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[FAQ] TMP61: Can I use a TMP61 DYA package on an 0805 foot print

Part Number: TMP61
Other Parts Discussed in Thread: TMP63, TMP64

When upgrading existing NTC applications to leverage TMP6 technology benefits; for the TMP61, TMP63 or TMP64 Positive Temperature Coefficient (PTC) Thermistors, what are all the standard component footprints that the DYA package variant supports? 

  • The TMP6 parts are currently available in a X1SON (DEC), SOT-5X3 (DYA) and TO-92S (LPG) packages. Here the question is about the DYA package variant. While the datasheet highlights the SOT-5X3/DYA package being 0603/1608 footprint compatible, it is also in fact compatible with the 0805/2012 footprint, due to its unique lead frame dimensions.

    When the DYA, IPC 0603 and IPC 0805 PCB footprints are overlaid, as shown in image below, it can be seen that the recommended PCB foot print for the DYA has a slightly larger space recommendation than the 0603/1608 or the 0805/2012. The important part to observe in this comparison is to ensure the heel of the TMP6 pins, as landed on the 0805/2012 pads will allow for the required heel fillet according to the IPC-A-610G standards (for solder quality). The toe and side fillets will easily meet the same IPC-A-610G requirements with the larger pad size that the 0805/2012 footprint presents as compared to either the 0603/1608 or the DYA footprint.

    As seen below in the top down drawing the device has plenty of room for the toe and side to be placed on the PCB pads. The top down images are confirmation of a reasonable fit on 0805/2012 pads.

    The side drawing view (below) shows that the heel fully sits on the 0805 pad. The side image also confirms the ability to place the DYA package on 0805/2012 PCB pads.

    The arrows point out that the inside dimension of the DYA do comply with the IPC-A-610G standards.

    Other angle images

    Note: There will be an excess amount of solder paste that will be applied to the pads when using the TMP6 DYA package on an 0805 pad. The extra solder paste can cause floating that will allow the part to move around during reflow. Some solder balling may also occur. To solve these issues, reduce the aperture size of the solder paste for these pads.


    Gordon Varney

    Sr. Applications / Systems Engineer

    MGTS (Member Group Technical Staff)

     Easy and accurate temperature monitoring and protection