SCAS887B September 2009 – January 2016 CDCLVP2106
PRODUCTION DATA.
- 1 Features
- 2 Applications
- 3 Description
- 4 Revision History
- 5 Pin Configuration and Functions
-
6 Specifications
- 6.1 Absolute Maximum Ratings
- 6.2 ESD Ratings
- 6.3 Recommended Operating Conditions
- 6.4 Thermal Information
- 6.5 Electrical Characteristics: LVCMOS Input, at VCC = 2.375 V to 3.6 V
- 6.6 Electrical Characteristics: Differential Input, at VCC = 2.375 V to 3.6 V
- 6.7 Electrical Characteristics: LVPECL Output, at VCC = 2.375 V to 2.625 V
- 6.8 Electrical Characteristics: LVPECL Output, at VCC = 3 V to 3.6 V
- 6.9 Timing Requirements, at VCC = 2.375 V to 2.625 V
- 6.10 Timing Requirements, at VCC = 3 V to 3.6 V
- 6.11 Typical Characteristics
- 7 Parameter Measurement Information
- 8 Detailed Description
- 9 Application and Implementation
- 10Power Supply Recommendations
- 11Layout
- 12Device and Documentation Support
- 13Mechanical, Packaging, and Orderable Information
10 Power Supply Recommendations
10.1 Power-Supply Filtering
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 jitter/phase noise is very 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 guard the power-supply system against the 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 pins 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 pins 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 driver; these beads prevent the switching noise from leaking into the board supply. Choose an appropriate ferrite bead with very low dc resistance because it is imperative to provide adequate isolation between the board supply and the chip supply, as well as to maintain a voltage at the supply pins that is greater than the minimum voltage required for proper operation.
Figure 23 shows this recommended power-supply decoupling method.
Figure 23. Power-Supply Decoupling