Other Parts Discussed in Thread: CC2541
Hi,
customer has an certification issue, there is spur at 64MHz (about -4xdbm).
Looks it is known issue. There is a note in datasheet as below, we tried the resonator circuit, adding the components on the strip line to GND, between reference design part and antenna matching circuit, the spur is gone (blew -65dBm)
we have two questions:
1. the TX power is decreased about 2~3dB, do you see the same? or we need to fine tune the circuit or optimize the soldering.
2. we found CC2541 has better spur on 64MHz, without the resonator, it can meet the spec, (about -60dBm). do you see me same?
3. Unfortunitely, at this stage, customer is hard to switch it to CC2541 (extra money to test lab and they need 4dBm tx power), and have to re-spin the PCB board. so they are wondering, if there is other solution to pass the spur. it is better by a patch, or just tune the RF front end component value, not topology.
BR. Albin
"(1) Designs with antenna connectors that require conducted ETSI compliance at 64 MHz should insert an LC resonator in front of the
antenna connector. Use a 1.6-nH inductor in parallel with a 1.8-pF capacitor. Connect both from the signal trace to a good RF ground."
