LT1085GMD
LT1085IGDII
LT1085SMD
3 AMP POSITIVE
VOLTAGE REGULATOR
INPUT
SAFE AREA
PROTECT ION
CU RR EN T
LIMITING
AMPLIFIER
L IM I T
OU TPUT
SEN SE
T H E R M AL
O V ER L O AD
FEATURES
• Low Dropout Performance
• Fixed or Adjustable Voltages
• Fixed Output Voltages of 3.3V, 5V & 12V
• Adjustable Output Voltage Range From 1.2V
• Line Regulation 0.015% / V Typical.
• Load Regulation 0.01% Typical.
• Available in Hermetically Sealed TO–3, SMD1 and
TO–257 (isolated & non-isolated) Packages.
• Military Temperature Range (–55 to +150°C)
DEVICE
(1)
LT1085K–XX
LT1085G–XX
LT1085IG–XX
LT1085SMD–XX
PACKAGE
TO–3
TO–257
Isolated TO–257
SMD1
VOL T AGE
REGUL ATION
AMPLIFIER
V
R E F
ADJUST
DESCRIPTION
The LT1085 voltage regulators are monolithic inte-
grated circuits designed for use in applications
requiring a well regulated positive output voltage
with low input-output differential voltage.
Note
1) –XX = Voltage Option: 3.3, 5 or 12
–XX = Left blank for Adjustable Option.
Features include full power usage of up to 3A load current, internal current limiting and thermal shutdown. Safe area
protection on the die is also included, providing protection of the series pass Darlington transistor under most conditions.
The hermetically sealed TO–3 packages are utilised for high reliablitiy and low thermal resistance, whilst the SMD1
package is designed for surface mount applications.
ABSOLUTE MAXIMUM RATINGS
(T
case
= 25°C unless otherwise stated)
V
IN
P
D
R
q
JC
R
q
JC
R
q
JC
T
J
T
STG
T
LEAD
Input – Output Voltage Differential
Power Dissipation
Thermal Resistance Junction To Case
Thermal Resistance Junction To Case
Thermal Resistance Junction To Case
Operating Junction Temperature Range
Storage Temperature Range
Lead Temperature (for 10 sec.)
Telephone +44(0)1455 556565. Fax +44(0)1455 552612.
E-mail:
sales@semelab.co.uk
Website:
http://www.semelab.co.uk
35V
Internally limited *
TO–3
TO–3
SMD1
SMD1
TO–257
TO–257
Control
Power
Control
Power
Control
Power
Control
Power
0.93°C / W
3.0°C / W
0.79°C / W
4.0°C / W
0.79°C / W
4.0°C / W
–55 to 150°C
–55 to 200°C
–65 to 150°C
300°C
Prelim. 7/00
* These ratings are only applicable for power dissipations of 30 Watts over a limited range of V
IN
– V
OUT
.
Semelab plc.
LT1085GMD
LT1085IGDII
LT1085SMD
ELECTRICAL CHARACTERISTICS
Parameter
(T
J
= 25°C Unless otherwise stated)
1,2
Output
Voltage Test Conditions
3.3
V
IN
– V
OUT
= 6.3V
I
O
= 10mA to 3A
V
IN
– V
OUT
= 8V
I
O
= 10mA to 3A
V
IN
– V
OUT
= 15V
I
O
= 10mA to 3A
Min.
I
O
= 10mA
T
J
= Over Temp
I
O
= 10mA
T
J
= Over Temp
I
O
= 10mA
T
J
= Over Temp
I
O
= 10mA
T
J
= Over Temp
T
J
= 25°C
T
J
= Over Temp
I
O
= 10mA
T
J
= 25°C
T
J
= Over Temp
T
J
= Over Temp
T
J
= Over Temp
T
J
= Over Temp
T
J
= Over Temp
T
J
= 25°C
3
3
3
3
3
3
3
3
3
3
Typ.
3.3
3.3
5
5
12
12
1.25
1.25
0.015
0.035
0.05
0.1
0.2
1.3
Max.
3.333
3.366
5.05
5.10
12.12
12.24
1.262
1.270
0.2
Unit
3.267
3.234
4.95
4.90
11.88
11.76
1.238
1.225
V
O
4
Output Voltage
5
V
12
V
REF
4
Reference Voltage
ADJ.
