ADF4360-2_15 Datasheet, PDF (19/24 Pages) Analog Devices – Integrated Synthesizer and VCO

Data Sheet
N COUNTER LATCH
With (C2, C1) = (1, 0), the N counter latch is programmed.
Table 8 shows the input data format for programming the
N counter latch.
A Counter Latch
A5 to A1 program the 5-bit A counter. The divide range is
0 (00000) to 31 (11111).
Reserved Bits
DB7 is a spare bit that is reserved. It should be programmed to 0.
B Counter Latch
B13 to B1 program the B counter. The divide range is 3
(00.....0011) to 8191 (11....111).
Overall Divide Range
The overall divide range is defined by ((P × B) + A), where P is
the prescaler value.
CP Gain
DB21 of the N counter latch in the ADF4360 family is the
charge pump gain bit. When this bit is programmed to 1,
Current Setting 2 is used. When programmed to 0, Current
Setting 1 is used. This bit can also be programmed through DB10
of the control latch. The bit always reflects the latest value written to
it, whether through the control latch or the N counter latch.
Divide-by-2
DB22 is the divide-by-2 bit. When set to 1, the output divide-by-2
function is chosen. When set to 0, normal operation occurs.
Divide-by-2 Select
DB23 is the divide-by-2 select bit. When programmed to 1, the
divide-by-2 output is selected as the prescaler input. When set
to 0, the fundamental is used as the prescaler input. For
example, using the output divide-by-2 feature and a PFD
frequency of 200 kHz, the user needs a value of N = 10,000 to
generate 1000 MHz. With the divide-by-2 select bit high, the
user can keep N = 5,000.
ADF4360-2
R COUNTER LATCH
With (C2, C1) = (0, 1), the R counter latch is programmed.
Table 9 shows the input data format for programming the
R counter latch.
R Counter
R1 to R14 set the counter divide ratio. The divide range is
1 (00......001) to 16383 (111......111).
Antibacklash Pulse Width
DB16 and DB17 set the antibacklash pulse width.
Lock Detect Precision
DB18 is the lock detect precision bit. This bit sets the number of
reference cycles with less than 15 ns phase error for entering the
locked state. With LDP at 1, five cycles are taken; with LDP at 0,
three cycles are taken.
Test Mode Bit (TMB)
DB19 is the test mode bit and should be set to 0. With TMB = 0,
the contents of the test mode latch are ignored and normal
operation occurs as determined by the contents of the control
latch, R counter latch, and N counter latch. Note that test modes
are for factory testing only and should not be programmed by
the user.
Band Select Clock
These bits set a divider for the band select logic clock input. The
output of the R counter is by default the value used to clock the
band select logic. If this value is too high (>1 MHz), a divider
can be switched on to divide the R counter output to a smaller
value (see Table 9).
Reserved Bits
DB23 to DB22 are spare bits that are reserved. They should be
programmed to 0.
Rev. C | Page 19 of 24