Data Sheet
ADF4360-3
R COUNTER LATCH
N 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.
With (C2, C1) = (1, 0), the N counter latch is programmed.
Table 8 shows the input data format for programming the
N counter latch.
R Counter
A Counter Latch
R1 to R14 set the counter divide ratio. The divide range is 1
(00......001) to 16383 (111......111).
A5 to A1 program the 5-bit A counter. The divide range is 0
(00000) to 31 (11111).
Antibacklash Pulse Width
Reserved Bits
DB16 and DB17 set the antibacklash pulse width.
Lock Detect Precision
DB7 is a spare bit that is reserved. It should be programmed to 0.
B Counter Latch
DB18 is the lock detect precision bit and 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.
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.
Test Mode Bit
DB19 is the test mode bit (TMB) 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.
CP Gain
DB21 of the N counter latch in the ADF4360 family is the
charge pump gain bit. When this 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 will always reflect the latest value written to it,
whether this is through the control latch or the N counter latch.
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, but 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).
Divide-by-2
DB22 is the divide-by-2 bit. When set to 1, the output divide-by-2
function is chosen. When it is set to 0, normal operation occurs.
Divide-by-2 Select
Reserved Bits
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 will need a value of N = 8,000 to
generate 800 MHz. With the divide-by-2 select bit high, the user
may keep N = 4,000.
DB23 to DB22 are spare bits that are reserved. They should be
programmed to 0.
Rev. C | Page 19 of 24
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