LD1085C
SERIES
3A LOW DROP POSITIVE VOLTAGE
REGULATOR ADJUSTABLE AND FIXED
s
s
s
s
s
s
s
s
TYPICAL DROPOUT 1.3V (AT 3A)
THREE TERMINAL ADJUSTABLE OR FIXED
OUTPUT VOLTAGE 1.5V, 1.8V, 2.5V, 2.85V,
3.3V, 3.6V, 5V, 8V, 9V, 12V.
GUARANTEED OUTPUT CURRENT UP TO
3A
OUPUT TOLERANCE
±2%
AT 25°C AND
±3%
IN FULL TEMPERATURE RANGE
INTERNAL POWER AND THERMAL LIMIT
WIDE OPERATING TEMPERATURE RANGE
-40°C TO 125°C
PACKAGE AVAILABLE : DPAK
PINOUT COMPATIBILITY WITH STANDARD
ADJUSTABLE VREG
DPAK
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 1.5V 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 10µF
minimum capacitor is need for stability.
The device is supplied in DPAK. On chip trimming
allows the regulator to reach a very tight output
voltage tolerance, within ±2% at 25°C.
SCHEMATIC DIAGRAM
July 2002
1/15
LD1085C SERIES
ABSOLUTE MAXIMUM RATINGS
Symbol
V
I
I
O
P
D
T
stg
T
op
DC Input Voltage
Output Current
Power Dissipation
Storage Temperature Range
Operating Junction Temperature Range
Parameter²
Value
30
Internally Limited
Internally Limited
-55 to +150
-40 to +125
Unit
V
mA
mW
°C
°C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is
not implied.
THERMAL DATA
Symbol
R
thj-case
R
thj-amb
Parameter
Thermal Resistance Junction-case
Thermal Resistance Junction-ambient
DPAK
3
62.5
Unit
°C/W
°C/W
APPLICATION CIRCUITS
R
2
V
O
= V
REF
(1 +
)
R
1
2/15
LD1085C SERIES
ELECTRICAL CHARACTERISTICS OF LD1085CDT15
(V
I
=4.5V, C
I
= C
O
=10µF, T
A
= -40 to 125°C,
unless otherwise specified.)
Symbol
V
O
∆V
O
∆V
O
V
d
I
q
I
sc
Parameter
Output Voltage
Line Regulation
Load Regulation
Dropout Voltage
Quiescent Current
Short Circuit Current
Termal Regulation
SVR
eN
S
S
Supply Voltage Rejection
RMS Output Noise Voltage
(% of V
O
)
Temperature Stability
Long Term Stability
I
O
= 0 mA
I
O
= 0 mA
I
O
= 0 mA
I
O
= 0 to 3A
I
O
=3 A
V
I
≤
30V
V
I
- V
O
= 5V
V
I
- V
O
= 25V
T
A
= 25°C, 30ms pulse
f = 120 Hz, C
O
= 25
µF,
I
O
= 3A
V
I
= 7.5
±
3V
T
A
= 25°C
f =10Hz to 10KHz
60
3.2
0.2
Test Conditions
T
J
= 25°C
V
I
= 3.1 to 18V
V
I
= 3.1 to 15V
T
J
= 25°C
I
O
= 0 to 3A V
I
= 3.1 to 30V (note 1)
Min.
1.47
1.455
Typ.
1.5
1.5
0.2
0.4
2
4
1.3
5
4.5
0.5
0.003
75
0.003
0.5
0.5
0.015
Max.
1.53
1.545
4
4
10
20
1.5
10
Unit
V
V
mV
mV
mV
V
V
mA
A
A
%/W
dB
%
%
%
I
O
= 0 to 3A T
J
= 25°C
T
A
= 125°C
1000Hrs
NOTE 1: See short-circuit current curve for available output current at fixed dropout.
ELECTRICAL CHARACTERISTICS OF LD1085CDT18
(V
I
=4.8V, C
I
= C
O
=10µF, T
A
= -40 to 125°C,
unless otherwise specified.)
Symbol
V
O
∆V
O
∆V
O
V
d
I
q
I
sc
Parameter
Output Voltage
Line Regulation
Load Regulation
Dropout Voltage
Quiescent Current
Short Circuit Current
Termal Regulation
SVR
eN
S
S
Supply Voltage Rejection
RMS Output Noise Voltage
(% of V
O
)
Temperature Stability
Long Term Stability
I
O
= 0 mA
I
O
= 0 mA
I
O
= 0 mA
I
O
= 0 to 3A
I
O
=3 A
V
I
≤
30V
V
I
- V
O
= 5V
V
I
- V
O
= 25V
T
A
= 25°C, 30ms pulse
f = 120 Hz, C
O
= 25
µF,
I
O
= 3A
V
I
= 7.5
±
3V
T
A
= 25°C
f =10Hz to 10KHz
60
3.2
0.2
Test Conditions
T
J
= 25°C
V
I
= 3.4 to 18V
V
I
= 3.4 to 15V
T
J
= 25°C
I
O
= 0 to 3A V
I
= 3.4 to 30V (note 1)
Min.
