Bay Linear
Inspire the Linear Power
1.0Amp Low Dropout Voltage Regulator
Adjustable & Fix (0.40Volt Dropout)
B1117
Description
The Bay Linear B1117 is a three terminal positive NPN
regulator offered as adjustable or fix voltages of 1.5V,1.8V,
2.5V, 2.85V, 3.3V, and 5Volts. The output current has a
capability up to
1.0Amp,
. This device has been optimized for
low voltage where transient response and minimum input
voltage are critical. The 2.85V version is designed specifically
to be used in active terminators for SCSI bus.
Current limit is trimmed to ensure specified output current and
controlled short-circuit current. On-Chip thermal limiting
provides protection against any combination of overload and
ambient temperatures that would create excessive junction
temperatures.
The B1117 is offered in a 3-pin SOT-223, and TO-252
(DPAK) packages compatible with other 3 terminal regulators.
5-pin version in TO-263 with lower dropout of 0.4 volt is
available.
Features
•
•
•
•
•
•
•
•
•
Adjustable Output Down to 1.2V
Output Current of 1.0Amp
Low Dropout 1.0V for B1117
Dropout of 0.40 V in for B1117A
Adjustable & Fix 1.5V, 1.8V, 2.5V, 2.85V,
3.0V, 3.3V, 5.0V
0.05% Load Regulation
Current & Thermal Limiting
Lower Cost SOT-89 Package
Available in SOT-223, and TO-252,
TO-263 & SO-8
Similar to industry Standard LT1117
•
Applications
•
•
•
•
•
•
Active SCSI terminators
High efficiency Linear Regulator
Post regulators fro Switching Supplies
Battery Charger
5V to 3.3V linear Regulators
Motherboard Clock Supplies
Pin Connection
Ordering Information
Devices
B1117D-X
B1117N-X
B1117T-X
B1117S-X
B1117M-X
Package
TO-252
TO-223
TO-220
TO-263
SO-8
Temp.
0
°C
to 125
°C
0
°C
to 125
°C
0
°C
to 125
°C
0
°C
to 125
°C
0
°C
to 125
°C
8-Pin Surface Mount
ADJ
NC
OUT
OUT
1
2
3
4
8
7
6
5
IN
IN
SOT -223
Tab V
OUT
SOT-223-5
SOT-223
Tab V
OUT
IN
N.C.
#1 Sense
#2 Adj/GND
#3 OUT
#4 Control
#5 V
IN
5
TO-252
5
4
3
2
1
V
POWER
V
CONTROL
OUTPUT
ADJ/GND.
SENSE
Top View
Adj/GND OUT IN
Front View
1
2
3
4
Front View
1
2
3
TO-263-5 Package
ADJ/GN V
OUT
V
IN
Front
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1117
Absolute Maximum Rating
Parameter
Maximum Input Voltage
Operating Junction Temperature Range
Storage Temperature Range
Lead Temperature (Soldering 10 Sec.)
Min
0
-65
Max
7.0
125
150
300
Unit
V
°C
Electrical Characteristics
(V
IN
= 7V; T
J
=25
°C
I
O
= 10mA to 1.0Amp, unless otherwise specified)
Parameter
Symbol
Conditions
Reference Voltage
V
O
1117-adj,
I
OUT
=10mA, V
IN
-V
OUT
=2V, T
J
=25°C
1.5V≤(V
IN
-V
OUT
)
≤5.75V
10mA≤I
OUT
≤I
FULL LOAD
(V
OUT
+1.5)≤V
IN
≤7V,
I
OUT
=10mA
MIN
1.238
1.225
-2%
TYP
1.250
1.250
0.005
MAX
1.262
1.275
+2%
0.2
UNIT
V
V
%
Line Regulation (1)
REG
(line)
Load Regulation (1)
REG
(LOAD)
Output Voltage
V
O
(V
in
-V
out
)=2V
10mA≤I
OUT
≤I
FULL LOAD
T= 25
°C
1117-1.8 I
OUT
=10mA, V
IN
=3.8V, T
J
=25°C
0≤I
OUT
≤1.0Amp,
3.2V≤V
IN
≤7V
1117-2.5 I
OUT
=10mA, V
IN
=4.5V, T
J
=25°C
0≤I
OUT
≤1.0Amp,
4.0V≤V
IN
≤7V
1117-2.85 I
OUT
=10mA, V
IN
=4.85V, T
J
=25°C
0≤I
OUT
≤1.0Amp,
4.35V≤V
IN
≤7V
1117-3.3 I
OUT
=10mA, V
IN
=5.0V, T
J
=25°C
0≤I
OUT
≤1.0Amp,
4.8V≤V
IN
≤7V
1117-5.0 I
OUT
=10mA, V
IN
=6.0V, T
J
=25°C
0≤I
OUT
≤1.0Amp,
6.5V≤V
IN
≤7V
Control Input
V
POWER
=V
OUT
+0.8, I
LOAD
=10mA
V
POWER
=V
OUT
+0.8, I
LOAD
=
1.0Amp,
Power Input
V
CONTROL
=V
OUT
-+2.5V, I
LOAD
=
1.0Amp,
(V
in
-V
out
)=2V
1.5V≤(V
IN
-V
OUT
)
≤5.75V
T= 25
°C,
30ms pulse
T= 25
°C,
1000Hrs
T= 25
°C
F=120Hz, C
ADJ
=22µF, C
OUT
=22µF Tantalum
I
OUT
=I
FULL LOAD
, (V
in
-V
out
)=3V (Note 5)
0.05
0.5
1.782
1.746
2.475
2.450
2.820
2.790
3.267
3.235
4.950
4.900
1.80
1.80
2.50
2.50
2.85
2.85
3.30
3.30
5.00
5.00
0.80
