MB1511 Datasheet, PDF (9/15 Pages) Fujitsu Component Limited. – Serial Input PLL Frequency Synthesizer

MB1511
Phase comparator output waveforms are shown below.
fr
fp
LD
H
DO
fr > fp
Z
fr = fp
L
fr < fp
fr < fp
fr < fp
Notes: Phase difference detection range: –2π to +2π
Spike appearance depends on charge pump characteristics. Also, the spike is output in order to diminish dead band.
When fr>fp or fr<fp, spike might not appear depending upon charge rump characteristics.
5. Analog Switch
ON/OFF of analog switch is controlled by LE input signal. When the analog switch is ON, internal charge pump
output (DO) is connected to BISW pin. When the analog switch is OFF, BISW pin is set to high-impedance state.
LE
H (Changing the divide ratio of internal prescaler)
L (Normal operationg mode)
Analog Switch
ON
OFF
When an analog switch is inserted between LP1 and LP2, faster lock up times is achieved to reduce LPF time
constant during PLL channal switching.
DO
CHARGE
PUMP
LPF-1
(CONTROL SIGNAL LE)
ANALOG
SW
BISW
LPF-2
VCO
9