User's Manual

GS780MIZ Module Data Sheet
NOTES:
1. All Dimensions are in millimeters (mm).
2. For Boards using Ceramic Antenna, we recommend:
◦ Have Only Air on BOTH sides of antenna.
◦ Hang Antenna over edge of base board (best);
◦ Or, cut notch in base board under antenna area:
◦ 5mm beyond module edge on each side is good.
◦ full module width is minimum.
◦ No metal or FR4 encircling antenna area.
◦ Antenna at edge of base board, not interior of base board.
◦ Nothing conductive near antenna (e.g. battery, display, wire).
3. Module solder pads on footprint should be the same size as the pads on the module. The
three RF shield mounting holes have exposed metal. These areas must not have metal on the
customer board.
4. For best RF performance, we recommend:
◦ Using power (PWR) or GND planes from module back to power supply.
◦ Isolating PWR/GND from high frequency or high current components. For example, a
notch in GND plane to isolate from host uC.
◦ Using at least three vias when either power or GND changes layers. This applies
particularly at the module GND pins and at the VDD_RF pin.
◦ Providing a 10 uF capacitor at the VDD_RF pin and using three vias both sides of the
capacitor.
◦ Keep high speed signals away from RF areas of module.
5. For area under module, other than the antenna area, we recommend two options:
◦ No metal of any kind under module “not on any layer.”
◦ Having full GND plane under module (layer 1 or layer 2) with no “HOT” vias under
module (over 100KHz), and may route signals below GND plane. Also, no metal traces
are to be present in the circle, around shield and alignment holes. This option is best for
2-layer boards. If GND is on layer 1, use thermal relief pads for the GND pins of the
module footprint.
6. If any metal is present on layer 1, extra thick solder mask under the module is required.
7. In performing SMT or manual soldering of the module to the base board, first align the row
of pins from #11 through #20 onto the base board, then match the other two rows.
In addition to the guidelines, note the following suggestions:
1. External bypass capacitors for all module supplies should be as close as possible to the
module pins.
2. Never place the antenna very close to metallic objects.
3. External monopole antennas need a reasonable ground plane area for antenna efficiency.
4. Do not use a metallic or metalized plastic for the end product enclosure when using on-
board antenna.
5. If the module is enclosed in a plastic case, have reasonable clearance from plastic case to on-
board antenna.
GS780M-DS-00001 Page 15 Preliminary
Release 1.03 Confidential May 26, 2016