Mobile Communications
High-Performance
13 GHz PLL Synthesizer
The ADF4159 from Analog Devices is a 13 GHz PLL synthesizer that achieves a phase detector operating frequency
of 110 MHz while simultaneously consuming
less than 100 m W of power. The device contains a 25-bit fixed modulus as well as on-chip
functionality to generate highly linear ramp
profiles, making it an ideal solution for fre-quency-modulated continuous-wave (FMCW)
radar applications, including automotive radar
systems. The ADF4159 is also ideal for microwave point-to-point (PtP) systems, communications infrastructure, instrumentation and test
equipment.
ADI’s ADF4159 fractional-N PLL synthesizer consists of a low-noise digital phase
frequency detector (PFD), precision charge
pump and a programmable reference divider.
It can be used to implement frequency shift
keying (FSK) and phase shift keying (PSK)
modulation. There are also a number of frequency sweep modes available that generate
various waveforms, such as sawtooth and triangular waveforms. The functional block diagram
of the ADF4159 is shown in Figure 1.
APPLICATIONS
ADI’s high-performance ADF4159 PLL
features industry-leading phase noise perfor-
mance of −223 dBc/Hz and 1/f noise perfor-
mance of −
120 dBc/Hz. The very high maxi-
mum PFD frequency allows for very good in-
band phase noise while it also allows for very
wide loop bandwidths if extremely fast settling
time is required.
The ADF4159 is powered by a 2.7 to 3. 3 V
analog power supply and a 1.8 V digital power
supply. The typical current drawn by the part
is 33 mA.
RAMP GENERATION
ADI’s ADF4159 PLL can generate a variety
of frequency sweeps or ramps. The ADF4159
is initially programmed once and will contin-
ANALOG DEVICES
Norwood, MA
