MB1511 Datasheet, PDF (8/15 Pages) Fujitsu Component Limited. – Serial Input PLL Frequency Synthesizer

MB1511
4. Phase Characteristics
FC pin is provided to change phase characteristics of phase comparator. Characteristics of internal charge pump
output level (DO), phase comparator output level (φR, φP) are reversed depending upon FC pin input level. Also,
monitor pin (fOUT) output level of phase comparator is controlled by FC pin input level. The relation between outputs
(DO, φR, φP) and FC input level are shown below.
FC : “H” or open
FC : “L”
DO
φR
φP
fOUT
DO
φR
φP
fOUT
fr > fp
H
L
L
(fr)
L
H
Z
(fp)
fr = fp
Z
L
Z
(fr)
Z
L
Z
(fp)
fr < fp
L
H
Z
(fr)
H
L
L
(fp)
Note: Z = (High impedance)
Depending upon VCO characteristics, FC pin should be set accordingly:
• When VCO characteristics are like (1), FC
should be set High or open circuit; When
VCO characteristics are like (2), FC should
be set Low.
(1)
(2)
VCO Input Voltage
8