Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 989-7144, Fax: (925) 940-9556 www.baylinear.com
3.0A Low Dropout Voltage Regulator
B1085
Adjustable
Pin Connection
Ordering Information
Devices Package Temp.
B1085T TO-220
0
C to 70
C
B1085S TO-263
0
C to 70
C
B1085D TO-252
0
C to 70
C
Description
The Bay Linear B1085 is Monolithic low power 3.0A
Adjustable and fixed NPN voltage regulator that are easy to
use with minimum external components. All internal circuitry
is designed to operate down to 1V input to output differential
and the dropout voltage is fully specified as a function of load
current. Dropout is guaranteed at a maximum of 1.5V at a
maximum output current. Current limit is trimmed, minimizing
the stress on both the regulator and power source circuitry
under overload conditions. It is suitable for applications
requiring a well-regulated positive output voltage with low
input-output differential voltage.
The B1085 Outstanding features include full power usage up
to 3.0Amp of load current internal current limiting and thermal
shutdown. A 10
F output capacitor is required on these new
devices; how ever, this is usually included in most regulator
design.
The B1085 is offered in a 3-pin TO-220, TO-263 & TO-252
packages compatible with other 3 terminal regulators. For 5A
Low dropout Regulator refer to the BL1084 data sheet.
Features
Adjustable Output Down to 1.2V
Output Current of 3.0A
Low Dropout Voltage 1.0V Typ.
0.015% Line Regulation
0.01% Load Regulation
Current & Thermal Limiting
Standard 3-Terminal Low Cost TO-220,
D
2
, D Packages
Similar to industry Standard LT1085
Applications
Constant Current Regulators
SMPS Post Regulator
High Efficiency Linear Regulator
High Efficiency Linear Power Supplies
Battery Charger
Adjustable Power Supplies
Bay Linear
Bay Linear
Bay Linear
Bay Linear
Linear Excellence
Front View
TO-252 (D)
ADJ/
GND
V
IN
V
OU
T
1
2
3
Top View
TO-263-3 (S)
1
Bay Linear
2
3
Top View
TO-263-3 (S)
1
Bay Linear
2
3
Top View
TO-263-3 (S)
1
Bay Linear
2
3
Top View
TO-263-3 (S)
1
Bay Linear
2
3
Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 989-7144, Fax: (925) 940-9556 www.baylinear.com
B1085
Absolute Maximum Rating
Parameter Symbol
Value
Unit
Maximum Input Voltage
V
IN
30 V
Power Dissipation
P
O
Internally Limited
W
Thermal Resistance Junction to Case
JC
3
Thermal Resistance Junction to
Ambient
JA
50
C/W
Operating Junction
Temperature Range
Control Section
Power Transistor
T
J
0 to 125
0 to 150
Storage Temperature Range
T
STG
-65 to 150
Lead Temperature (Soldering 10
Sec.)
T
LEAD
300
C
Electrical Characteristics
(V
IN
= 4.75V to 5.25V; I
O
= 10mA to 3.0Amp, unless otherwise specified)
Parameter Symbol
Conditions
MIN
TYP
MAX
UNIT
1.238 1.262
Reference Voltage
V
O
I
O
= 10mA,T= 25
C, V
in
-V
out
=3V
10mA
I
OUT
I
FULL LOAD
1.5V
(V
in
-V
out
)
25V (Note3)
1.225
1.250
1.270
V
Line Regulation (1)
REG
(line)
I
LOAD
= 10mA, 1.5V
(V
IN
V
OUT
)
15V
T= 25
C
15V
(V
in
-V
out
)
30V
0.015
0.035
0.05
0.20
0.20
0.50
Load Regulation (1)
REG
(LOAD)
(V
in
-V
out
)=3V
10mA
I
OUT
I
FULL LOAD
T= 25
C
0.1
0.2
0.30
0.40
%
Dropout Voltage
V
D
T= 25
C
Over Temperature
1.3
1.5 V
Current Limit
I
S
(V
in
-V
out
)=5V
(V
in
-V
out
)=25V
3.2
0.2
4
0.5
A
Minimum Load Current
I
MIN LOAD
(V
in
-V
out
)= 25V
10
10
mA
Temperature Regulation
T
A
T= 25
C, 30ms pulse
0.004
0.02
%/W
Long Term Stability
-
T= 25
C, 1000Hrs
0.3 1
Temperature Stability
T
S
0.5
%
Adjust pin Current
-
T= 25
C
Over Temp.
55
120
A
Ripple Rejection
R
A
F=120Hz, C
ADJ
=25
F, C
OUT
=25
F Tantalum
I
OUT
=I
FULL LOAD
, (V
in
-V
out
)=3V (Note 5)
60 75 dB
Thermal Resistance
-
TO-220 Junction to Tab
Junction to Ambient
DD Package Junction to Tab
Junction to Ambient
3.0
60
3.0
60
3.0
60
3.0
60
C/W
Note: Output Switch tests are performed under pulsed conditions to minimize power dissipation
Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 989-7144, Fax: (925) 940-9556 www.baylinear.com
Advance Information- These data sheets contain descriptions of products that are in development. The specifications are based on the engineering calculations,
computer simulations and/ or initial prototype evaluation.
Preliminary Information- These data sheets contain minimum and maximum specifications that are based on the initial device characterizations. These limits are
subject to change upon the completion of the full characterization over the specified temperature and supply voltage ranges.
The application circuit examples are only to explain the representative applications of the devices and are not intended to guarantee any circuit
design or permit any industrial property right to other rights to execute. Bay Linear takes no responsibility for any problems related to any
industrial property right resulting from the use of the contents shown in the data book. Typical parameters can and do vary in different
applications. Customer's technical experts must validate all operating parameters including " Typical" for each customer application.
LIFE SUPPORT AND NUCLEAR POLICY
Bay Linear products are not authorized for and should not be used within life support systems which are intended for surgical
implants into the body to support or sustain life, in aircraft, space equipment, submarine, or nuclear facility applications without
the specific written consent of Bay Linear President.
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