TMP275 Layout Guidelines

Hi Jackie,

We do not have any stand-alone documentation regarding layout for the TMP275.  However, the datasheet provides a brief section on placing the TMP275 on page 5. 

Basically IC/die itself is the temperature sensor and both the package and the metal leads provide thermal paths from the outside world to the sensor inside the package.  Since the thermal resistance of the metal leads on the package is lower than that of the packaging material, the leads provide the primary thermal path to the sensor.

Therefore try to place the GND pin of the device, which is connected directly to the substrate of the die, as close to the object/plane that is being measured. 

If there are air-drafts/air-currents in the application, the package and leads should be isolated from these air drafts and to avoid temperature measurement errors due to the difference between the air-draft temperature and the desired temperature being measured.  A way to isolate the leads and package from these air drafts is to use a thermally conductive adhesive. 

Other layout suggestions are to ensure close proximity of the external decoupling capacitor to the V+ pin, and to route the SCL/SDA lines with a GND signal between them to avoid heavy capacitive coupling between the I2C signals.

Let me know if the customer is looking for something different that the information provided above.

Best Regards,
Collin Wells
Precision Analog
Linear Applications