BL1085
3A LOW DROPOUT LINEAR REGULATOR
Outline：
BL1085 is a series of low dropout three
terminal regulators with a dropout of 1.3V at
3A load current.
Other than a fixed version (Vout
＝
1.8V,2.5V,3.3V,5.0V
）
, BL1085 has an
adjustable version, The adjustable version can
set the output voltage with two external
resistors.
BL1085 offers thermal shut down and current
limit functions, to assure the stability
of chip and power system. And it uses
trimming technique to guarantee output
voltage accuracy within
±2％.
The BL1085 series is available in standard
packages of TO-263-2L, TO-263-3L, TO-220
and TO-252.
Features：
●
Other than a fixed version and an
adjustable version, output value can be
customized on command.
●
Maximum output current is 3A
●
Output voltage accuracy is within
±2％
（±1％
Customized）
●
Range of operation input voltage: Max
18V
●
Line regulation: 0.2％ (Typical)
●
Load regulation: 0.2％ (Typical)
●
Environment Temperature: -40℃~85℃
Applications：
：
●
Power Management for Computer
Mother Board, Graphic Card
●
Battery Charger
●
Post Regulators for Switching Supplies
●
Microprocessor Supply
Pin Configuration：
：
Marking
information：
：
A：
Means
Manufacture
weeks
B：
Means
Manufacture LOT
No.
C:
Means Output
Voltage Value
D:
Means Temp.
Range&Rohs Std
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BL1085
：
Pin Description：
Fixed Version
Pin No.
1
2
3
Symbol
GND
Vout
Vin
Definition
Ground
Output
Input
Adjustable Version
Pin No.
1
2
3
Symbol Definition
Adj.
Adjustable
Vout
Output
Vin
Input
Ordering Information:
BL1085-XX
X X
Package Type：
：
S：TO-263-2L
S1：TO-263-3L
Y：TO-252
Z：TO-220
Temp. Range & Rohs Std.：
：
C：140C & Pb-free Rhos Std
Z：140C & Pb/Sn Plating
Output Voltage：
：
18……1.8V
25……2.5V
33……3.3V
50……5.0V
Default：Adjustable
Version
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BL1085
Block Diagrams：
：
Absolute Maximum Ratings：
：
Maximum Input Voltage------------------------------------------------------------------------------- 18V
Junction Temperature (T
J
)---------------------------------------------------------------------------- 150°C
Environment Temperature (T
A
) --------------------------------------------------------------------- 85°C
Storage Temperature (Ts)---------------------------------------------------------------------------- -65½150°C
Lead Temperature and Time
---------------------------------------------------------------------------------
260°C,10S
Recommended Work Conditions：
：
Item
Input Voltage Range
Environment Temperature
Min
-40
Recommended
Max
18
85
Unit
V
°C
Electrical Characteristics (Table 1)：
：
Tj=25℃
Symbol
Vref
Vout
Parameter
Reference
Voltage
Output
Voltage
Conditions
Iout=10mA, Vin-Vout=3V
10mA≤Iout≤3A ,1.5V≤Vin-Vout≤5V
BL1085-1.80V
Iout=0mA,Vin=4.8V,Tj=25℃
10mA≤Iout≤3A ,3.4V≤Vin≤7V
BL1085-2.50V
Iout=0mA,Vin=4.8V,Tj=25℃
10mA≤Iout≤3A ,4.1V≤Vin≤7V
Min
1.238
1.225
Typ
1.25
1.25
Max
1.262
1.275
Unit
V
1.782
1.764
2.475
2.45
1.80
1.80
2.50
2.50
1.818
1.836
2.525
2.55
V
V
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BL1085
BL1085-3.3V
Iout=0mA,Vin=6.3V,Tj=25℃
