LM317 short circuit protection

Seth,

Are you asking if LM317 can be a voltage regulator and a current limiter (other than internal current limit) at the same time? No it can not.
There are way to implement this in some cases.

If this is a fixed voltage output regulation circuit.
What is min, max input voltage?
What is min max load current?
What is output voltage?

Hi Ron,

I will only use it as a current limiter.
A 24V supply will power a sensor, 4mA min and 20mA max current loop. I need to insert a circuit in between to protect the rest of the circuit in the event of a short circuit on the sensor. Rather than breaking the circuit via fuse, I would like to maintain a current of 30mA max for monitoring purposes. There is an IC from competitor to do this but the thermal spec is a concern.
Please advice if there is a TI component to do such function.

Seth,

LM317 can do that with one resistor added. 1.25V/30mA = 42 ohms.
At maximum normal 20mA there will be a 0.84V drop across resistor and about 1.5V across LM317 for a total near 2.34V.
Round that up to 3V to cover temperature and 21V is left for sensor and receiver.

If the sensor shorts then LM317 will drop as much of the 24V as needed to limit loop current to 30mA.

Ron,

What would be the theoretical temeperature of the device when this occurs (24V across LM317)? I dont see a heat sink specs or requirement on the data sheet.

Seth,

For 24V across LM317, Pd = 30mA * 24V = 720mW.
Tj-Ta = Pd * Tja
Three packages with Tja at [53, 19, 25]C/W
Temperature rise (Tj-Ta) = [38, 14, 18]C