The ADF5611 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 source. The wideband
microwave voltage controlled oscillator (VCO) design permits
frequency operation from 7300MHz to 14,600MHz at a single RF
output. A series of frequency dividers with a differential frequency
output allows operation from 57MHz to 14,600MHz. Analog and
digital power supplies for the PLL circuitry range from 3.15V to
3.45V, and the VCO supplies are between 4.75V and 5.25V.
The ADF5611 has an integrated VCO with a fundamental frequency
of 3650MHz to 7300MHz. These frequencies are internally doubled
and routed to the RFOUT pin. An additional differential output
allows the doubled VCO frequency to be divided by 1, 2, 4, 8, 16,
32, 64, or 128, allowing the user to generate RF output frequencies
as low as 57MHz. A simple 3- or 4-wire serial port interface (SPI)
provides control of all on-chip registers. To conserve power, this
divider block can be disabled when not needed through the SPI.
Likewise, the output power for both the single-ended output and the
differential output are programmable.
The integrated phase detector and Δ-Σ modulator, capable of operating
at up to 100MHz, permit wide loop bandwidths and fast
frequency tuning with a typical spurious level of −105dBc.
With a VCO open-loop phase noise at an 100kHz offset from
−115dBc/Hz at a 7.3GHz RFOUT to −109dBc/Hz at a 14.6GHz
RFOUT, the ADF5611 is equipped to minimize blocker effects and
to improve receiver sensitivity and transmitter spectral purity. The
low phase noise floor eliminates any contribution to modulator and
mixer noise floor in transmitter applications.
APPLICATIONS
- Military and defense
- Test equipment
- Clock generation
- Wireless infrastructure
- Satellite and very small aperture terminals (VSATs)
- Microwave radios
