UM-B-074
DA1468x Range Extender Daughterboard
User Manual
Revision 1.1
17-Apr-2018
CFR0012
23 of 60
© 2018 Dialog Semiconductor
At the ANT1 port a printed Inverted-F Antenna (IFA) with 0 dBi gain is used. At the ANT2 port a uFL
connector (J5) is used for connecting external antennas. Pi-networks Z4, Z5, Z6 and Z9, Z10, Z11
can be used for matching purposes on both antenna ports.
For the ANT1 port a series capacitor of Z4 = 1.8 pF is used for optimum power transfer.
Figure 15: ANT1, Printed IFA Antenna and Matching Network (Z4 = 1.8 pF)
The reference design provides an SMD RF switch (J3) in series to the printed IFA antenna. The SMD
RF switch is used for conducted RF evaluation/testing. The RF switch type is MM8130-2600 supplied
by Murata. Verification of the circuit performance is accomplished by inserting an external plug in the
board mounted receptacle. This action re-directs the circuit from normal condition to the plug side.
Removing the plug restores circuit back to its normal condition.
7.1.8
Resistive Attenuator (Optional)
Between DA14680/681 and SKY66112-11 a resistive attenuator circuit can be added if needed.
Capacitors Z1, Z2 and Z8 must then be replaced by suitable resistors to achieve the desired
attenuation, while matching the 50
impedance.
Figure 16: Resistive Attenuator Between DA14681 and SKY66112-11
