Low Voltage Adjustable
Shunt Regulator
POWER MANAGEMENT
Description
The SC431L is a three terminal adjustable shunt
regulator with thermal stability guaranteed over
temperature. The output voltage can be adjusted to any
value from 1.24V (V
REF
) to 20V with two external
resistors. The SC431L has a typical dynamic output
impedance of 0.05Ω. Active output circuitry provides a
very sharp turn on characteristic, making the SC431L an
excellent replacement for zener diodes.
The SC431L shunt regulator is available with four volt-
age tolerances (0.25%, 0.5%, 1.0% and 2.0%), two
operating temperature ranges (commercial and indus-
trial) and two package options (SOT-23-3 and SOT-23-
5). This allows the designer the opportunity to select the
optimum combination of cost and performance for their
application.
SC431L
Features
Low voltage operation (down to 1.24V)
Wide operating current range 100µA to 100mA
Low dynamic output impedance 0.05
Ω
typ.
Trimmed bandgap design ± 0.25%
Upgrade for TLV431A
Available in SOT-23-3 and SOT-23-5 packages
Applications
Linear Regulators
Adjustable Supplies
Switching Power Supplies
Battery Operated Computers
Instrumentation
Computer Disk Drives
Typical Application Circuit
(1)(2)
Notes:
1) Set V
OUT
according to the following equation:
R1
V
OUT
=
V
REF
1
+
+
I
REF
R1
R2
2) Choose the value for R as follows:
•
The maximum limit for R should be such that the
cathode current, I
Z
, is greater than the minimum
operating current (100µA) at V
IN(MIN)
.
•
The minimum limit for R should be such that I
Z
does
not exceed 100mA under all load conditions, and the
instantaneous turn-on value for I
Z
does not exceed
150mA. Both of the following conditions must be met:
R
min
≥
V
IN (max)
150 mA
(to limit instantaneous turn-on I
Z
)
R
min
≥
V
IN (max)
−
V
OUT
I
OUT (min)
+
100 mA
(to limit I
Z
under normal
operating conditions)
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SC431L
POWER MANAGEMENT
Absolute Maximum Ratings
Parameter
Cathode Voltage
Continous Cathode Current
Reference Input Current
Power Dissipation at T
A
= 25°C
SOT-23-3
SO-8
Thermal Resistance
SOT-23-3
SOT-23-5
Operating Ambient Temperature Range
S C 431LC
S C 431LI
Operating Junction Temperature Range
S C 431LC
S C 431LI
Storage Temperature Range
Lead Temperature (Soldering) 10 seconds
ESD Rating (Human Body Model)
Symbol
V
Z
I
Z
I
REF
P
D
Maximum
20
100
3
0.37
0.49
336
256
0 to +70
-40 to +85
0 to +150
-40 to +150
-65 to +150
300
2
Units
V
mA
mA
W
θ
J A
°C/W
T
A
°C
T
J
T
STG
T
LEAD
V
ESD
°C
°C
°C
kV
Electrical Characteristics
Unless specified:T
A
= 25°C. Values in
bold
apply over full operating ambient temperature range.
SC431L 0.25%
Parameter
Reference Voltage
Symbol
V
REF
Condition
V
Z
= V
REF
, I
Z
= 10mA
(1)
Min
1.237
1.224
V
REF
Temp Deviation
Ratio of Change in
V
REF
to Change in V
Z
Reference Input
Current
I
REF
Temperature
Deviation
Off-State Cathode
Current
V
D EV
V
Z
= V
REF
, I
Z
= 10mA
(1)
I
Z
= 10mA,
∆V
Z
= 16V to V
REF
10
-1.0
Typ
1.240
Max
1.243
1.256
25
-2.7
SC431L 0.5%
Min
1.234
1.222
10
-1.0
Typ
1.240
Max
1.246
1.258
25
-2.7
mV
mV/V
Units
V
∆
V
REF
∆
V
Z
I
REF
I
REF(DEV)
I
Z (OFF)
R1 = 10k
Ω
, R2 =
∞,
I
Z
= 10mA
(2)
R1 = 10k
Ω
, R2 =
∞,
I
Z
= 10mA
(2)
V
REF
= 0V, V
Z
= 6V
(3)
V
REF
= 0V, V
Z
= 16V
(3)
0.15
0.1
0.125
0.135
0.5
0.4
0.150
0.150
0.15
0.1
0.125
0.135
0.5
0.4
0.150
0.150
µA
µA
µA
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SC431L
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Unless specified:T
A
= 25°C. Values in
bold
apply over full operating ambient temperature range.
