12

CDCLVC1102, CDCLVC1103, CDCLVC1104

CDCLVC1106, CDCLVC1108, CDCLVC1110, CDCLVC1112

SCAS895B – MAY 2010 – REVISED FEBRUARY 2017

www.ti.com

Product Folder Links: CDCLVC1102 CDCLVC1103 CDCLVC1104 CDCLVC1106 CDCLVC1108 CDCLVC1110

CDCLVC1112

Submit Documentation Feedback

Copyright © 2010–2017, Texas Instruments Incorporated

Typical Application (continued)

9.2.3 Application Curves

Figure 11. CDCLVC11xx Reference Phase Noise 26 fs

(12 kHz to 20 MHz)

Figure 12. CDCLVC11xx Output Phase Noise 86 fs

(12 kHz to 20 MHz)

The low additive jitter of the CDCLVC11xx can be shown in the previous application example. The low-noise

100-MHz XO with 26-fs RMS jitter drives the CDCLVC11xx, resulting in 86-fs RMS jitter when integrated from 12

kHz to 20 MHz. The resultant additive jitter is a low 82-fs RMS for this configuration.

10 Power Supply Recommendations

High-performance clock buffers are sensitive to noise on the power supply, which can dramatically increase the

additive jitter of the buffer. Thus, it is essential to reduce noise from the system power supply, especially when

the jitter and phase noise is critical to applications.

Filter capacitors are used to eliminate the low-frequency noise from the power supply, where the bypass

capacitors provide the very low impedance path for high-frequency noise and guards the power supply system

against induced fluctuations. These bypass capacitors also provide instantaneous current surges as required by

the device and should have low equivalent series resistance (ESR). To properly use the bypass capacitors, they

must be placed very close to the power-supply terminals and laid out with short loops to minimize inductance. TI

recommends adding as many high-frequency (for example, 0.1 µF) bypass capacitors, as there are supply

terminals in the package. TI recommends, but does not require, inserting a ferrite bead between the board power

supply and the chip power supply that isolates the high-frequency switching noises generated by the clock buffer;

these beads prevent the switching noise from leaking into the board supply. It is imperative to choose an

appropriate ferrite bead with very low DC resistance to provide adequate isolation between the board supply and

the chip supply, as well as to maintain a voltage at the supply terminals that is greater than the minimum voltage

required for proper operation.