cxa3516r Sony Electronics, cxa3516r Datasheet - Page 48

• Manufacturer Part Number: cxa3516r
• Description: 3-channel 8-bit 165msps A/d Converter Amplifier Pll
• Manufacturer: Sony Electronics

• Charge pump (CP)
The VCO oscillation frequency is that at the Point A in the diagram.
• Loop filter (LPF)
• VCO
The charge pump sets charge pump current to flow for the amount of time corresponding to the pulse width
output from the phase detector. The phase detector gain is determined by the charge pump current.
The amount of current can be varied by using a control register.
This IC is used to set the charge pump current value according to the VCO oscillation frequency as given
below.
[CP Setting Matrix]
The control voltage input to the VCO is the pulse current output from the charge pump circuit that is
smoothed by an integrating circuit (loop filter). The resistor and capacitor values of the integrating circuit are
as follows. (For the circuit configuration, see the application circuit.)
For the resistor and capacitors, use a metal film chip resistor with little temperature variation and ceramic
chip capacitors. In particular, the 0.33µF capacitor should be equivalent to high dielectric constant series
capacitor type B or better.
(Electrostatic capacitance change ratio ±10%: T = –25 to +85°C)
In case of using any resistors or capacitors except those given above, it is not guaranteed.
The VCO oscillation frequency range covers from 40MHz to 165MHz.
Register: Charge Pump Bit2
Register: Charge Pump Bit1
Register: Charge Pump Bit0
VCO oscillation frequency: CP setting values
Charge pump current
C1 = 0.33µF
C2 = 330pF
R1 = 3.3k
110MHz to 140MHz: 400µA
140MHz to 155MHz: 500µA
155MHz to 165MHz: 600µA
40MHz to 85MHz:
85MHz to 110MHz: 300µA
200µA
100µA
0
0
0
200µA
0
0
1
– 48 –
300µA
0
1
0
400µA
0
1
1
500µA
1
0
0
600µA
1
0
1
700µA
1
1
0
CXA3516R
800µA
1
1
1