Vague Mouser datasheet - LM317 max amp

OBW0549

Joined Mar 2, 2015
3,566
Nothing vague about it; under Maximum Ratings it says the maximum output current is internally limited. That means that the LM317's internal circuitry will limit the current (i.e., by reducing the output voltage) to a safe value. The maximum power dissipation of the chip is also internally limited to a safe value (presumably by monitoring the die temperature).

Under Electrical Characteristics, the Maximum Load Current is listed as 1.5 amps minimum, 2.2 amps typical. That says the internal current limiting will allow you to draw at least 1.5 amps, and in most cases 2.2 amps.

The safe thing to do (to avoid bitter disappointment) is to not count on getting any more than 1.5 amps from the device.
 

bertus

Joined Apr 5, 2008
22,303
Hello,

In the electrical data there is clearly given the typical output current for two cases:

LM317_max_current.png

There is even a graph that shows the max output current for the different dropout voltages:

LM317_max_current_versus_dropout_voltage.png

Bertus
 

dl324

Joined Mar 30, 2015
17,106
So the mouser datasheet I'm looking at is being kind of vague on what's the max amps I pull from the LM317. Any ideas?
Conservative designers always use the worst case value specified by the manufacturer. Using anything else requires incoming testing to test for the desired characteristic(s).
 
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