TMP451-Q1: How should I understand the meaning of remote and local temperature

Hello，

TMP451 means that the IC itself will monitor the temperature of the "local" position (i.e. where the device is placed) with a built-in local temperature sensor， but it also has capability to measure the temperature of alternate locations on a PCB via external transistors (or thermal diode). These external transistors are typically low-cost discrete NPN or PNP transistors, or substrate thermal transistors or diodes that are integral parts of microprocessors, microcontrollers, or FPGAs.

About “how far can my remote be from the remote temperature sensor,”  please refer to the FAQ:

https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/892904/faq-remote-temperature-sensors-how-far-can-my-remote-be-from-the-remote-temperature-sensor