1.764
1.746
Typ.
1.8
1.8
0.2
0.4
2
4
1.3
5
4.5
0.5
0.003
75
0.003
0.5
0.5
0.015
Max.
1.836
1.854
4
4
10
20
1.5
10
Unit
V
V
mV
mV
mV
V
V
mA
A
A
%/W
dB
%
%
%
I
O
= 0 to 3A T
J
= 25°C
T
A
= 125°C
1000Hrs
NOTE 1: See short-circuit current curve for available output current at fixed dropout.
4/15
LD1085C SERIES
ELECTRICAL CHARACTERISTICS OF LD1085CDT25
(V
I
=5.5V, C
I
= C
O
=10µF, T
A
= -40 to 125°C,
unless otherwise specified.)
Symbol
V
O
∆V
O
∆V
O
V
d
I
q
I
sc
Parameter
Output Voltage
Line Regulation
Load Regulation
Dropout Voltage
Quiescent Current
Short Circuit Current
Termal Regulation
SVR
eN
S
S
Supply Voltage Rejection
RMS Output Noise Voltage
(% of V
O
)
Temperature Stability
Long Term Stability
I
O
= 0 mA
I
O
= 0 mA
I
O
= 0 mA
I
O
= 0 to 3A
I
O
=3 A
V
I
≤
30V
V
I
- V
O
= 5V
V
I
- V
O
= 25V
T
A
= 25°C, 30ms pulse
f = 120 Hz, C
O
= 25
µF,
I
O
= 3A
V
I
= 7.5
±
3V
T
A
= 25°C
f =10Hz to 10KHz
60
3.2
0.2
Test Conditions
T
J
= 25°C
V
I
= 4.1 to 18V
V
I
= 4.1 to 18V
T
J
= 25°C
I
O
= 0 to 3A V
I
= 4.1 to 30V (note 1)
Min.
2.45
2.425
Typ.
2.5
2.5
0.2
0.4
2
4
1.3
5
4.5
0.5
0.008
72
0.003
0.5
0.5
0.04
Max.
2.55
2.575
5
5
10
20
1.5
10
Unit
V
V
mV
mV
mV
V
V
mA
A
A
%/W
dB
%
%
%
I
O
= 0 to 3A T
J
= 25°C
T
A
= 125°C
1000Hrs
NOTE 1: See short-circuit current curve for available output current at fixed dropout.
ELECTRICAL CHARACTERISTICS OF LD1085CDT285
(V
I
=5.85V, C
I
= C
O
=10µF, T
A
= -40 to 125°C,
unless otherwise specified.)
Symbol
V
O
∆V
O
∆V
O
V
d
I
q
I
sc
Parameter
Output Voltage
Line Regulation
Load Regulation
Dropout Voltage
Quiescent Current
Short Circuit Current
Termal Regulation
SVR
eN
S
S
Supply Voltage Rejection
RMS Output Noise Voltage
(% of V
O
)
Temperature Stability
Long Term Stability
I
O
= 0 mA
I
O
= 0 mA
I
O
= 0 mA
I
O
= 0 to 3A
I
O
=3 A
V
I
≤
30V
V
I
- V
O
= 5V
V
I
- V
O
= 25V
T
A
= 25°C, 30ms pulse
f = 120 Hz, C
O
= 25
µF,
I
O
= 3A
V
I
= 7.85
±
3V
T
A
= 25°C
f =10Hz to 10KHz
60
3.2
0.2
Test Conditions
T
J
= 25°C
V
I
= 4.5 to 18V
V
I
= 4.5 to 18V
T
J
= 25°C
I
O
= 0 to 3A V
I
= 4.5 to 30V (note 1)
Min.
2.793
2.765
Typ.
2.85
2.85
0.2
0.5
3
7
1.3
5
4.5
0.5
0.008
72
0.003
0.5
0.5
0.04
Max.
2.907
2.935
6
6
15
20
1.5
10
Unit
V
V
mV
mV
mV
V
V
mA
A
A
%/W
dB
%
%
%
I
O
= 0 to 3A T
J
= 25°C
T
A
= 125°C
1000Hrs
NOTE 1: See short-circuit current curve for available output current at fixed dropout.
5/15
京公网安备 11010802033920号
EEWORLD
