MB1507
PHASE DETECTOR OUTPUT WAVEFORM (FC=High)
f
r
f
P
LD
H
Z
D
O
L
f >f
f =f
f <f
f <f
f <f
r p
r
p
r
p
r
p
r
p
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 f >f or f <f , spike might not appear depending upon charge pump characteristics.
r
p
r
p
ANALOG SWITCH
ON/OFF of analog switch is controlled by LE input signal. When the analog switch is ON, internal charge pump output (D ) is connected to BISW pin.
O
When the analog switch is OFF, BI-SW pin is set to high-impedance state.
LE
Analog Switch
H(Changing the divide ratio of internal prescaler)
L(Normal operating mode)
ON
OFF
When an analog switch is inserted between LP1 and LP2, faster lock up time is achieved to reduce LPF time constant during PLL channel switching.
D
O
CHARGE PUMP
LPF-1
LPF-2
V
CO
BISW
ANALOG SW
(CONTROL SIGNAL LE)
7
FUJITSU [ FUJITSU ]
