MB1503 Fujitsu Media Devices, MB1503 Datasheet - Page 9

• Manufacturer Part Number: MB1503
• Description: LOW-POWER PLL FREQUENCY SYNTHESIZER
• Manufacturer: Fujitsu Media Devices

Phase comparator output waveform (FC = High)
Analog switch
The LE signal turns the analog switch on or off. When the analog switch is turned on, the charge pump output (D
the BiSW pin. When it is turned off, the BiSW pin is in the high-impedance state.
The LPF time constant can be decreased by inserting an analog switch between LPF1 and LPF2. This decreases the lock-up time
when the PLL channel is changed.
Notes: 1. Phase difference detection range: –2 to +2
When LE = high (when the divide ratio of the internal divider is changed): Analog switch = on
When LE = low (normal operating mode): Analog switch = off
D
LD
f
f
O
R
P
2. Spike appearance depends on the charge pump characteristics. Also, the spike is output to diminish
3. When f
4. LD is low when the phase difference is tw or more. LD is high when the phase difference is tw or less for
dead band.
three or more cycles (when f
f
R
(Control signal LE)
> f
R
> f
P
CHP
H
P
or f
R
< f
f
P
R
, a spike might not appear depending on the charge pump characteristics.
= f
P
D
O
OSCIN
Z
Analog
switch
= 12.8MHz, tw = 625 to 1,250ns).
LPF–1
f
R
< f
P
L
BiSW
f
R
< f
P
LPF–2
f
R
< f
P
VCO
O
) is output through
MB1503
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