The ADF4371 allows implementation of fractional-N or Integer N phase-locked loop (PLL) frequency synthesizers when used with an external loop filter and an external reference frequency. The wideband microwave voltage controlled oscillator (VCO) design allows frequencies from 62.5 MHz to 32 GHz to be generated.
The ADF4371 has an integrated VCO with a fundamental output frequency ranging from 4000 MHz to 8000 MHz. In addition, the VCO frequency is connected to divide by 1, 2, 4, 8, 16, 32, or 64 circuits that allows the user to generate radio frequency (RF) output frequencies as low as 62.5 MHz at RF8x. A frequency multiplier at RF16x generates from 8 GHz to 16 GHz. A frequency quadrupler generates frequencies from 16 GHz to 32 GHz at RF32x. RFAUX8x duplicates the frequency range of RF8x or permits direct access to the VCO output. To suppress the unwanted products of frequency multiplication, a harmonic filter exists between the multipliers and the output stages of RF16x and RF32x.
Control of all on-chip registers is through a 3-wire interface. The ADF4371 operates with analog and digital power supplies ranging from 3.15 V to 3.45 V, and 5 V for the VCO power supply. The ADF4371 also contains hardware and software power-down modes.
