Sometimes a customer tells us that they’ve received a Texas Instruments part, but the logo on it is an ‘NS’. Is the part invalid?
Many TI devices such as LM78L05AIMX that are originally released by a different company company before it was acquired by Texas Instruments retain the topside marking of the original company. LM78L was originally released by National Semiconductor before Texas Instruments acquired National Semiconductor. As such LM78L still has the National Semiconductor logo on its topside marking.
Another way to look at it, is that when a company buys another one, TI doesn’t change the part numbers but keep them the same, as customers in the market have ordered it under the OPN they are used to. Texas Instruments also keeps the same logo, to help keep the part the same for old and new customers.