Hello,

We are planning to use ADRF6655 to down convert the received frequency 1427MHz ~ 1432MHz to 427MHz ~ 432MHz (LO -- 2GHz) but input power will be in -70dBm to -90dBm. This IC will work with this low input power.

LO frequency resolution how much it will support?

Thanks & Regards

Sushant

Hi,

This could be found on datasheet and depends on what PFD frequency you are using.

Judging by Figure 71 of the ADRF6655 datasheet, the maximum modulus value (MOD) is 2047. Table 1 says the typical PFD frequency (f

_{PFD}) is 20 MHz. So, for f_{PFD}= 20 MHz, the minimum resolution is f_{PFD}/MOD = 20 MHz / 2047 = 9.77 kHz.A typical application may use f

_{PFD}= 20 MHz and MOD = 2000; so the minimum resolution would be 10 kHz.If you use the maximum f

_{PFD}(to minimize the phase noise contribution of the N divider), then the minimum resolution becomes 40 MHz / 2000 = 20 kHz.Thanks,