BL1085

BL1085
3A LOW DROPOUT LINEAR REGULATOR
Outline：
Features：
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 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℃
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.
Applications：
：
● Power Management for Computer
Pin Configuration：
：
● Battery Charger
● Post Regulators for Switching Supplies
● Microprocessor Supply
Mother Board, Graphic Card
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
Adjustable Version
Definition
Ground
Output
Input
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 (TJ)---------------------------------------------------------------------------- 150°C
Environment Temperature (TA) --------------------------------------------------------------------- 85°C
Storage Temperature (Ts)---------------------------------------------------------------------------- -65～150°C
Lead Temperature and Time ---------------------------------------------------------------------------------260°C,10S
Recommended Work Conditions：
：
Item
Min
Input Voltage Range
Environment Temperature
-40
Recommended
Max
Unit
18
85
V
°C
Electrical Characteristics (Table 1)：
：
Tj=25℃
Symbol
Vref
Vout
Parameter
Reference
Voltage
Output
Voltage
Conditions
Min
Typ
Max
Unit
Iout=10mA, Vin-Vout=3V
10mA≤Iout≤3A ,1.5V≤Vin-Vout≤5V
1.238
1.225
1.25
1.25
1.262
1.275
V
BL1085-1.80V
Iout=0mA,Vin=4.8V,Tj=25℃
10mA≤Iout≤3A ,3.4V≤Vin≤7V
1.782
1.764
1.80
1.80
1.818
1.836
2.475
2.45
2.50
2.50
2.525
2.55
BL1085-2.50V
Iout=0mA,Vin=4.8V,Tj=25℃
10mA≤Iout≤3A ,4.1V≤Vin≤7V
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V
V
1/29/2008
BL1085
∆Vout
∆Vout
Vin-Vout
Line
Regulation
(note 1)
Load
Regulation
(note 1,2)
BL1085-3.3V
Iout=0mA,Vin=6.3V,Tj=25℃
10mA ≤Iout≤3A ,4.9V≤Vin≤8V
3.267
3.234
3.3
3.3
3.333
3.366
V
BL1085-5.0V
Iout=0mA,Vin=8.0V,Tj=25℃
10mA ≤Iout≤3A ,6.6V≤Vin≤10V
4.95
4.90
5.0
5.0
5.05
5.10
V
BL1085-ADJ
Iout=10mA
2.85V≤Vin≤10V
0.035
0.2
%
BL1085-1.8V
Iout=10mA
3.4V≤Vin≤10V
10
15
mV
BL1085-2.5V
Iout=10mA
4.1V≤Vin≤10V
10
15
mV
BL1085-3.3V
Iout=10mA
4.9V≤Vin≤10V
10
15
mV
BL1085-5.0V
Iout=10mA
6.6V≤Vin≤10V
10
15
mV
BL1085-ADJ
Vin-Vout=3V, 10mA≤Iout≤3A
0.2
0.4
%
BL1085-1.8V
Vin-Vout=3V, 0≤Iout≤3A
3
15
mV
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
3
15
mV
1.3
1.5
V
Dropout
Voltage
(note 3)
∆Vout, ∆Vref =1%，Iout=3A
Current Limit
Vin-Vout=3V, Tj=25℃
Minimum
Load Current
(note 4)
BL1085-ADJ
3.2
4.5
A
Ilimit
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10
mA
1/29/2008
BL1085
Iq
IAdj
Quiescent
Current
Adjust Pin
Current
(Adjustable
Version)
Ripple
Rejection
Ichange
θ JC
Vin=10V
4
10
mA
Vin=4.25V,
Iout=10mA
45
110
uA
F=120Hz,Cout=25uF( tan),
Iout=3A,Vin-Vout=3V
Adjust Pin
Current
Change
10mA≤Iout≤3A
1.5V≤Vin-Vout ≤6V
Temperature
Stability
Iout=10mA,
Vin-Vout=1.5V
Thermal
Resistance
junction to case
60
dB
0.2
TO-252
TO-263
TO-220
12.5
3
3
5
uA
0.5
%
℃/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℃≤TA≤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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BL1085
Typical Application ：
BL1085 has an adjustable version and fixed versions, Chart1 is its typical application：