10mA
≤Iout≤3A
,4.9V≤Vin≤8V
BL1085-5.0V
Iout=0mA,Vin=8.0V,Tj=25℃
10mA
≤Iout≤3A
,6.6V≤Vin≤10V
BL1085-ADJ
Iout=10mA
2.85V≤Vin≤10V
BL1085-1.8V
Iout=10mA
3.4V≤Vin≤10V
Line
Regulation
(note 1)
BL1085-2.5V
Iout=10mA
4.1V≤Vin≤10V
BL1085-3.3V
Iout=10mA
4.9V≤Vin≤10V
BL1085-5.0V
Iout=10mA
6.6V≤Vin≤10V
BL1085-ADJ
Vin-Vout=3V, 10mA≤Iout≤3A
3.267
3.234
3.3
3.3
3.333
3.366
V
4.95
4.90
5.0
5.0
5.05
5.10
V
0.035
0.2
%
10
15
mV
∆Vout
10
15
mV
10
15
mV
10
15
mV
0.2
0.4
%
BL1085-1.8V
Vin-Vout=3V, 0≤Iout≤3A
Load
Regulation
(note 1,2)
3
15
mV
∆Vout
BL1085-2.5V
Vin-Vout=3V, 0≤Iout≤3A
3
15
mV
BL1085-3.3V
Vin-Vout=3V, 0≤Iout≤3A
3
15
mV
BL1085-5.0V
Vin-Vout=3V, 0≤Iout≤3A
Dropout
Voltage
(note 3)
3
15
mV
Vin-Vout
∆Vout, ∆Vref
=1%，Iout=3A
1.3
1.5
V
Current Limit
Ilimit
Minimum
Load Current
(note 4)
Vin-Vout=3V, Tj=25℃
3.2
4.5
A
BL1085-ADJ
3
10
mA
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BL1085
Iq
Quiescent
Current
Adjust Pin
Current
(Adjustable
Version)
Vin=10V
4
10
mA
IAdj
Vin=4.25V,
Iout=10mA
45
110
uA
Ripple
Rejection
Adjust Pin
Current
Change
Temperature
Stability
Thermal
Resistance
junction to case
F=120Hz,Cout=25uF( tan),
Iout=3A,Vin-Vout=3V
60
dB
Ichange
10mA≤Iout≤3A
1.5V≤Vin-Vout
≤6V
0.2
5
uA
Iout=10mA,
Vin-Vout=1.5V
TO-252
TO-263
TO-220
12.5
3
3
0.5
%
θ
JC
℃
/W
Note:
Note1：The Parameters of Line Regulation and Load Regulation in Table1 are tested under
constant junction temperature.
Note2： When Iout varies between 0~3A,Vin-Vout varies between 1.5V~6V under constant
junction temperature，the parameter is satisfied the criterion in table. If temperature
varies between -40℃≤T
A
≤85℃，it
needs output current to be larger than 10mA to
satisfy the criterion.
Note3：Dropout Voltage is tested under Iout=3A and the following testing conditions: First step
is to find out the Vout value(Vout1) when Vin1=Vout+1.5V, second step is to decrease
Vin(Vin2) until Vout value is equal to 99%*Vout1(Vout2). Vdropout=Vin2-Vout2.
Note4：Minimum Load Current is defined as the minimum output current required to maintain
regulation. When 1.5V≦Vin-Vout≦6V，the device is guaranteed to regulate if the
output current is greater than 10mA.
Detailed Description:
BL1085 is a series of low dropout voltage, three terminal regulators. Its application circuit is very
simple: the fixed version only needs two capacitors and the adjustable version only needs two
resistors and two capacitors to work. It is composed of some modules including start-up circuit, bias
circuit, bandgap, thermal shutdown, current limit, power transistors and its driver circuit and so on.
The thermal shut down and current limit modules can assure chip and its application system
working safety when the environment temperature is larger than 85℃ or output current is larger than
3.2A.
The bandgap module provides stable reference voltage, whose temperature coefficient is
compensated by careful design considerations. The temperature coefficient is under 100ppm/℃.
And the accuracy of output voltage is guaranteed by trimming technique.
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