1/19
March 2005
I
TYPICAL DROPOUT 1.3V (AT 3A)
I
THREE TERMINAL ADJUSTABLE OR FIXED
OUTPUT VOLTAGE 1.5V, 1.8V, 2.5V, 2.85V,
3.3V, 3.6V, 5V, 8V, 9V, 12V.
I
GUARANTEED OUTPUT CURRENT UP TO
3A
I
OUPUT TOLERANCE
1% AT 25C AND
2% IN FULL TEMPERATURE RANGE
I
INTERNAL POWER AND THERMAL LIMIT
I
WIDE OPERATING TEMPERATURE RANGE
-40C TO 125C
I
PACKAGE AVAILABLE: TO-220, TO-220FP
D
2
PAK, D
2
PAK/A
I
PINOUT COMPATIBILITY WITH STANDARD
ADJUSTABLE VREG
DESCRIPTION
The LD1085 is a LOW DROP Voltage Regulator
able to provide up to 3A of Output Current.
Dropout is guaranteed at a maximum of 1.2V at
the maximum output current, decreasing at lower
loads. The LD1085 is pin to pin compatible with
the older 3-terminal adjustable regulators, but has
better performances in term of drop and output
tolerance.
A 2.85V output version is suitable for SCSI-2
active termination. Unlike PNP regulators, where
a part of the output current is wasted as quiescent
current, the LD1085 quiescent current flows into
the load, so increase efficiency. Only a 10F
minimum capacitor is need for stability.
The device is supplied in TO-220, TO-220FP,
D
2
PAK and D
2
PAK/A. On chip trimming allows the
regulator to reach a very tight output voltage
tolerance, within 1% at 25C.
LD1085
SERIES
3A LOW DROP POSITIVE VOLTAGE
REGULATOR ADJUSTABLE AND FIXED
Figure 1: Schematic Diagram
TO-220
D
2
PAK
D
2
PAK/A
TO-220FP
Rev. 14
LD1085 SERIES
2/19
Figure 2: Pin Connection (top view)
Table 1: Order Codes
(*) Available in Tape & Reel with the suffix "R" for fixed version and "-R" for adjustable version.
Table 2: Absolute Maximum Ratings
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is
not implied.
TO-220
TO-220FP
D
2
PAK (*)
D
2
PAK/A (*)
OUTPUT VOLTAGE
LD1085V15
LD1085P15
LD1085D2T15
LD1085D2M15
1.5 V
LD1085V18
LD1085P18
LD1085D2T18
LD1085D2M18
1.8 V
LD1085V25
LD1085P25
LD1085D2T25
LD1085D2M25
2.5 V
LD1085V28
LD1085P28
LD1085D2T28
LD1085D2M28
2.85 V
LD1085V33
LD1085P33
LD1085D2T33
LD1085D2M33
3.3 V
LD1085V36
LD1085P36
LD1085D2T36
LD1085D2M36
3.6 V
LD1085V50
LD1085P50
LD1085D2T50
LD1085D2M50
5.0 V
LD1085V80
LD1085P80
LD1085D2T80
LD1085D2M80
8.0 V
LD1085V90
LD1085P90
LD1085D2T90
LD1085D2M90
9.0 V
LD1085V12
LD1085P12
LD1085D2T12
LD1085D2M12
12.0 V
LD1085V
LD1085P
LD1085D2T
LD1085D2M
ADJ
Symbol
Parameter
Value
Unit
V
I
DC Input Voltage
30
V
I
O
Output Current
Internally Limited
mA
P
D
Power Dissipation
Internally Limited
mW
T
stg
Storage Temperature Range
-55 to +150
C
T
op
Operating Junction Temperature Range
-40 to +125
C
TO-220
TO-220FP
D
2
PAK
D
2
PAK/A
LD1085 SERIES
3/19
Table 3: Thermal Data
Figure 3: Application Circuits
Table 4: Electrical Characteristics Of LD1085#15 (V
I
=4.5V, C
I
= C
O
=10
F, T
A
= -40 to 125C, unless
otherwise specified.)
NOTE 1: See short-circuit current curve for available output current at fixed dropout.
