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MT3329 GPS External Antenna Connection

https://drive.google.com/uc?id=0B_FuMGaqECLuWU41dTJYT2FyZjg&export=view
MediaTek MT3329 GPS Receiver from rhydoLabz


The MT3329 SoC from MediaTek is a low power- high gain GPS receiver. I bought one of this from RhydoLabz (Part number : GPS-2261, 5V TTL Serial). It has a patch antenna on top. I used the GPS for my VANET project. The GPS and other accompanying modules are installed into a small remote controlled rover which has a full metal housing. So the metallic enclosure of the rover prevents the GPS from receiving signals from satellites. Therefore I have to open the cover each time for the GPS to receive any signal. To solve this I decided to add an external antenna to the GPS. But when I checked the datasheet of the MT3329, it had no external antenna pin, but the MediaTek website was showing that the chip could be connected to an external antenna. Then I checked another datasheet of the same chip, and that one said an external antenna could be connected and showed the pin details. This lead me to total confusion. 


https://drive.google.com/uc?id=0B_FuMGaqECLubW5iUENIeW9qZTQ&export=view

Conflict between two block diagrams


May be there are multiple functions for those pins. Whatever, after some close inspection of the module I bought, I found that it had a footprint for an SMA connector which had not used by the manufacturers. One of the datasheet I checked shows D+ on pin 6 and D- on the pin 7 which are the USB pins for direct USB connection. The other datasheet shows pin 6 as GND and pin 7 as EXANT. The module I bought had the SMA footprint connected to the pin 7 of the chip and the pin 6 was connected to the GND. Having found out the functions of the pins, I connected an external antenna to pin 7 of the MT3329 and it worked great !


https://drive.google.com/uc?id=0B_FuMGaqECLuZER1SDh5bjVuWkU&export=view
MT3329 GPS External antenna connection



Time-stamp

Date published : 8:39 PM 21-04-2015, Tuesday
Last updated : 11:44 AM 01-04-2016, Friday

Downloads

Following are some PDF files related to the MT3329 including the conflicting product datasheets (the first two). I couldn't find any official datasheet from MediaTek. RhydoLabz didn't provide one either.

  1. https://drive.google.com/open?id=0B_FuMGaqECLudDhKeWt3cHgwYjQ&authuser=0
  2. https://drive.google.com/open?id=0B_FuMGaqECLuZ0p3cDF2aC0wNlk&authuser=0
  3. https://drive.google.com/open?id=0B_FuMGaqECLucVpwTDk3ZVEwWFk&authuser=0
  4. https://drive.google.com/open?id=0B_FuMGaqECLucmlkRzdNbHNhaDQ&authuser=0
  5. https://drive.google.com/open?id=0B_FuMGaqECLuT0kyaE5YV3Q2UFk&authuser=0
  6. https://drive.google.com/open?id=0B_FuMGaqECLuVjB2N2ZsWnRwOTQ&authuser=0
  7. https://drive.google.com/open?id=0B_FuMGaqECLuVjB2N2ZsWnRwOTQ&authuser=0
  8. https://drive.google.com/open?id=0B_FuMGaqECLua3p3OW1HeGxlZWs&authuser=0
  9. https://drive.google.com/open?id=0B_FuMGaqECLuaUlwd3NCRUYzdFU&authuser=0
  10. https://drive.google.com/open?id=0B_FuMGaqECLub0xmTWZ6Y3hIREk&authuser=0
  11. https://drive.google.com/open?id=0B_FuMGaqECLua1RCUEcwUkVWSDg&authuser=0

Links

  1. RhydoLabz - Where I bought the module from
  2. MediaTek - Manufacturer website with no relevant documents
  3. Four Wheel Ground Rover - Where I used the GPS module