©2011 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev. 1.0.7
Features
• Programmable Output Voltage to 36 Volts
• Low Dynamic Output Impedance 0.2Ω Typical
• Sink Current Capability of 1.0 to 100mA
• Equivalent Full-Range Temperature Coefficient of
50ppm/°C Typical
• Temperature Compensated for Operation Over Full Rated
Operating Temperature Range
• Low Output Noise Voltage
• Fast T urn-on Response
Description
The KA431S/KA431SA/KA431SL are three-terminal
adjustable regulator series with a guaranteed thermal
stability over applicable temperature ranges. The output
voltage may be set to any value between VREF
(approximately 2.5 volts) and 36 volts with two external
resistors These devices have a typical dynamic outpu t
impedance of 0.2Ω. Active output circuitry provides a very
sharp turn on characteristic, making these devices excellent
replacement for zener diodes in many applications.
SOT-23F
12
3
MF- 1.Cathode 2. Ref 3. Anode
MF2- 1. Ref 2. Cathode 3. Anode
Internal Block Diagram
2.5 Vref
CATHODE
ANODE
REFERENCE
ANODE(A)
REFERENCE (R)
CATHODE (K)
+
-
KA431S/KA431SA/KA431SL
Programmable Shunt Regulator
KA431S/KA431SA/KA431SL
2
Absolute Maximum Ratings
(Operating temperature range applies unless otherwise specified.)
Note :
1. Thermal resistance test board
Size: 76.2mm * 114.3mm * 1.6mm (1S0P)
JEDEC Standard: JESD51-3, JESD51-7
2. Assume no ambient airflow.
3. TJMAX = 150°C, Ratings apply to ambient temperature at 25°C
4. Power dissipation calculation: PD = (TJ - TA)/RθJA
Recommended Operating Conditions
Parameter Symbol Value Unit
Cathode Voltage VKA 37 V
Cathode Current Range (Continuous) IKA -100 ~ +150 mA
Reference Input Current Range IREF -0.05 ~ +10 mA
Thermal Resistance Junction-Air (Note1,2)
MF Suffix Package RθJA 350 °C/W
Power Dissipation (Note3,4)
MF Suffix Package PD350 mW
Junction Temperature TJ150 °C
Operating Temperature Range TOPR -25 ~ +85 °C
Storage Temperature Range TSTG -65 ~ +150 °C
Parameter Symbol Min. Typ. Max. Unit
Cathode Voltage VKA VREF -36V
Cathode Current IKA 1.0 - 100 mA
KA431S/KA431SA/KA431SL
3
Electrical Characteristics
(TA = +25°C, unless otherwise specified)
•T
MIN = -25°C, TMAX = +85°C
Parameter Symbol Conditions KA431S KA431SA KA431SL Unit
Min. Typ. Max. Min. Typ. Max. Min. Typ. Max.
Reference Input
Voltage VREF VKA=VREF,
IKA=10mA 2.450 2.500 2.550 2.470 2.495 2.520 2.482 2.495 2.508 V
Deviation of
Reference
Input Voltage
Over-
Temperature
ΔVREF/
ΔTVKA=VREF,
IKA=10mA
TMIN≤TA≤TMAX - 4.5 17 - 4.5 17 - 4.5 17 mV
Ratio of Change
in Reference
Input Voltage
to the Change in
Cathode
Voltage
ΔVREF/
ΔVKA IKA
=10mA
ΔVKA=10
V-VREF - -1.0 -2.7 - -1.0 -2.7 - -1.0 -2.7
mV/V
ΔVKA=36
V-10V - -0.5 -2.0 - -0.5 -2.0 - -0.5 -2.0
Reference Input
Current IREF IKA=10mA,
R1=10kΩ,R2=∞-1.54 -1.54 -1.54
μ
A
Deviation of
Reference
Input Current
Over Full
Temperature
Range
ΔIREF/ΔT
IKA=10mA,
R1=10kΩ,R2=∞
TA =Full Range - 0.4 1.2 - 0.4 1.2 - 0.4 1.2
μ
A
Minimum
Cathode Cur-
rent for
Regulation