Symbol
Parameter
TO-220
D
2
PAK
Unit
R
thj-case
Thermal Resistance Junction-case
3
3
C/W
R
thj-amb
Thermal Resistance Junction-ambient
50
62.5
C/W
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
O
Output Voltage
I
O
= 0 mA T
J
= 25C
1.485
1.5
1.515
V
I
O
= 0 to 5AV
I
= 3.1 to 30V (note 1)
1.47
1.5
1.53
V
V
O
Line Regulation
I
O
= 0 mA V
I
= 3.1 to 18V T
J
= 25C
0.2
4
mV
I
O
= 0 mA V
I
= 3.1 to 15V
0.4
4
mV
V
O
Load Regulation
I
O
= 0 to 3AT
J
= 25C
2
10
mV
I
O
= 0 to 3A
4
20
mV
V
d
Dropout Voltage
I
O
=3 A
1.3
1.5
V
I
q
Quiescent Current
V
I
30V
5
10
mA
I
sc
Short Circuit Current
V
I
- V
O
= 5V
3.2
4.5
A
V
I
- V
O
= 25V
0.2
0.5
A
Thermal Regulation
T
A
= 25C, 30ms pulse
0.008
0.04
%/W
SVR
Supply Voltage Rejection
f = 120 Hz, C
O
= 25
F, I
O
= 3A
V
I
= 7.5
3V
60
72
dB
eN
RMS Output Noise Voltage
(% of V
O
)
T
A
= 25C f =10Hz to 10KHz
0.003
%
S
Temperature Stability
0.5
%
S
Long Term Stability
T
A
= 125C 1000Hrs
0.5
%
R
2
V
O
= V
REF
(1 +
)
R
1
LD1085 SERIES
4/19
Table 5: Electrical Characteristics Of LD1085#18 (V
I
=4.8V, C
I
= C
O
=10
F, T
A
= -40 to 125C, unless
otherwise specified.)
NOTE 1: See short-circuit current curve for available output current at fixed dropout.
Table 6: Electrical Characteristics Of LD1085#25 (V
I
=5.5V, C
I
= C
O
=10
F, T
A
= -40 to 125C, unless
otherwise specified.)
NOTE 1: See short-circuit current curve for available output current at fixed dropout.
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
O
Output Voltage
I
O
= 0 mA T
J
= 25C
1.782
1.8
1.818
V
I
O
= 0 to 5AV
I
= 3.4 to 30V (note 1)
1.764
1.8
1.836
V
V
O
Line Regulation
I
O
= 0 mA V
I
= 3.4 to 18V T
J
= 25C
0.2
4
mV
I
O
= 0 mA V
I
= 3.4 to 15V
0.4
4
mV
V
O
Load Regulation
I
O
= 0 to 3AT
J
= 25C
2
10
mV
I
O
= 0 to 3A
4
20
mV
V
d
Dropout Voltage
I
O
=3 A
1.3
1.5
V
I
q
Quiescent Current
V
I
30V
5
10
mA
I
sc
Short Circuit Current
V
I
- V
O
= 5V
3.2
4.5
A
V
I
- V
O
= 25V
0.2
0.5
A
Thermal Regulation
T
A
= 25C, 30ms pulse
0.008
0.04
%/W
SVR
Supply Voltage Rejection
f = 120 Hz, C
O
= 25
F, I
O
= 3A
V
I
= 7.5
3V
60
72
dB
eN
RMS Output Noise Voltage
(% of V
O
)
T
A
= 25C f =10Hz to 10KHz
0.003
%
S
Temperature Stability
0.5
%
S
Long Term Stability
T
A
= 125C 1000Hrs
0.5
%
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
O
Output Voltage
I
O
= 0 mA T
J
= 25C
2.475
2.5
2.525
V
I
O
= 0 to 3AV
I
= 4.1 to 30V (note 1)
2.45
2.5
2.55
V
V
O
Line Regulation
I
O
= 0 mA V
I
= 4.1 to 18V T
J
= 25C
0.2
4
mV
I
O
= 0 mA V
I
= 4.1 to 18V
0.4
4
mV
V
O
Load Regulation
I
O
= 0 to 3AT
J
= 25C
2
10
mV
I
O
= 0 to 3A
4
20
mV
V
d
Dropout Voltage
I
O
=3 A
1.3
1.5
V
I
q
Quiescent Current
V
I
30V
5
10
mA
I
sc
Short Circuit Current
V
I
- V
O
= 5V
3.2
4.5
A
V
I
- V
O
= 25V
0.2
0.5
A
Thermal Regulation
T
A
= 25C, 30ms pulse
0.008
0.04
%/W
SVR
Supply Voltage Rejection
f = 120 Hz, C
O
= 25
F, I
O
= 3A
V
I
= 7.5
3V
60
72
dB
eN
RMS Output Noise Voltage
(% of V
O
)
T
A
= 25C f =10Hz to 10KHz
0.003
%
S
Temperature Stability
0.5
%
S
Long Term Stability
T
A
= 125C 1000Hrs
0.5
%
LD1085 SERIES
5/19
Table 7: Electrical Characteristics Of LD1085#285 (V
I
=5.85V, C
I
= C
O
=10
F, T
A
= -40 to 125C,
unless otherwise specified.)
