS
• Voltage Tolerance ................................................ 0.4%
• Battery Operating Equipment
• Wide Operating Current .....................1mA to 150mA
• Adjustable Supplies
• Extended Temperature Range ........... -55°°°°C to 125°°°°C
• Switching Power Supplies
• Low Temperature Coefficient ........................30 ppm/°C
• Error Amplifiers
• Improved Replacement in Performance for LT1431
• Single Supply Amplifiers
• Offered In Small Low Power SOT-89 Package
• Monitors / VCR / TV
• Low Output Noise
• Personal Computers
PRODUCT DESCRIPTION
The SPX1431 is a 3-terminal Adjustable Shunt Voltage Regulator providing a highly accurate 0.4% bandgap reference. SPX1431 acts
as an open-loop error amplifier with a 2.5V temperature compensation reference. The SPX1431 thermal stability, wide operating
current (150mA) and temperature range (125
°C) makes it suitable for all varieties of applications that are looking for a low cost
solution with high performance. SPX1431 tolerance of 0.4% 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.
In the standard shunt configuration, the combination of low temperature coefficient (T.C.), sharp turn-on characteristics, low output
impedance and programmable output voltage that makes this precision reference an excellent error amplifier.
The SPX1431 is a direct improved replacement for the SPX431 and TL431 in low voltage, low current applications.
PIN CONFIGURATIONS
SPX1431
SOT-89 (M1)
Front View
1
REF
2
ANODE
3
CATHODE
1
3
2
TO-92 (N)
Bottom View
REF
ANODE
CATHODE
Standard Pinout
Top View
2
1
3
4
8
7
6
5
SPX1431
ANODE
N/C
REF
ANODE
N/C
ANODE
ANODE
CATHODE
8-Pin Surface Mount (S)
SOT-23-5 (M5)
3
2
1
Top View
SPX1431
5
4
REF
ANODE
N/C
N/C
CATHODE
SPX1431
Rev. 10/25/00
SPX1431
ABSOLUTE MAXIMUM RATINGS
Parameter Symbol
Rating
Units
Cathode-Anode Reverse Breakdown
V
KA
37 V
Anode-Cathode Forward Current
I
AK
1 A
Operating Cathode Current
I
KA
250 mA
Reference Input Current
I
REF
10 mA
Continuous Power Dissipation at 25
°C
TO-92
SOT-23
8L SOIC
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
175
° C/W 45° C/W
5.7 mW/
°C
SOT-89
110
° C/W
8
° C/W
9.1 mW/
°C
2.5V
+
-
REFERENCE
(R)
CATHODE (K)
ANODE (A)
Rev. 10/25/00
I
K
I
REF
V
IN
V
KA
= V
REF
V
IN
V
KA
I
K
R
1
R
2
(V
REF
)
Figure 1b. Test Circuit 2
Figure 1a. Test Circuit 1
V
IN
V
KA
I
K (OFF)
Figure 1c. Test Circuit 3
I
REF
SPX1431
ELECTRICAL CHARACTERISTICS
are guaranteed over full junction temperature range (-55
°C to 125°C). Ambient
temperature must be derated based on power dissipation and package thermal characteristics. The conditions are: V
KA
= V
REF
and
I
K
= 10mA, unless otherwise specified.
Parameter
Symbol
Test Conditions
Test Circuit
Min
Typ
Max
Units
Reference Voltage
V
REF
T
A
= 25
°C
1 2.490
2.500
2.510
V
Over
Temp.
1
2.465
2.535
V
V
REF
with Temp*
TC
1
0.06
0.16
mV/
°
C
Ratio of Change in V
REF
to Cathode Voltage
V
REF
V
K
= 3V to 36V
2
-2
-1.1
mV/V
Reference Input Current
I
REF
R
I
= 10 k; R
2
=
2
0.7
1.9
µA
I
REF
Temp Deviation
I
REF
Over
Temp. 2
0.4
1.2
µA
Min I
K
for Regulation
I
K (min)
1
0.4
1
mA
Off State Leakage
I
K (off)
V
REF
= 0V, V
KA
=
36V
3
0.04
250
nA
Dynamic Output
Impedance
Z
KA
f
< 1 kHz I
K
1 to
100mA
1
0.15
0.2
Ω
Calculating Average Temperature Coefficient (TC)
TEST CIRCUITS
ppm
mV
TC in mV/°C =
∆V
REF
(mV)
∆T
A
TC in %/°C =
V
REF
at 25°C
∆T
A
∆V
REF
)
)
x 100
TC in ppm/°C =
V
REF
at 25°C
∆T
A
∆V
REF
)
)
x 10
6
∆Τ
-55
0.06 mV/°C
