SNVSAC2A March 2015 – June 2020 LM317A
PRODUCTION DATA.
Figure 20 shows a variation of the 5-V output regulator application uses the LM317A, along with an NPN transistor, to provide shutdown control. The NPN will either block or sink the current from the ADJ pin by responding to the TTL pin logic. When TTL is pulled high, the NPN is on and pulls the ADJ pin to GND, and the LM317A outputs about 1.25 V. When TTL is pulled low, the NPN is off and the regulator outputs according to the programmed adjustable voltage.
NOTE:
* Min. output ≊ 1.25 V