Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94506 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
The Electrical Grade & Type is specified on shipping Box Only
2.5V Adjustable Shunt Regulator
B431
Package Information
Ordering Information
Bottom View
TO-92 (Z)
1
3
2
Ref
Anode Cath
Top View
2
1
3
4
8
7
6
5
8-Pin Surface Mount (M)
Package
Tolerance
0.5%
1%
1%
2%
TO-92
B431AZ B431BZ B431DBZ B431CZ
SOT-89
B431AR B431BR B431DBR B431CR
8SOIC
B431AM B431BM B431DBM B431CM
Description
The Bay Linear B431 is a three terminal adjustable shunt
regulator with thermal stability over Temperature range. Using
two external resistors allows the output voltage to be adjusted
from 2.5V to 36V. With a sharp turn on characteristics the
B431 a superior replacement for zener diode applications.
The B431 shunt regulator has a tolerance of 0.5% which has
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 manufacturers assembly line and contribute a
significant cost savings.
Features
Wide Operating Range ...1mA to100mA
Tight Band Gap Tolerance .......... 0.5%
Low Temp. Coefficient...........30 ppm/
o
C
Wide temp range of 40 to +105
o
C
Available in TO92, SOT-89, SO-8
Applications
Switching Power Supplies
Adjustable Power Supplies
Linear Regulators
Battery Powered Equipment
Monitors, TV, VCR
Instrumentation
Bay Linear
Inspire the Linear Power
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94506 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
B431
Absolute Max Ratings
Recommended Operating Conditions
Min Max
Symbol
Cathode Voltage, Vz
V
REF
36 V
Cathode Current, Iz
0.1
100
mA
Electrical Characteristics
Unless specified: T
= 25
C
. Values in bold apply over full operating ambient temperature.
B431 0.5%
Parameter Symbol
Condition Min
Typ
Max
Units
Reference Voltage
V
REF
V
Z
= V
REF1
I
Z
= 10mA
(1)
2.483 2.495 2.507
V
V
REF
Temp Deviation
V
DEV
V
Z
= V
REF1
I
Z
= 10mA
(1)
4 17 mV
I
Z
= 10mA,V
Z
= 10V to V
Ref
-1.0 -2.7
Ratio of Change in
V
REF
To Change in V
Z
V
REF
V
Z
I
Z
= 10mA,V
Z
= 36V to 10V
-0.4 -2.0
mV/V
Reference Input
Current
IREF
R1 = 10k
, R2 = ,
I
Z
= 10mA
(2)
0.7 4
A
I
REF
Temperature
Deviation
I
REF(DEV)
R1 = 10k
, R2 = ,
I
Z
= 10mA
(2)
0.4 1.2
A
Off-State Cathode
Current
I
Z (OFF)
V
REF
= 0V, V
Z
=36V
(3)
0.1 1
A
Dynamic Output
Impedance
rz
F <1kHz, V
Z
= V
REF
I
Z
= 1mA to 100mA
(1)
0.20 0.50
Minimum Operating
Current
I
Z(MIN)
V
Z
= V
REF
(1)
0.4
1
mA
Parameter Symbol
Maximum
Units
Cathode Voltage
V
z
37 V
Continuous Cathode Current
I
z
150
mA
Reference Input Current
I
REF
10 mA
Power Dissipation at T
A
- 25
C
SOT-89
S0-8
TO-92
P
D
1000
750
775
mW
Thermal Resistance
S0-8
TO-92
SOT-89
O
JA
175
160
110
C/W
Operating Junction Temperature Range
T
J
-40 to +150
C
Operating Ambient Temperature
T
A
-40 to +105
