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1.3.1 Related Documentation from Texas Instruments
2 PCB Design and Performance2.1 PCB Layout
PCB Design and Performance
The following documents provide information regarding Texas Instrument integrated circuits used in theassembly of the DAC8555EVM. The latest revisions of these documents are available from the TI web siteat http://www.ti.com.
Data Sheet Literature Number
DAC8555 SLAS475
REF02 SBVS003
OPA627 SBOS165
OPA2132 SBOS054
This section discusses the layout design of the DAC8555EVM PCB, describing the physical andmechanical characteristics of the EVM as well as a brief description of the demonstration board testperformance procedures performed. The list of components used in this evaluation module is alsoincluded.
The DAC8555EVM is designed to preserve the performance quality of the DAC8555, the device undertest (DUT), as specified in the data sheet. In order to take full advantage of the EVM capabilities, use careduring the schematic design phase to properly select the right components and to build the circuitcorrectly. The circuit design should include adequate bypassing, identifying and managing the analog anddigital signals, and understanding the components' electrical and mechanical attributes.
The primary design concerns during the layout process are optimal component placement and propersignal routing. Place the bypass capacitors as close as possible to the device pins, and properly separatethe analog and digital signals from each other. In the layout process, carefully consider the placement ofthe power and ground planes. A solid plane is ideal, but because of its greater cost, a split plane cansometimes be used satisfactorily. When considering a split plane design, analyze the componentplacement and carefully split the board into its analog and digital sections starting from the DUT. Theground plane plays an important role in controlling the noise and other effects that otherwise contribute tothe error of the DAC output. To ensure that the return currents are handled properly, route the appropriatesignals only in their respective sections, meaning that the analog traces should only lay directly above orbelow the analog section and the digital traces in the digital section. Minimize trace length, but use thelargest possible trace width allowable within the design. These design practices are illustrated in Figure 2through Figure 8 .
The DAC8555EVM board is constructed on a four-layer PCB using a copper-clad FR-4 laminate material.The PCB has a dimension of 43,1800mm (1.7000in) by 82,5500mm (3.2500in), and the board thickness is1,5748mm (0.062in). Figure 3 through Figure 7 show the individual artwork layers.
Note: Board layouts are not to scale. These are intended to show how the board is laid out; theyare not intended to be used for manufacturing DAC8555EVM PCBs.
6DAC8555EVM User's Guide SLAU204 – December 2006Submit Documentation Feedback