Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
1.24V Adjustable Shunt Regulator
B431L
Pin Connection
Ordering Information
Package Tolerance
0.5%
1% 2%
TO-92 B431LAZ B431LBZ B431LCZ
SO-8 B431LAM
B431LBM
B431LCM
SOT-23 B431LAK3 B431LBK3 B431LCK3
Description
The B431L is a three terminal adjustable shunt regulator with
thermal stability of 50ppm/
C. The output voltage can be
adjusted to any value from 1.24V (V
REF
) to 16V with two
external resistors. These devices have a typical output
impedance of 0.05
. Active output circuitry provides a very
sharp turn-on characteristics and making the device excellent
replacement for zener diodes in many applications. The B431L
is an ideal voltage reference in an isolated feedback circuit for
3.0V switch mode power supplies
The B431L shunt regulator is available with three voltage
tolerances (0.5%, 1.0% and 2.0%) and three package options
(SOT-23-3, TO-92, 8SOIC). This allows the designer the
opportunity to select the optimum combination of cost and
performance for their application.
Features
Low voltage operation (down to 1.24V)
Wide operating current......80A to 100mA
Trimmed bandgap design.............. 0.5%
Low Dynamic Output Impedance.......0.05
Wide temperature range...... -40
C to +85
C
Available in ........SOT-23-3, TO-92 , 8SOIC
Pin-to-Pin Replacement ................SC431L
Applications
Switching Power Supplies
Adjustable Power Supplies
Linear Regulators
Battery Powered Equipment
Monitors, TV, VCR
Instrumentation
SOT-23-3 (K3)
Top View
BAY
Cathode
Anode
Ref
Bottom View
TO-92 (Z)
1
3
2
Ref
Anode
Cathode
SOT-23-3 (K3)
Top View
BAY
Cathode
Anode
Ref
Bottom View
TO-92 (Z)
1
3
2
Ref
Anode
Cathode
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Inspire the Linear Power
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Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
B431L
Absolute Maximum Rating
Recommended Operating Conditions
Min
Max
Symbol
Cathode Voltage, Vz
V
REF
16 V
Cathode Current, Iz
80A
100
mA
Electrical Characteristics
Unless specified: T
= 25
C
. Values in bold apply over full operating ambient temperature.
B431LA 0.5%
Parameter Symbol
Condition Min
Typ
Max
Units
1.234 1.246
Reference Voltage
V
REF
V
Z
= V
REF1
I
Z
= 10mA
(1)
1.222
1.240
1.258
V
V
REF
Temp Deviation
V
DEV
V
Z
= V
REF1,
I
Z
= 10mA
(1)
I
A
=full range
10 25
mV
Ratio of Change in
V
REF
To Change in V
Z
V
REF
V
Z
I
Z
= 10mA,V
Z
= 16V to V
Ref
(2)
-2.7 -1.0
mV/V
Reference Input
Current
I
REF
R1 = 10k
, R2 =
,
I
Z
= 10mA
(2)
0.15 0.5
A
I
REF
Temperature
Deviation
I
REF(DEV)
R1 = 10k
, R2 =
,
I
Z
= 10mA
(2)
0.1 0.4
A
V
REF
= 0V, V
Z
=16V
(3)
0.125
0.150
Off-State Cathode
Current
I
Z (OFF)
V
REF
= 0V, V
Z
=16V
(3)
0.135
0.150
A
Min Operating
Current
I
Z(MIN)
V
Z
= V
REF
(1)
20
80
A
Dynamic Impedance
Z
KA
V
KA
=V
ref
,
I
K
=100A to 100mA, f1kHA
0.05 0.15
Parameter Symbol
Maximum
Units
Cathode Voltage
V
z
20 V
Continuous Cathode Current
I
z
100
mA
Reference Input Current Range
3
mA
Power Dissipation at T
A
- 25
C
SOT-23-3
S0-8
TO-92
P
D
0.37
0.75
0.95
W
Thermal Resistance
SOT-23-3
S0-8
TO-92
O
JA
336
175
132
C/W
Operating Junction Temperature Range
T
J
-40 to +150
C
Storage Temperature Range
T
STG
-65 to +150
C
Lead Temperature (Soldering) 10 seconds
T
LEAD
300
C
ESD Rating (Human Body Model)
T
ESD
2 kV
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
B431L
Electrical Characteristics
Unless specified: T
= 25
C
. Values in bold apply over full operating ambient temperature.
B431LB 1%
Parameter Symbol
Condition Min
Typ
Max
Units
1.228 1.252
Reference Voltage
V
REF
V
Z
= V
REF1
I
Z
= 10mA
(1)
1.215
1.240
1.265
V
V
REF
Temp Deviation
V
DEV
V
Z
= V
REF1,
I
Z
= 10mA
(1)
I
A
=full range
10 25
mV
Ratio of Change in
V
REF
To Change in V
Z
V
REF
V
Z
I
Z
= 10mA,V
Z
= 16V to V
Ref
(2)
-1.0 -2.7
mV/V
Reference Input
Current
I
REF
R1 = 10k
, R2 =
,
I
Z
= 10mA
(2)
0.15 0.5
A
I
REF
Temperature
Deviation
I
REF(DEV)
R1 = 10k
, R2 =
,
I
Z
= 10mA
(2)
0.1 0.4
A
V
REF
= 0V, V
Z
=16V
(3)
0.125
0.150
Off-State Cathode
Current
I
Z (OFF)
V
REF
= 0V, V
Z
=16V
(3)
0.135
0.150
A
Min Operating
Current
I
Z(MIN)
V
Z
= V
REF
(1)
20
80
A
Dynamic Impedance
Z
KA
V
KA
=V
ref
,
I
K
=100A to 100mA, f1kHA
0.05 0.15
Electrical Characteristics
Unless specified: T
= 25
C
. Values in bold apply over full operating ambient temperature.
B431LC 2%
Parameter Symbol
Condition Min
Typ
Max
Units
1.215 1.265
Reference Voltage
V
REF
V
Z
= V
REF1
I
Z
= 10mA
(1)
1.200
1.240
1.280
V
V
REF
Temp Deviation
V
DEV
V
Z
= V
REF1,
I
Z
= 10mA
(1)
I
A
=full range
10 35
mV
Ratio of Change in
V
REF
To Change in V
Z
V
REF
V
Z
I
Z
= 10mA,V
Z
= 16V to V
Ref
(2)
-1.0 -2.7
mV/V
Reference Input
Current
I
REF
R1 = 10k
, R2 =
,
I
Z
= 10mA
(2)
0.15 0.5
A
I
REF
Temperature
Deviation
I
REF(DEV)
R1 = 10k
, R2 =
,
I
Z
= 10mA
(2)
0.1 0.4
A
V
REF
= 0V, V
Z
=16V
(3)
0.125
0.150
Off-State Cathode
Current
I
Z (OFF)
V
REF
= 0V, V
Z
=16V
(3)
0.135
0.150
A
Min Operating
Current
I
Z(MIN)
V
Z
= V
REF
(1)
20
80
A
Dynamic Impedance
Z
KA
V
KA
=V
ref
,
I
K
=100A to 100mA, f1kHA
0.05 0.15
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
B431L
Test Circuit: Small-Signal Gain & Phase
Test Circuit: Stability
43
1
431
L
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