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2
PCB Design and Performance
2.1
PCB Layout
PCB Design and Performance
1.3.1
Related Documentation from Texas Instruments
The following documents provide information regarding Texas Instrument integrated circuits used in the
assembly of the DAC8554EVM. The latest revisions of these documents are available from the TI web site
at
Data Sheet
Literature Number
DAC8854 Datasheet
REF02 Datasheet
OPA627 Datasheet
OPA2132 Datasheet
This section discusses the layout design of the DAC8554EVM PCB, describing the physical and
mechanical characteristics of the EVM as well as a brief description of the demonstration board test
performance procedures performed. The list of components used in this evaluation module is also
included.
The DAC8554EVM is designed to preserve the performance quality of the DAC8554, the device under
test (DUT), as specified in the data sheet. In order to take full advantage of the EVM capabilities, use care
during the schematic design phase to properly select the right components and to build the circuit
correctly. The circuit design should include adequate bypassing, identifying and managing the analog and
digital signals, and understanding the components' electrical and mechanical attributes.
The primary design concerns during the layout process are optimal component placement and proper
signal routing. Place the bypass capacitors as close as possible to the device pins, and properly separate
the analog and digital signals from each other. In the layout process, carefully consider the placement of
the power and ground planes. A solid plane is ideal, but because of its greater cost, a split plane can
sometimes be used satisfactorily. When considering a split plane design, analyze the component
placement and carefully split the board into its analog and digital sections starting from the DUT. The
ground plane plays an important role in controlling the noise and other effects that otherwise contribute to
the error of the DAC output. To ensure that the return currents are handled properly, route the appropriate
signals only in their respective sections, meaning that the analog traces should only lay directly above or
below the analog section and the digital traces in the digital section. Minimize trace length, but use the
largest possible trace width allowable within the design. These design practices are illustrated in
through
The DAC8554EVM 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 is
1,5748mm (0.062in).
through
show the individual artwork layers.
Note:
Board layouts are not to scale. These are intended to show how the board is laid out; they
are not intended to be used for manufacturing DAC8554EVM PCBs.
DAC8554EVM User's Guide
4
SBAU121 – January 2006