Locosys MC-1612 Hardware Design Manual page 8

3 Layout Guideline
3.1 Layout underneath the GPS module
GPS signal is very weak signal level around -160dBm~130dBm. Any noise or harmonic will
decrease the quality of GPS. In modern GPS product, it almost includes LCD, MCU, High Speed
digital and RF system (BT, Wi-Fi, DVB-T...). In order to minimize the influence of mentioned noise
to GPS module, please customer don't place any trace underneath the GPS module. In other word,
give GPS module a clean GND plane is very important.
GPS on a clean GND plane
3.2 Module Placement
Place the decoupling capacitors close to GPS module
Place the damping resistors close to GPS module
Do not place:
GPS module close to high-speed digital processing circuitry
GPS module close to high-current switching power circuitry
GPS module close to clock sources circuitry
3.3 Trace
(1). The USB differential signals should be trace close and equal-length for minimum radiation and
noise immunity.
(2). Please have the RF traces had the character impendence of 50 ohm for good impedance
matching.
(3). Any right angle turn in trace routing should be accomplished with two 135 degree turn or an arc
turn
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LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi Dist., New Taipei City 221, Taiwan
886-2-8698-3698
886-2-8698-3699
www.locosystech.com