IKA(MIN) VKA=VREF - 0.45 1.0 - 0.45 1.0 - 0.45 1.0 mA
Off - Stage
Cathode
Current IKA(OFF) VKA=36V,
VREF=0 - 0.05 1.0 - 0.05 1.0 - 0.05 1.0
μ
A
Dynamic
Impedance ZKA VKA=VREF,
IKA=1 to 100mA
f ≥1.0kHz - 0.15 0.5 - 0.15 0.5 - 0.15 0.5 Ω
KA431S/KA431SA/KA431SL
4
Test Circuits
Figure 1. Test Circuit for VKA=VREF Figure 2. Test Circuit for VKA≥VREF
KA431S KA431S
KA431S
Figure 3. Test Circuit for lKA(OFF)
KA431S/KA431SA/KA431SL
5
Typical Performance Characteristics
-2 -1 0 1 2 3
-100
-50
0
50
100
150
VKA = VREF
TA = 25oC
IK, Cathode Current (mA)
VKA, Cathode Voltage (V)
-50 -25 0 25 50 75 100 125
0.000
0.025
0.050
0.075
0.100
Ioff, Off-State Cathode Current (uA)
TA, Ambient Temperature (oC)
1k 10k 100k 1M 10M
-10
0
10
20
30
40
50
60
TA = 25oC
IKA = 10mA
Open Loop Voltage Gain (dB)
Frequency (Hz)
-10123
-200
0
200
400
600
800
IKA(MIN)
VKA = VREF
TA = 25oC
IKA, CATHODE CURRENT (uA)
VKA, CATHODE VOLTAGE (V)
-50 -25 0 25 50 75 100 125
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Iref, Reference Input Current (uA)
TA, Ambient Temperature (oC)
0 4 8 12 16 20
0
1
2
3
4
5
6
TA=25oC
OUTPUT
INPUT
Voltage Swing (V)
Time (us)
Figure 4. Cathode Current vs. Cathode Voltage Figure 5. Cathode Current vs. Cathode Voltage
Figure 6. OFF-State Cathode Current vs.
Ambient Temperature Figure7. Reference Input Current vs.
Figure 8. Small Signal Voltage Amplification vs. Frequency Figure 9. Pulse Response
Ambient Temperature
KA431S/KA431SA/KA431SL
6
Typical Performance Characteristics (Contin ued)
100p 1n 10n 100n 1ٛ10ٛ
0
20
40
60
80
100
120
140
B
A
A VKA = Vref
B VKA = 5.0 V @ IK = 10mA
TA = 25oC
IK, CATHODE CURRENT(mA)
CL, LOAD CAPACITANCE
Figure 10. Stability Boundary Conditions Figure 11. Anode-Reference Diode Curve
Figure 12. Reference-Cathode Diode Curve
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
0
1
2
3
4
5
Current(mA)
Anode- Ref. Voltage(V)
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
0
1
2
3
4
5
Current(mA)
Ref.-Cathode Voltage(V)
stable stable
KA431S/KA431SA/KA431SL
7
Typical Application
VO1R1
R2
-------
+
⎝⎠
⎛⎞
Vref
=
KA431S
VOVref 1R1
R2
-------
+
⎝⎠
⎛⎞
=
KA431S
VO1R1
R2
-------
+
⎝⎠
⎛⎞
Vref
=
KA431S
KA431S KA431S
Figure 13. Shunt Regulator Figure 14. Output Control for
-Three-Termianl Fixed Regulator Figure 15. High Current Shunt Regulator
Figure 16. Current Limit or Current Source Figure 17. Constant-Current Sink
KA431S/KA431SA/KA431SL
8
Mechanical Dimensions
Package Dimensions in millimeters
Marking
SOT-23F
43A 43B 43C
2% tolerance 1% tolerance 0.5% tolerance
43A 43B 43C
2% tolerance 1% tolerance 0.5% tolerance
43D 43E 43F
MF-
MF2-
KA431S/KA431SA/KA431SL
9
Ordering Information
Product Number Output Voltage Tolerance Package Operating Temperature
KA431SLMF 0.5% SOT-23F
-25 ~ +85°C
KA431SAMF 1% SOT-23F
KA431SMF 2% SOT-23F
KA431SLMF2 0.5% SOT-23F
KA431SAMF2 1% SOT-23F
KA431SMF2 2% SOT-23F
KA431S/KA431SA/KA431SL
2/22/11 0.0m 001
Stock#DS400506
© 2011 Fairchild Semiconductor Corporation
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