1
3A Adjustable Low Dropout
Linear Regulator (LDO)
NIKO-SEM
L1085
TO-252,263,220
MAY-31-2001
GENERAL DESCRIPTION
The L1085 is a positive and low dropout
three-terminal voltage regulator with 3A out-
put current capability. This device is design-
ed for use in low voltage applications that
offers lower dropout voltage and faster tran-
sient response.
This device is fully protected against over
current faults, over temperature operation,
reversed input polarity, reversed lead insert-
ion, transient voltage spike ...etc.
On-Chips trimming the reference voltage to
1% and features the low dropout of maxi-
mum 1.45 volts.
The L1085 Series regulators are available
in the popular industry standard TO-220
TO-263 and TO-252 packages.
FEATURES
Very easy to use, it requires only two
external resistors to set the output voltage
Low dropout voltage:
1.3V typical at up to 3A
Low ground current
Fast transient response
Current & thermal limiting
Line regulation: 0.5% typical
Load regulation: 0.5% typical
TO-220, TO-263 and TO-252 packages
APPLICATIONS
High current microprocessor supplies
Low voltage logic supply
Powering VGA & sound card
Portable instrumentation
Constant current regulator
Post regulator for switching power supply
TYPICAL APPLICATION
- Basic Adjustable Regulator Circuit -
+
Cin
10uF
R2
+
Cout
10uF
R1
IN
ADJ
OUT
L1085
Vin
1. Cin needed if device is far from from filter capacitors.
Iadj
Vo = Vref (1+R2/R1) + Iadj x R2
Vout
Vref
2. Cout required for stability.
2
3A Adjustable Low Dropout
Linear Regulator (LDO)
NIKO-SEM
L1085
TO-252,263,220
MAY-31-2001
ABSOLUTE MAXIMUM RATINGS
Maximum Supply Voltage
7V
Operating Junction
Temperature Range
0 to 125 C
Power Dissipation
Internally
Limited
Storage Temperature
Range
-40 to 150 C
Thermal Resistance
Junction to Case,
JC
5 C/W
Lead Temperature
(Soldering, 10 Seconds)
260 C
Thermal Resistance
Junction to Ambient,
JA
TO-263
TO-252
TO-220
60 C/W
70 C/W
50 C/W
ELECTRICAL CHARACTERISTICS (
Unless otherwise specified, T
A
= 25 C.)
Parameter
Symbol
Test Conditions
Typical
Limits
Reference Voltage
V
REF
V
IN
= 5V, I
OUT
= 10mA
1.25V
1.23V
Min
1.27V
Max
Dropout Voltage
V
D
V
REF
= 1%, I
OUT
= 3A
1.3V 1.45V
Line Regulation
REG
(LINE)
(V
OUT
+ 1.5V)
V
IN
7V, I
OUT
= 10mA
0.5% 2%
Load Regulation
REG
(LOAD)
(V
IN
-V
OUT
) = 3V, 10mA
I
OUT
3A
0.5% 2.5%
Minimum Load
Current
I
O
1.5V
(V
IN
-V
OUT
)
5.75V
10mA
Adjust Pin Current
I
ADJ
55
A 100
A
Current Limit
I
CL
V
IN
- V
OUT
= 2V
5.0A
4.0A (Min)
RMS Output Noise
V
N
0.003%
of V
OUT
Ripple Rejection
Ratio
R
A
f = 120Hz, C
ADJ
= 22
F for ADJ pin,
V
IN
= 5V, I
OUT
= 3A
72dB 60dB
(Min)
DEVICE SELECTION GUIDE
Device
L1085D L1085S L1085S3 L1085T
Package
TO-252
TO-263 (2-Lead) TO-263 (3-Lead)
TO-220
Marking
L1085D L1085S L1085S3 L1085T
4
3A Adjustable Low Dropout
Linear Regulator (LDO)
NIKO-SEM
L1085
TO-252,263,220
MAY-31-2001
TO-263 (D
2
PAK) MECHANICAL DATA
mm
mm
Dimension
Min. Typ. Max.
Dimension
Min. Typ. Max.
A 14.5 15 15.8 H 1.0 1.5 1.8
B 4.2 4.7 I 9.8 10.3
C
1.20 1.35 J 6.5
D 2.8 K 1.5
E 0.3 0.4 0.5 L 0.7 1.4
F -0.102 0.203 M 4.83 5.08 5.33
G
8.5
9
9.5
N
5
3A Adjustable Low Dropout
Linear Regulator (LDO)
NIKO-SEM
L1085
TO-252,263,220
MAY-31-2001
TO-263 (D
2
PAK) MECHANICAL DATA
mm
mm
Dimension
Min. Typ. Max.
Dimension
Min. Typ. Max.
A 14.5 15 15.8 H 1.0 1.5 1.8
B 4.2 4.7 I 9.8 10.3
C
1.20 1.35 J 6.5
D 2.8 K 1.5
E 0.3 0.4 0.5 L 0.7 1.4
F -0.102 0.203 M 4.83 5.08 5.33
G
8.5
9
9.5
N
6
3A Adjustable Low Dropout
Linear Regulator (LDO)
NIKO-SEM
L1085
TO-252,263,220
MAY-31-2001
TO-220 (3-Lead) MECHANICAL DATA
mm
mm
Dimension
Min. Typ. Max.
Dimension
Min. Typ. Max.
A 9.78
10.16
10.54 H 2.4 2.54
2.68
B 2.61 2.74 2.87 I 1.19 1.27 1.35
C 20
J 4.4 4.6 4.8
D 28.5 28.9 29.3 K 1.14 1.27 1.4
E 14.6
15.0
15.4 L 2.3 2.6 2.9
F 8.4 8.8 9.2 M 0.26 0.46 0.66
G 0.72 0.8 0.88 N 7
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