adf4206 Analog Devices, Inc., adf4206 Datasheet - Page 19

• Manufacturer Part Number: adf4206
• Description: Dual Rf Pll Frequency Synthesizers
• Manufacturer: Analog Devices, Inc.

RF2 Prescaler Value
P6 in the RF2 AB counter latch sets the RF2 prescaler value.
See Figure 29.
RF2 Power-Down
P7 in Figure 29 is the power-down bit for the RF2 side.
RF SECTION (RF1)
Programmable RF1 Reference (R) Counter
If Control Bit C2 and Control Bit C1 are 1 and 0, the data is
transferred from the input shift register to the 14-bit RF1 R
counter. Figure 30 shows the input shift register data format for
the RF1 R counter and the divide ratios that are possible.
RF1 Phase Detector Polarity
P9 sets the RF1 phase detector polarity. When the RF1 VCO
characteristics are positive this is set to 1. When negative it is set
to 0. See Figure 30.
RF1 Charge Pump Three-State
P10 puts the RF1 charge pump into three-state mode when
programmed to a 1. It is set to 0 for normal operation.
See Figure 30.
RF1 Program Modes
Figure 28 and Figure 30 show how to set up the program modes
in the ADF420x family.
Rev. A | Page 19 of 24
RF1 Charge Pump Currents
Bit P13 programs the current setting for the RF1 charge pump.
See Figure 30.
Programmable RF1 AB Counter
If Control Bit C2 and Control Bit C1 are 1 and 1, then the data
in the input register is used to program the RF1 AB counter.
The AB counter is a 6-bit swallow counter (A counter) and
11-bit programmable counter (B counter). Figure 31 shows the
input register data format for programming the RF1 AB counter
and the divide ratios that are possible.
RF1 Prescaler Value
P14 in the RF1 A, B counter latch sets the RF1 prescaler value.
See Figure 31.
RF1 Power-Down
Setting P16 in the RF1 AB counter high powers down RF1 side.
RF Fast Lock
The fast lock feature improves the lock time of the PLL. It
increases charge pump current to a maximum for a time.
Activate fast lock of the ADF420x family by setting P13 in the
reference counter high and setting the fast lock switch on using
MUXOUT. Switching in an external resistor using MUXOUT
compensates the loop dynamics for the effect of increasing
charge pump current. Setting P13 low removes the PLL from
fast lock mode.
ADF4206/ADF4208