CXA3106Q
Description of Block Diagram
Sync Input
Sync signals in the range of 10 to 100kHz can be input. Input supports both positive and negative polarity.
PECL input can also be a single input.
When SYNC is positive polarity, the clock is regenerated in synchronization with the rising edge of the sync signal.
When SYNC is negative polarity, the clock is regenerated in synchronization with the falling edge of the sync signal.
VCO oscillation stops when there is no sync input.
0
1
Register: SYNC POL
SYNC input polarity
Negative
Positive
Phase Detector
The phase detector operates at the sync input frequency of 10 to 100kHz. The PD input polarity should be
set to the default PD POL = 1. Phase comparison is performed at the edges.
The input circuit of the phase detector does not contain a hysteresis circuit, so the waveform must be shaped
at the front end of the CXA3106Q when inputting a noisy signal.
The phase detector HOLD signal is supplied by TTL. (See the HOLD Timing Chart.)
The PLL UNLOCK signal is output by an open collector.
(See the UNLOCK Timing Chart.)
Charge Pump
The gain (I, I/4, I/16) can be varied by changing the charge pump current using 2 bits of control register.
0
0
Register: C.Pump bit 1
Register: C.Pump bit 0
Charge pump current
1
0
1
1
400µA
1600µA
100µA
LPF
This is a loop filter comprised of the external capacitors and resistor.
Be sure to use metal film resistors with little temperature variation and a temperature-compensated capacitor.
In particular, the 0.33µF capacitor should be equivalent to Murata's high dielectric constant series capacitor
type B or better. (electrostatic capacitance change ratio ±10%: T = –25 to +85°C)
VCO
The VCO oscillator frequency covers from 40 to 120MHz.
VCO Rear-end Counter
The VCO output is frequency divided to 1/1, 1/2 or 1/4 by switching 2 bits of control register.
The operating range can be expanded to 10 to 120MHz by combining the counter with a VCO frequency divider.
0
0
Register: DIV 1, 2, 4 bit 1
Register: DIV 1, 2, 4 bit 0
Counter frequency divisions
1
0
1
1
1/2
1/4
1/1
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SONY [ SONY CORPORATION ]
