zl30406 Zarlink Semiconductor, zl30406 Datasheet - Page 5

• Manufacturer Part Number: zl30406
• Description: Sonet/sdh Clock Multiplier Pll
• Manufacturer: Zarlink Semiconductor

1.0
The ZL30406 is an analog phased-locked loop which provides rate conversion and jitter attenuation for
SONET/SDH OC-48/STM-16, OC-12/STM-4 and OC-3/STM-1 applications. A functional block diagram of the
ZL30406 is shown in Figure 1 and a brief description is presented in the following sections.
1.1
The Frequency/Phase Detector compares the frequency/phase of the input reference signal with the feedback
signal from the Frequency Divider circuit and provides an error signal corresponding to the frequency/phase
difference between the two. This error signal is passed to the Loop Filter circuit and averaged to control the
VCO frequency.
1.2
The Loop Filter is a low pass filter. This low pass filter ensures that the network jitter requirements are met for an
input reference frequency of 19.44 MHz. The corner frequency of the Loop Filter is configurable with an external
capacitor and resistor connected to the LPF pin and ground as shown below.
1.3
The voltage-controlled oscillator (VCO) receives the filtered error signal from the Loop Filter, and based on the
voltage of the error signal, generates a primary frequency. The VCO output is connected to the Output Interface
Circuit that divides VCO frequency and buffers generated clocks.
Frequency/Phase Detector
Loop Filter
VCO
Functional Description
Figure 3 - External Loop Filter
Zarlink Semiconductor Inc.
Internal Loop
ZL30406
Filter
ZL30406
5
LPF
(for 14 kHz PLL bandwidth)
RF=8.2 k:, CF=470 nF
R
C
F
F
Data Sheet