HMC701LP6CE Datasheet, PDF (31/46 Pages) Hittite Microwave Corporation – 8 GHz 16-Bit Fractional-N Synthesizer

v03.0709
HMC701LP6CE
8 GHz 16-Bit Fractional-N Synthesizer
Single Step Ramp Mode
A Single Step 1-Way Ramp is shown in Figure 28. In this mode, a trigger is required for each step of the ramp. Single
step will function in either 1-Way or 2-Way ramps. Similar to autosweep, the ramp_busy flag will go high on the first
trigger, and will stay high until the nth trigger. The n+1 trigger will cause the ramp to jump to the start frequency in
1-way ramp mode. The n+2 trigger will restart the 1-way ramp.
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Figure 28. Single Step Ramp Mode
The user should be aware that the synthesized ramp is subject to normal phase locked loop dynamics. If the loop
bandwidth in use is much wider than the rate of the steps then the locking will be very fast and the ramp will have a
staircase shape. If the update rate is higher than the loop bandwidth, as is normally the case, then the loop will not
fully settle before a new frequency step is received. Hence the swept output will have a small lag and will sweep in a
near continuous fashion.
MAIN SERIAL PORT
The HMC701LP6CE features a four wire serial port for simple communication with the host controller. Register types
may be Read Only, Write Only, Read/Write or Strobe, as described in the registers descriptions. The synthesizer also
features an auxiliary 3-wire serial port, known as the VCO Serial Port. The VCO Serial Port is a write only interface
from the synthesizer to an optional switched resonator VCO that supports 3-wire serial port control.
Typical main serial port operation can be run with SCLK at speeds up to 50 MHz. Serial port registers are described
in the section REGISTER MAP.
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[1] Phase-Error Measurement and Compensation in PLL Frequency Synthesizers for FMCW, Sensors—I: Context and Application, Pichler, Stelzer,
Member, IEEE, Seisenberger, and Vossiek, IEEE Transactions on Circuits and Systems—I, VOL. 54, No. 5, May 2007
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