0.80
0.35
1.818
1.854
2.525
2.550
2.880
2.910
3.333
3.365
5.050
5.100
1.00
1.10
0.40
V
V
V
V
V
Dropout Voltage
V
D
V
D
I
S
I
MIN LOAD
T
A
-
T
S
-
R
A
V
V
A
mA
%/W
%
%
µA
dB
°C
°C
Dropout Voltage
Current Limit
Minimum Load Current
Temperature Regulation
Long Term Stability
Temperature Stability
Adjust pin Current
Ripple Rejection
Thermal Shutdown
Thermal Shutdown
Hysterics
1.0
10
1.1
60
0.004
0.03
0.5
35
75
155
10
0.02
1.0
120
-
Thermal Resistance
Junction to case
SOT-223
DD Package
15
3.0
15
3.0
°C/W
Note:
Output Switch tests are performed under pulsed conditions to minimize power dissipation
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1117
TYPICAL CHRACTRISTICS
B1117-2.85
B1117-ADJ
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1117
TYPICAL CHRACTRISTICS (Continued)
B1117-2.85
B1117-5.0
B1117-2.85
B1117-5.0 Line Transient Response
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1117
APPLICATION NOTES EXTERNAL
CAPACITOR
To ensure the stability of the B1117 an output capacitor of at
least 10µF (tantalum)or 50µF (aluminum) is required. The
value may change based on the application requirements on
the output load or temperature range. The capacitor
equivalent series resistance (ESR) will effect the B1117
stability. The value of ESR can vary from the type of
capacitor used in the applications. The recommended value
for ESR is 0.5Ω. The output capacitance could increase in
size to above the minimum value. The larger value of
output capacitance as high as 100µF can improve the load
transient response.
Maximum Junction Temperature range:
T
J
= T
ambient
(max) + P
D
* thermal resistance (Junction-to-
ambient)
Maximum Junction temperature must not exceed the
125°C.
10V
SOLDERING METHODS
The B1117 SOT-223 package is designed to be compatible
with infrared reflow or vapor-phase reflow soldering
techniques. During soldering the non-active or mildly active
fluxes may be used. The B1117 die is attached to the heat
sink lead which exits opposite the input, output, and ground
pins.
Hand soldering and wave soldering should be avoided since
these methods can cause damage to the device with
excessive thermal gradients on the package. The SOT-223
recommended soldering method are as follows: vapor phase
reflow and infrared reflow with the component preheated to
within 65°C of the soldering temperature range.
+
2.85V
B1117-2.85
+
10uF
10uF
27K
..
Ω
P
O
= (10V - 2.85)(105mA) = (7.15)(105mA) = 750mW
Fig. 1. Circuit Layout, Thermal Experiments.
THERMAL CHARACTERISTICS
The thermal resistance of B1117 is 15°C/W from junction to
tab and 31
°C/W
from tab to ambient for a total of 46
°C/W
from junction to ambient. The B1117 features the internal
thermal limiting to protect the device during overload
conditions. Special care needs to be taken during continues
load conditions the maximum junction temperature does not
exceed 125
°C.
Taking the FR-4 printed circuit board and 1/16 thick with 1
ounce copper foil as an experiment (fig.1 & fig.2), the PCB
material is effective at transmitting heat with the tab
attached to the pad area and a ground plane layer on the
backside of the substrate. Refer to table 1 for the results of
the experiment.
The thermal interaction from other components in the
application can effect the thermal resistance of the B1117.
The actual thermal resistance can be determined with
experimentation. B1117 power dissipation is calculated as
follows:
P
D
= (V
IN
- V
OUT
)(I
OUT
)
50 X 50 mm
35 X 17 mm
16 X 10 mm
Fig. 2. Substrate Layout for SOT-223
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
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