Explore LM317 pins, signal names, electrical functions and connection guidance for each package.
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The control loop holds approximately 1.25 V between OUTPUT and ADJUST.
Connect R1 from OUTPUT to ADJUST and R2 from ADJUST to the load return.
Adjustment current flows out of this pin; include IADJ × R2 when estimating output voltage. This is not a ground pin.
Supplies the load and the external feedback divider. The metal tab is also OUTPUT.
Connect the load and the top of R1 here. Keep the R1 connection close to the output lead.
The exposed TO-220 tab and D²PAK thermal pad are electrically live at output voltage; isolate a grounded heatsink where needed.
Feeds the pass stage from a DC voltage sufficiently above the requested output.
Place a 0.1 µF input bypass close to the device when required by the supply wiring.
The 40 V absolute limit is input-to-output differential, not a recommended operating input or an unconditional output range.
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