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 94506 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
B431
B431 1%
Parameter Symbol
Condition Min
Typ
Max
Units
Reference Voltage
V
REF
V
Z
= V
REF1
I
Z
= 10mA
(1)
2.470 2.495 2.520
V
V
REF
Temp Deviation
V
DEV
V
Z
= V
REF1
I
Z
= 10mA
(1)
4 17 mV
I
Z
= 10mA,V
Z
= 10V to V
Ref
-1.0 -2.7
Ratio of Change in
V
REF
To Change in V
Z
V
REF
V
Z
I
Z
= 10mA,V
Z
= 36V to 10V
-0.4 -2.0
mV/V
Reference Input
Current
IREF
R1 = 10k
, R2 = ,
I
Z
= 10mA
(2)
0.7 4
A
I
REF
Temperature
Deviation
I
REF(DEV)
R1 = 10k
, R2 = ,
I
Z
= 10mA
(2)
0.4 1.2
A
Off-State Cathode
Current
I
Z (OFF)
V
REF
= 0V, V
Z
=36V
(3)
0.1 1
A
Dynamic Output
Impedance
rz
F <1kHz, V
Z
= V
REF
I
Z
= 1mA to 100mA
(1)
0.20 0.50
Minimum Operating
Current
I
Z(MIN)
V
Z
= V
REF
(1)
0.4
1
mA
B431 2%
Parameter Symbol
Condition Min
Typ
Max
Units
Reference Voltage
V
REF
V
Z
= V
REF1
I
Z
= 10mA
(1)
2.445 2.495 2.545
V
V
REF
Temp Deviation
V
DEV
V
Z
= V
REF1
I
Z
= 10mA
(1)
4 17 mV
I
Z
= 10mA,V
Z
= 10V to V
Ref
-1.0 -2.7
Ratio of Change in
V
REF
To Change in V
Z
V
REF
V
Z
I
Z
= 10mA,V
Z
= 36V to 10V
-0.4 -2.0
mV/V
Reference Input
Current
IREF
R1 = 10k
, R2 = ,
I
Z
= 10mA
(2)
0.7 4
A
I
REF
Temperature
Deviation
I
REF(DEV)
R1 = 10k
, R2 = ,
I
Z
= 10mA
(2)
0.4 1.2
A
Off-State Cathode
Current
I
Z (OFF)
V
REF
= 0V, V
Z
=36V
(3)
0.1 1
A
Dynamic Output
Impedance
rz
F <1kHz, V
Z
= V
REF
I
Z
= 1mA to 100mA
(1)
0.20 0.50
Minimum Operating
Current
I
Z(MIN)
V
Z
= V
REF
(1)
0.4
1
mA
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94506 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
B431
B431D 1%
Parameter Symbol
Condition Min
Typ
Max
Units
Reference Voltage
V
REF
V
Z
= V
REF1
I
Z
= 10mA
(1)
2.470 2.495 2.520
V
V
REF
Temp Deviation
V
DEV
V
Z
= V
REF1
I
Z
= 10mA
(1)
4 17 mV
I
Z
= 10mA,V
Z
= 10V to V
Ref
-1.0 -2.7
Ratio of Change in
V
REF
To Change in V
Z
V
REF
V
Z
I
Z
= 10mA,V
Z
= 36V to 10V
-0.4 -2.0
mV/V
Reference Input
Current
IREF
R1 = 10k
, R2 = ,
I
Z
= 10mA
(2)
0.7 4
A
I
REF
Temperature
Deviation
I
REF(DEV)
R1 = 10k
, R2 = ,
I
Z
= 10mA
(2)
0.4 1.2
A
Off-State Cathode
Current
I
Z (OFF)
V
REF
= 0V, V
Z
=36V
(3)
0.1 1
A
Dynamic Output
Impedance
rz
F <1kHz, V
Z
= V
REF
I
Z
= 1mA to 100mA
(1)
0.20 0.50
Minimum Operating
Current
I
Z(MIN)
V
Z
= V
REF
(1)
0.4
1
mA
Note 1: B431D is rated at -40
C to +85C and 50ppm/C
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94506 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
B431
Calculating Average Temperature Coefficient (TC)
Test Circuit
ppm
mV
TC in mV/C =
V
REF
(mV)
T
A
TC in %/C =
V
REF
at 25C
T
A
V
REF
)
)
x 100
TC in ppm/C =
V
REF
at 25C
T
A
V
REF
)
)
x 10
6
5000
-55
0.06 mV/C
V
REF
0
0
0
%
-20
-10
0.5
Temperature (C)
0.002 %/C
24 ppm/C
-25
0
25
50
75 100 125
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
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