∆V
REF
0
0
0
%
-20
-10
0.5
5000
Temperature (°C)
0.002 %/°C
24 ppm/°C
-25
0
25
50
75 100 125
Rev. 10/25/00
SPX1431
TYPICAL PERFORMANCE CURVES
High Current Operating Characteristics
V
KA
- Cathode Voltage (V)
-2
-1
0
1
2
3
-100
-75
-50
-25
0
25
50
75
100
125
150
Figure 3
I
K
- Cathode Current (mA)
V
KA
= V
REF
Temperature Range: - 55 to 125 °C
Off State Leakage
-60
-30
0
30
60
90
120
0.01
0.1
1
10
100
Figure 4
T
A
- Ambient Temperature ( °C)
I
Z
off - Off State Cathode Current (nA)
V
KA
= 18V
V
REF
= 0V
T
A
- Ambient Temperature ( °C)
Figure 5
Reference Voltage vs. Ambient Temperature
V
R
EF
- Reference Voltage (V)
-60
-30
0
30
60
90
120
2.45
2.46
2.47
2.48
2.49
2.50
2.51
2.52
2.53
V
KA
= V
REF
I
K
= 10
mA
V
REF
= 2.500 V at 25 °C
Low Current Operating Characteristics
900
800
700
600
500
400
300
200
100
0
-100
-200
1.0
-1.0
2.0
0
3.0
V
KA
- Cathode Voltage (V)
I
K
- Cathode Current (
µµµµ
A)
V
KA
= V
REF
Temperature Range: - 55 to 125 °C
125 °C
25 °C
-55 °C
Figure 2
Rev. 10/25/00
SPX1431
TYPICAL PERFORMANCE CURVES
30
Noise Voltage nV/vHz
T
A
- Ambient Temperature ( °C)
Figure 6
Reference Input Current
I
R
EF
- Reference Input Current (
µµµµ
A)
-60
-30
0
30
60
90
120
0
R1 = 10 k
Ω
R2 =
∞
I
K
= 10 mA
0.5
1.0
1.5
2.0
2.5
3.0
Figure 7
Reference Voltage Line Regulation
V
KA
- Cathode Voltage (V)
V
REF
- Change in Reference Voltage (mV)
0
-10
-20
-30
-40
-50
0
3
6
9
12
15
18
21
24
27
125 °C
75 °C
25 °C
0 °C
-55 °C
100 k
Noise Voltage
Figure 8
f - Frequency (Hz)
70
20
30
40
10
50
60
10
100
1 k
10 k
0
V
KA
= V
REF
I
K
= 10 mA
T
A
= 25 C
T
A
- Free Air Temperature
Figure 9
Low Frequency Dynamic Output Impedance
Z
K
A
- Dynamic Impedance (
ΩΩΩΩ
)
-60
-30
0
30
60
90
120
0.0
V
KA
= V
REF
I
KA
= 1 to 100 mA
f < 1 kHz
0.025
0.050
0.075
0.100
0.125
0.150
Rev. 10/25/00
SPX1431
TYPICAL PERFORMANCE CURVES
Figure 11
GND
OUT
Figure 10
Dynamic Output Impedance
f - Frequency (Hz)
Z
KA
- Dynamic Impedance (
ΩΩΩΩ
)
100
0.1
1.0
10
1 k
10 k
100 k
1 M
10 M
0.01
T
A
= 25 °C
I
K
= 1 to 100 mA
f - Frequency (Hz)
1 k
10 k
100 k
1 M
10 M
Small Signal Voltage Gain vs. Frequency
A
V
- Small Signal Voltage Gain (dB)
70
20
30
40
10
50
60
0
Temperature Range: -55 to 125 °C
I
K
= 10 mA
9
µF
15 k
8.25 k
230
Ω
I
K
Rev. 10/25/00
SPX1431
TYPICAL PERFORMANCE CURVES
Figure 12
Figure 13
Pulse Response
t - Time (
µ
µµ
µs)
Input and Output Voltages (V)
12
-1
0
1
2
3
4
5
6
11
10
9
8
7
6
5
4
3
2
1
0
OUTPUT
INPUT
OUT
GND
220
Ω
f
P
= 100 kHz
INPUT
MONITOR
50
Ω
Stability Boundary Conditions
C
L
- Load Capacitance (pF)
I
K
- Cathode Current (mA)
10
7
10
6
10
5
10
4
10
3
10
2
10
1
10
0
0
10
20
30
40
50
60
70
80
90
100
STABILITY
REGION
T
A
= 25 °C
A: V
KA
= V
REF
B: V
KA
= 5V at I
K
= 10 mA
C: V
KA
= 10V at I
K
= 10 mA
D: V
KA
= 15V at I
K
= 10 mA
D
C
A
B
150
Ω
10 k
I
K
C
L
Rev. 10/25/00
SPX1431
ORDERING INFORMATION
Ordering No. Precision
Output Voltage
Packages
SPX1431M5
0.4%
2.5V
5 Lead SOT-23
SPX1431M1
0.4%
2.5V
3 Lead SOT-89
SPX1431S
0.4%
2.5V
8 Lead SOIC
SPX1431N
0.4%
2.5V
3 Lead TO-92
SIGNAL PROCESSING EXCELLENCE
Sipex Corporation
Headquarters and Main Offices:
22 Linnell Circle
Billerica, MA 01821
TEL: (978) 667-8700
FAX: (978) 670-9001
e-mail: sales@sipex.com
233 South Hillview Drive
Milpitas, CA 95035
TEL: (408) 935-7600
FAX: (408) 934-7500
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described
hereing; neither does it convey any license under its patent rights nor the rights of others.
Corporation