(Continued from page 2)
Parameter
Dynamic Output
Impedance
Minimum Operating
Current
Symbol
r
Z
I
Z (MIN)
Condition
f < 1kHz, V
Z
= V
REF
I
Z
= 100µA to 100mA
(1)
V
Z
= V
REF(1)
SC431L 0.25%
Min
Typ
0.05
20
Max
0.15
100
SC431L 0.5%
Min
Typ
0.05
20
Max
0.15
100
Units
Ω
µA
S C 431L 1%
Parameter
Reference Voltage
Symbol
V
REF
Condition
V
Z
= V
REF
, I
Z
= 10mA
(1)
Min
1.228
1.215
V
REF
Temp Deviation
Ratio of Change in
V
REF
to Change in V
Z
Reference Input
Current
I
REF
Temperature
Deviation
Off-State Cathode
Current
Dynamic Output
Impedance
Minimum Operating
Current
r
Z
I
Z (MIN)
V
D EV
V
Z
= V
REF
, I
Z
= 10mA
(1)
I
Z
= 10mA,
∆V
Z
= 16V to V
REF
10
-1.0
Typ
1.240
Max
1.252
1.265
25
-2.7
S C 431L 2%
Min
1.215
1.200
10
-1.0
Typ
1.240
Max
1.265
1.280
35
-2.7
mV
mV/V
Units
V
∆
V
REF
∆
V
Z
I
REF
I
REF(DEV)
I
Z (OFF)
R1 = 10k
Ω
, R2 =
∞,
I
Z
= 10mA
(2)
R1 = 10k
Ω
, R2 =
∞,
I
Z
= 10mA
(2)
V
REF
= 0V, V
Z
= 6V
(3)
V
REF
= 0V, V
Z
= 16V
(3)
f < 1kHz, V
Z
= V
REF
I
Z
= 100µA to 100mA
(1)
V
Z
= V
REF(1)
0.15
0.1
0.125
0.135
0.05
20
0.5
0.4
0.150
0.150
0.15
100
0.15
0.1
0.125
0.135
0.05
20
0.5
0.4
0.150
0.150
0.15
100
µA
µA
µA
Ω
µA
Notes:
(1) See Test Circuit 1 on page 4.
(2) See Test Circuit 2 on page 4.
(3) See Test Circuit 3 on page 4.
Recommended Operating Conditions
Min
Cathode Voltage, V
Z
Cathode Current, I
Z
V
REF
100µA
Max
16
100
Symbol
V
mA
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SC431L
POWER MANAGEMENT
Test Circuits
Test Circuit 1
V
Z
= V
REF
Test Circuit 2
V
Z
> V
REF
Test Circuit 3
Off-State
Pin Configurations
SOT-23-3 (Top View)
SOT-23-5 (Top View)
Block Diagram
Symbol
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SC431L
POWER MANAGEMENT
Ordering Information
P ackag e
T
J
(°C)
0.25%
SOT-23-3
(1)(2)
0 to +150
SC431LCSK-.25TR
SC431LCSK-.25TRT
-40 to +150
SC431LISK-.25TR
SC431LISK-.25TRT
SOT-23-5
(1)(2)
0 to +150
SC431LC5SK.25TR
0.5%
SC431LCSK-.5TR
SC431LCSK-.5TRT
SC431LISK-.5TR
SC431LISK-.5TRT
SC431LC5SK-.5TR
Tolerance
1.0%
SC431LCSK-1TR
SC431LCSK-1TRT
SC431LISK-1TR
SC431LISK-1TRT
SC431LC5SK-1TR
2.0%
SC431LCSK-2TR
SC431LCSK-2TRT
SC431LISK-2TR
SC431LISK-2TRT
SC431LC5SK-2TR
SC431LC5SK-2TRT
SC431LI5SK-2TR
SC431LI5SK-2TRT
SC431LC5SK.25TRT SC431LC5SK-.5TRT SC431LC5SK-1TRT
-40 to +150
SC431LI5SK.25TR
SC431LI5SK.25TRT
SC431LI5SK-.5TR
SC431LI5SK-.5TRT
SC431LI5SK-1TR
SC431LI5SK-1TRT
Notes:
(1) Only available in tape and reel packaging. A reel contains 3000 devices.
(2)
“T” at end of part number indicates “lead free”.
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