V
IN
– V
OUT
= V
O
+ 3V
I
O
= 10mA to 3A
V
IN
– V
OUT
= 1.5 to 15V
I
O
= 10mA
V
IN
– V
OUT
= 1.5 to 35V
T
J
= Over Temp
3
V
%
REG
(LINE)
4
Line Regulation
0.6
0.3
0.4
1.5
%
REG
(LOAD)
V
D
I
CL
I
Q
4
Load Regulation
Dropout Voltage
Current Limit
Quiescent Current
V
IN
– V
OUT
= 3V
V
IN
– V
OUT
= 3V
%
V
A
mA
%/W
D
V
OUT
,
D
V
REF
= 1%
V
IN
– V
OUT
= 5V
V
IN
– V
OUT
= 25V
V
IN
– V
OUT
= 35V
t
p
= 30ms
T
J
= 25°C
T
J
= Over Temp
T
J
= Over Temp
V
IN
– V
OUT
= 5V
T
J
= Over Temp
T
J
= Over Temp
T
J
= 25°C
6
3
3
3
3.2
0.2
4.0
0.5
10
0.002
55
120
0.2
5
0.01
REG
(THERM)
Thermal Regulation
I
PIN
Adjust Pin Current
Adjust Pin Current Change
Temperature Stability
m
A
m
A
%
D
I
PIN
T
S
I
O
V
N
R
A
I
O
= 0.5A
I
O
= 0.5A
0.5
Minimum Load Current
RMS Output Noise
5
V
IN
– V
OUT
= 25V
3
5
0.003
10
mA
%V
O
dB
Ripple Rejection Ratio
V
IN
– V
OUT
= 3V
T
J
= Over Temp
3
I
O
= 3A
60
75
Notes
1. Test Conditions unless otherwise stated:
V
IN
= 1.5 to 35V, or Maximum Input, whichever is less.
I
O
= 10mA to 3A.
2. These specifications are only applicable for power dissipations of 30 Watts over a limited range of V
IN
– V
OUT
.
3. Over Temp. = Over specified Junction Temperature Range (See Absolute Maximum Ratings).
4. Low duty cycle pulse test with Kelvin connections required. Changes in output voltage are covered under the specification
for thermal regulation.
5. Bandwidth of 10Hz to 10kHz.
6. 120Hz input ripple, 15V = 64dB min. C
OUT
(C
ADJ
) = 25
m
F.
Semelab plc.
Telephone +44(0)1455 556565. Fax +44(0)1455 552612.
E-mail:
sales@semelab.co.uk
Website:
http://www.semelab.co.uk
Prelim. 7/00
LT1085GMD
LT1085IGDII
LT1085SMD
K Package (TO–3)
40.01 (1.575)
Max.
G & IG Packages (TO–257)
10.41 (0.410)
10.67 (0.420)
4.83 (0.190)
5.08 (0.200)
0.89 (0.035)
1.14 (0.045)
16.38 (0.645)
16.89 (0.665)
13.38 (0.527)
13.64 (0.537)
4.47 (0.176)
Rad.
2 Pls.
10.41 (0.410)
10.92 (0.430)
26.67
(1.050)
Max.
3.56 (0.140)
Dia.
3.81 (0.150)
1 2 3
12.07 (0.500)
19.05 (0.750)
22.23 (0.875)
Max.
11.43 (0.450)
6.35 (0.250)
1.09 (0.043)
0.97 (0.038)
Dia.
30.40 (1.197)
29.90 (1.177)
12.19 (0.48)
11.18 (0.44)
0.64 (0.025)
Dia.
0.89 (0.035)
2.54 (0.100)
BSC
3.05 (0.120)
BSC
1.63 (0.064)
1.52 (0.060)
SMD1 PACKAGE
2
11.18 (0.440)
10.67 (0.420)
4.09 (0.161)
3.84 (0.151)
2 Pls
4 .1 4 (0 .1 6 3 )
3 .8 4 (0 .1 5 1 )
0 .8 9
(0 .0 3 5 )
m in .
3 .7 0 (0 .1 4 6 )
3 .7 0 (0 .1 4 6 )
3 .4 1 (0 .1 3 4 )
3 .4 1 (0 .1 3 4 )
3 .6 0 (0 .1 4 2 )
M a x .
1
3
0 .7 6
(0 .0 3 0 )
m in .
1
1 0 .6 9 (0 .4 2 1 )
1 0 .3 9 (0 .4 0 9 )
2
16.97 (0.668)
16.87 (0.664)
9 .6
9 .3
1 1 .5
1 1 .2
7 (0
8 (0
8 (0
8 (0
.3 8
.3 6
.4 5
.4 4
1 )
9 )
6 )
4 )
1 6 .0 2 (0 .6 3 1 )
1 5 .7 3 (0 .6 1 9 )
0 .5 0 (0 .0 2 0 )
0 .2 6 (0 .0 1 0 )
LT1085
Pin
1
2
Fixed
Adjustable
COMMON
ADJUST
INPUT
INPUT
Case is OUTPUT
Pin
1
2
3
LT1085SMD
Fixed
COMMON
OUTPUT
INPUT
Adjustable
ADJUST
OUTPUT
INPUT
LT1085G
Pin
1
2
3
Fixed
Adjustable
COMMON
ADJUST
OUTPUT
OUTPUT
INPUT
INPUT
Case is OUTPUT
Pin
1
2
3
LT1085IG
Fixed
Adjustable
COMMON
ADJUST
OUTPUT
OUTPUT
INPUT
INPUT
Case is ISOLATED
Prelim. 7/00
Semelab plc.
Telephone +44(0)1455 556565. Fax +44(0)1455 552612.
E-mail:
sales@semelab.co.uk
Website:
http://www.semelab.co.uk
