User's Manual

UMTS/HSPA Module Series
UC20 User Manual
UC20_Hardware_Design Confidential / Released 60 / 84
5.2.2. Reference Design for Active Antenna
Active
antenna
VDD
Module
ANT_GNSS
47nH
10R
0.1uF
100pF
NMNM
Figure 35: Reference Circuit of GNSS Active Antenna
1. You can choose the corresponding reference circuit above according to your demands on antenna
circuit design.
2. MAX2659 is the recommended LNA chip. You can disable LNA to save power with one GPIO
shown in above figure. Pay attention to this pin’s voltage level.
3. VDD supplies power for active antenna. You can choose the right VDD according to the requirements
for active antenna. This power circuit is not needed if passive antenna is applied here.
4. All NM capacitors are reserved for adjusting RF performance.
5. The capacitance of ESD component D1 should be less than 1pF.
5.3. Antenna Installation
5.3.1. Antenna Requirement
The following table shows the requirement on GSM/UMTS antenna and GNSS antenna.
NOTES