Typical Application of BL1085
Application Hints：
1. Recommend using 10uF tan capacitor as bypass capacitor for all application circuit.
2. Recommend using 22uF tan capacitor to assure circuit stability.
3. Using a bypass capacitor(CAdj) between the adjust terminal and ground can improve ripple
rejection, This bypass capacitor prevents ripple from being amplified as the output voltage is
increased. The impedance of CAdj should be less than the resistor’s(R1) which is between output and
adjust pins to prevent ripple from being amplified at any ripple frequency. As R1 is normally in the
range of 120Ω~200Ω,the value of CAdj should satisfy this equation: 2*Fripple*CAdj<R1. Recommend
using 10uF tan capacitor.
Output Voltage of Adjustable Version：
The BL1085 adjustable version provide 1.25V Reference Voltage. Any output voltage between
1.25V~13.8V can be available by choosing two external resistors (connection method is shown in
chart 1). In chart 1, R1,R2 is the two external resistors.
Explanation ：
The output voltage of adjustable version satisfies this followed equation:
VOut=VRef*(1+R2/R1)+IAdj*R2. We can ignore IAdj because IAdj(about 50uA) is much less
than the current of R1(about 4mA).
How to choose R1：The value of R1 should be in the range of 120Ω～200Ω to assure chip
working normally without any load. To assure the electrical performance showed in table 1, the output
current should be larger than 5mA. If R1 is too large, the minimum output current should be larger
than 4mA , The best working condition is to assure that the output current exceeds 10mA.
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BL1085
：
Typical Performance Characteristics：
Reference Voltage VS.Temperature
1.50
1.45
1.40
1.35
1.30
1.25
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
1.28
1.27
1.26
Vref(V)
Dropout (V)
Dropout Voltage VS.Output Current
1.25
1.24
1.23
1.22
1.21
1.20
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0
20
40
60
1.25
1.20
Vout(V)
Vref(V)
1.15
Iout=1A
1.00
0.95
0.90
20
40
60
80
100
T(oC)
120
Output Voltage VS. Output Current
Reference Voltage VS. Thermal Protection
1.05
100
T(oC)
Iout(A)
1.10
80
120
140
1.25
1.2
1.15
1.1
1.05
1
0.95
0.9
0.85
0.8
160
Vin=2.55
0
0.5
1
1.5
2
2.5
Iout(A)
3
3.5
4
Line Transient Response
Load Transient Response
3A
Vin
0.1A
Vout
Vout
CH1 1.5A
Vin=4.25V
CH2 100mV
Vout=1.25V
CH1 1.0V
CH2 20.0mV
M 250us
Vin=3.25V to 5.25V Vout=1.25V
Iout=200mA
Cin=1uF (tan) Cout=10uF(tan)
M 100us
Iout=100mA to 3A
Cin=Cout=10uF(tan)
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BL1085
Package outline:
1.TO-252
Package
TO-252
Devices per
reel
2500
Unit
mm
Package specification：
Taping dimension：（M1：Standard Type ，M2：Customized）
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BL1085
Taping reel dimension：
2.TO-220
Package
TO-220
Devices per
tube
50
Unit
mm
Package specification：
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BL1085
Tube dimension：
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BL1085
3.TO-263-2L
Package
TO-263
Devices per
reel
800
Unit
mm
Package specification：
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BL1085
Taping dimension：
Taping reel dimension：
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BL1085
4.TO-263-3L
Package
TO-263
Devices per
reel
800
Unit
mm
Package specification：
Taping dimension：
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BL1085
Taping reel dimension：
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