LM1085
3A Low Dropout Positive Regulators
General Description
The LM1085 is a series of low dropout positive voltage regulators
with a maximum dropout of 1.5V at 3A of load current. It has the
same pin-out as National Semiconductor’s industry standard LM317.
The LM1085 is available in an adjustable version, which can set the
output voltage with only two external resistors. It is also
available in three fixed voltages: 3.3V, 5.0V and 12.0V. The fixed
versions integrate the adjust resistors.
The LM1085 circuit includes a zener trimmed bandgap reference,
current limiting and thermal shutdown.
The LM1085 series is available in TO-220 and TO-263 packages. Refer
to the LM1084 for the 5A version, and the LM1086 for the 1.5A
version.
Features
- Available in 3.3V, 5.0V, 12V and Adjustable Versions
- Current Limiting and Thermal Protection
- Output Current 3A
- Line Regulation 0.015% (typical)
- Load Regulation 0.1% (typical)
Applications
- High Efficiency Linear Regulators
- Battery Charger
- Post Regulation for Switching Supplies
- Constant Current Regulator
- Microprocessor Supply
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required, please
contact the National Semiconductor Sales Office/ Distributors for
availability and specifications.
Maximum Input to Output Voltage Differential
LM1085-ADJ 29V
LM1085-12 18V
LM1085-3.3 27V
LM1085-5.0 25V
Power Dissipation (Note 2) Internally Limited
Junction Temperature (TJ)(Note 3) 150˚C
Storage Temperature Range -65˚C to 150˚C
Lead Temperature 260˚C, to 10 sec
ESD Tolerance (Note 4) 2000V
Operating Ratings (Note 1)
Junction Temperature Range (TJ) (Note 3)
Control Section −40˚C to 125˚C
Output Section −40˚C to 150˚C
Connection Diagrams
Basic Functional Diagram, Adjustable Version
Simplified Schematic
