LM7002M data sheet vs schematic

System Development
1

These pins are grounded in LimeSDR-USB schematic , however, these pins are not listed in the data sheet. Please advise and thanks in advance.
PSUB_TPAD_TRF
GND_TPAD_TRF

2

After looking at the schematic for the LimeNET-Micro (Which looks to be using a newer LimeMicro Altium Library Part in the Schematic), it also has non standard pin with a “Pin ID” of GND, a “Pin Name” of “EP” and is listed in a section called “Thermal pad”.

This would make me believe that one might be a designation for the Thermal ground PAD (TPAD), which does not have a “pin number” (The large 6.989 mm x 6.989 mm centre pad in the middle of the 261L aQFN).
The thermal pad that is used for both a low inductance electrical path to the RF ground plane and also provides a low thermal resistance to the ground plane of the PCB for heat dissipation.

Pin No    Pin ID  Pin Name        Type     Description  Notes
unlisted  GND     PSUB_TPAD_TRF   missing  missing      missing
unlisted  GND     GND_TPAD_TRF    missing  missing      missing

Another possibly is that it was a copy and paste accident when the LimeMicro Altium Library Part was created.

Maybe the Altium Library Schematic Part needs to be updated with additional information, at least for the LimeSDR-USB and LimeSDR-Mini. And the datasheet should have a line added for the thermal pad with a pin number allocated. Maybe 0 or 262, I don’t know maybe using zero might be easier.

3

@Zack could you clarify, please.

4

Hi @nashimazrim, @mzs,

LMS7002M Altium symbol was updated at some point. In the older version there were two pins named PSUB_TPAD_TRF, GND_TPAD_TRF and both were actually the same, while connected to Exposed Pad (EP). In the latest version these two were joined to one and named as EP (GND).

The best idea is to use the latest symbol from LimeNet-Micro project (https://github.com/myriadrf/LimeNET-Micro).

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