AD4360-8 Datasheet, PDF (18/24 Pages) Analog Devices – Integrated Synthesizer and VCO

ADF4360-8
Hardware Power-Up/Power-Down
If the part is powered down via the hardware (using the CE pin)
and powered up again without any change to the N counter
register during power-down, the part locks at the correct fre-
quency, because the part is already in the correct frequency
band. The lock time depends on the value of capacitance on the
CN pin, which is <15 ms for 10 µF capacitance. The smaller
capacitance of 440 nF on this pin enables lock times of <600 µs.
The N counter value cannot be changed while the part is in
power-down, since the part may not lock to the correct
frequency on power-up. If it is updated, the correct program-
ming sequence for the part after power-up is the R counter
latch, followed by the control latch, and finally the N counter
latch, with the required interval between the control latch and N
counter latch, as described in the Initial Power-Up section.
Software Power-Up/Power-Down
If the part is powered down via the software (using the control
latch) and powered up again without any change to the N
counter latch during power-down, the part locks at the correct
frequency, because the part is already in the correct frequency
band. The lock time depends on the value of capacitance on the
CN pin, which is <15 ms for 10 µF capacitance. The smaller
capacitance of 440 nF on this pin enables lock times of <600 µs.
The N counter value cannot be changed while the part is in
power-down, because the part may not lock to the correct
frequency on power-up. If it is updated, the correct program-
ming sequence for the part after power-up is to the R counter
latch, followed by the control latch, and finally the N counter
latch, with the required interval between the control latch and N
counter latch, as described in the Initial Power-Up section.
Rev. A | Page 18 of 24