The ADF4216/ADF4217/ADF4218 is a dual frequency
synthesizer which can be used to implement local oscillators
in the up-conversion and down-conversion sections
of wireless receivers and transmitters. They can
provide the LO for both the RF and IF sections. They
consist of a low-noise digital PFD (Phase Frequency
Detector), a precision charge pump, a programmable
reference divider, programmable A and B counters and a
dual-modulus prescaler (P/P+1). The A (6-bit) and B
(11-bit) counters, in conjunction with the dual modulus
prescaler (P/P+1), implement an N divider (N= BP+A).
In addition, the 14-bit reference counter (R Counter),
allows selectable REFIN frequencies at the PFD input.
A complete PLL (Phase-Locked Loop) can be implemented
if the synthesizers are used with an external loop
filter and VCO's (Voltage Controlled Oscillators)