©2005 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev. 1.0.6
Features
• Programmable Output Voltage to 36 Volts
• Low Dynamic Output Impedance 0.20 Typical
• Sink Current Capability of 1.0 to 100mA
• Equivalent Full-Range Tempe ratu re Coefficient of
50ppm/°C Typical
• Temperature Compensated for Operation Over Full Rated
Operating Temperatur e Ra ng e
• Low Output Noise Voltage
• Fast Turn-on Respons e
Description
The KA431S/KA431SA/KA431SL are three-term inal
adjustable regulator series with a guaranteed thermal
stability over applicable temperature ranges. The output
voltage may be set to any value between V
REF
(approximately 2.5 volts) and 36 volts with two external
resistor s These devi ces have a typical dynamic ou tput
impedance of 0.2W Active output circuitry provides a very
sharp turn on characteristic, makin g these dev ices excellent
replacement for zener diodes in many applications.
SOT-23F
12
3
MF- 1.Cathod e 2. Ref 3. A node
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 Regulat or
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. T
JMAX
= 150
°C
, Ratings apply to ambient temperatu re at 2 5
°C
4. Power dissipation calculation: P
D
= (T
J
- T
A
)/
R
θJA
Recommended Operating Conditions
Parameter Symbol Value Unit
Cathode Voltage V
KA
37 V
Cathode Current Range (Continuous) I
KA
-100 ~ +150 mA
Reference Input Current Range I
REF
-0.05 ~ +10 mA
Thermal Resistance Junction-Air (Note1,2)
MF Suffix Package R
θJA
350 °C/W
Power Dissipation (Note3,4)
MF Suffix Package P
D
350 mW
Junction Temperature T
J
150 °C
Operating Temperature Range T
OPR
-25 ~ +85 °C
Storage Temperature Range T
STG
-65 ~ +150 °C
Parameter Symbol Min. Typ. Max. Unit
Cathode Voltage V
KA
V
REF
-36V
Cathode Current I
KA
1.0 - 100 mA
KA431S/KA431SA/KA431SL
3
Electrical Characteristics
(T
A
= +25°C, unless otherwise specified)
•T
MIN
= -25°C, T
MAX
= +85°C
Parameter Symbol Conditions KA431S KA431SA KA431SL Unit
Min. Typ. Max. Min. Typ. Max. Min. Typ. Max.
Refere nce Input
Voltage V
REF
V
KA
=V
REF
,
I
KA
=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
∆VREF/
∆TVKA=VREF,
IKA=10mA
TMIN≤TA≤TMAX -4.5 17 -4.5 17 -4.5 17 mV
Ratio of Change
in Referenc e
Input Voltage
∆VREF/
∆VKA IKA
=10mA
∆VKA=10
V-VREF - -1.0 -2.7 - -1.0 -2.7 - -1.0 -2.7
mV/V
to t he C ha nge in
Cathode
Voltage
∆VKA=36
V-10V - -0.5 -2.0 - -0.5 -2.0 - -0.5 -2.0
Refere nce Input
Current IREF IKA=10mA,
R1=10kΩ,R2=∞-1.54 -1.54 -1.54
µ
A
Deviation of
Reference
Input Current
Over Fu ll
Temperature
Range
∆IREF/∆T
IKA=10mA,
R1=10kΩ,R2=∞
TA =Full Rang e -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 Circ uit for V
KA
=V
REF
Figure 2. Test Circuit for V
KA
≥V
REF
KA431S KA431S
KA431S
Figure 3. Test Circuit for l
KA(OFF)
KA431S/KA431SA/KA431SL
5
Typical Performance Characteristics
-2-10123
-100
-50
0
50
100
150
V
KA
= V
REF
T
A
= 25
o
C
I
K
, Cathode Cur rent (m A)
V
KA
, Cathode Voltag e (V)
-50-250 255075100125
0.000
0.025
0.050
0.075
0.100
I
off
, Off-State Cathode Current (uA)
T
A
, Ambient Temperature (
o
C)
1k 10k 100k 1M 10M
-10
0
10
20
30
40
50
60
T
A
= 25
o
C
I
KA
= 10mA
Open Loop Voltage Gai n (dB)
Frequency (Hz)
-10123
-200
0
200
400
600
800
I
KA(MIN)
V
KA
= V
REF
T
A
= 25
o
C
I
KA
, CATHODE CURRENT (uA)
V
KA
, 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
I
ref
, Reference Input Current (uA)
T
A
, Ambient Temperature (
o
C)
048121620
0
1
2
3
4
5
6
T
A
=25
o
C
OUTPUT
INPUT
Voltage Swing (V)
Time (us)
Figure 4. Cathode Current vs. Cathode Voltage Figur e 5. Cathode Current vs. Cathode Voltage
Figure 6. OFF-State Cathode Current vs.
Ambient Te mperature Figure7. R efere nce Input Curre nt vs.
Figure 8. Small Signal Voltage Amplification vs. Frequency Figure 9. Pulse Response
Ambient Temperature
KA431S/KA431SA/KA431SL
6
Typical Performance Characteristics
(Continu ed)
100p 1n 10n 100n 1
!
10
!
0
20
40
60
80
100
120
140
B
A
A V
KA
= Vref
B V
KA
= 5.0 V @ I
K
= 10
mA
T
A
= 25
o
C
I
K
, CATHODE CURRENT(mA)
C
L
, LOAD CAPACITANCE
Figure 10. Stability Boundary Conditions Figur e 11. Anode-Reference Di ode 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
V
O
1R
1
R
2
-------
+


V
ref
=
KA431S
V
O
V
ref
1R
1
R
2
-------
+


=
KA431S
V
O
1R
1
R
2
-------
+


V
ref
=
KA431S
KA431S KA431S
Figure 13
.
Shun t Regulator Figure 14
.
Output Control for
-Three-Termianl Fixed Regulator Figure 15. High Current Shunt Regulator
Figure 16. Current Lim it or Current Source Figu re 17. Cons tant-Current Sink
KA431S/KA431SA/KA431SL
8
Mechanic al Dime nsions
Package Dimensions in millimeters
SOT-23F
KA431S/KA431SA/KA431SL
9
Marking
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
6/8/05 0. 0m 001
Stock#DSxxxxxxxx
2005 Fairchild Semiconductor Corpor ation
LIFE SU PP ORT POL I CY
FAIRCHILD’ S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL CO MPONENTS IN LIF E SUPPORT DEVICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
CORPORA TION. As used he rein :
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and (c) whose failure to
perform when properly used in accordance with
instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of the
user.
2. A critical component in any component of a life support
dev ice or syst em who se failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effec tiveness .
www.fairchildsemi.com
DISCLAIMER
FAIRC HILD SEMICONDU CTOR RESERVES THE RIGHT TO MAKE CHANGES WI THOUT FURTHE R NOTICE TO ANY
PRO DUCTS HEREIN TO IMPROVE RELIABILITY , FUNCTION OR DESIGN. FAIRCH IL D DOES NOT ASSUME ANY
LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER
DOES IT CONVE Y ANY LI CENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS O F OTHERS.
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