NOTE 1: See short-circuit current curve for available output current at fixed dropout.
Table 8: Electrical Characteristics Of LD1085#33 (V
I
=6.3V, C
I
= C
O
=10
F, T
A
= -40 to 125C, unless
otherwise specified.)
NOTE 1: See short-circuit current curve for available output current at fixed dropout.
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
O
Output Voltage
I
O
= 0 mA T
J
= 25C
2.821
2.85
2.879
V
I
O
= 0 to 3AV
I
= 4.5 to 30V (note 1)
2.793
2.85
2.907
V
V
O
Line Regulation
I
O
= 0 mA V
I
= 4.5 to 18V T
J
= 25C
0.2
6
mV
I
O
= 0 mA V
I
= 4.5 to 18V
0.5
6
mV
V
O
Load Regulation
I
O
= 0 to 3AT
J
= 25C
3
15
mV
I
O
= 0 to 3A
7
20
mV
V
d
Dropout Voltage
I
O
=3 A
1.3
1.5
V
I
q
Quiescent Current
V
I
30V
5
10
mA
I
sc
Short Circuit Current
V
I
- V
O
= 5V
3.2
4.5
A
V
I
- V
O
= 25V
0.2
0.5
A
Thermal Regulation
T
A
= 25C, 30ms pulse
0.008
0.04
%/W
SVR
Supply Voltage Rejection
f = 120 Hz, C
O
= 25
F, I
O
= 3A
V
I
= 7.85
3V
60
72
dB
eN
RMS Output Noise Voltage
(% of V
O
)
T
A
= 25C f =10Hz to 10KHz
0.003
%
S
Temperature Stability
0.5
%
S
Long Term Stability
T
A
= 125C 1000Hrs
0.5
%
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
O
Output Voltage
I
O
= 0 mA T
J
= 25C
3.267
3.3
3.333
V
I
O
= 0 to 3AV
I
= 4.9 to 30V (note 1)
3.234
3.35
3.366
V
V
O
Line Regulation
I
O
= 0 mA V
I
= 4.9 to 18V T
J
= 25C
0.5
6
mV
I
O
= 0 mA V
I
= 4.9 to 18V
1
6
mV
V
O
Load Regulation
I
O
= 0 to 3AT
J
= 25C
3
15
mV
I
O
= 0 to 3A
7
20
mV
V
d
Dropout Voltage
I
O
=3 A
1.3
1.5
V
I
q
Quiescent Current
V
I
30V
5
10
mA
I
sc
Short Circuit Current
V
I
- V
O
= 5V
3.2
4.5
A
V
I
- V
O
= 25V
0.2
0.5
A
Thermal Regulation
T
A
= 25C, 30ms pulse
0.008
0.04
%/W
SVR
Supply Voltage Rejection
f = 120 Hz, C
O
= 25
F, I
O
= 5A
V
I
= 8.3
3V
60
72
dB
eN
RMS Output Noise Voltage
(% of V
O
)
T
A
= 25C f =10Hz to 10KHz
0.003
%
S
Temperature Stability
0.5
%
S
Long Term Stability
T
A
= 125C 1000Hrs
0.5
%
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