Texas Instruments DAC9881EVM - DAC9881 Evaluation Module DAC9881EVM DAC9881EVM 데이터 시트
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DAC9881EVM
PCB Design and Performance
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Figure 1. Block Diagram
2
PCB Design and Performance
This section discusses the layout design of the printed-circuit board (PCB), the physical and mechanical
characteristics of the EVM, and a brief description of the EVM test performance procedure. The list of
components used on this evaluation module also is included in this section.
characteristics of the EVM, and a brief description of the EVM test performance procedure. The list of
components used on this evaluation module also is included in this section.
2.1
PCB Layout
The DAC9881EVM is designed to preserve the performance quality of the DAC as specified in the data
sheet. To take full advantage of the EVM's capabilities, use care during the schematic design phase to
properly select the right components and to build the circuit correctly. The circuit must include adequate
bypassing, identifying, and managing the analog and digital signals, and understanding the components
electrical and mechanical attributes.
sheet. To take full advantage of the EVM's capabilities, use care during the schematic design phase to
properly select the right components and to build the circuit correctly. The circuit must include adequate
bypassing, identifying, and managing the analog and digital signals, and understanding the components
electrical and mechanical attributes.
The main design concern during the layout process is the optimal placement of components and the
proper routing of signals. Place the bypass capacitors as close as possible to the pins and be sure to
route the analog and digital signals away from each other. A solid ground plane is preferred. 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 reducing
noise that contributes 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, the analog traces should only lay
directly above or below the analog section and the digital traces in the digital section. Minimize the length
of the traces but use the largest possible trace width allowable in the design. These design practices were
applied to the DAC9881EVM PCB.
proper routing of signals. Place the bypass capacitors as close as possible to the pins and be sure to
route the analog and digital signals away from each other. A solid ground plane is preferred. 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 reducing
noise that contributes 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, the analog traces should only lay
directly above or below the analog section and the digital traces in the digital section. Minimize the length
of the traces but use the largest possible trace width allowable in the design. These design practices were
applied to the DAC9881EVM PCB.
The DAC9881EVM board is constructed on a four-layer PCB using a copper-clad FR-4 laminate material.
The PCB has a dimension of 43,18 mm (1.70 inch) × 82,55 mm (3.25 inch), and the board thickness is
1,57 mm (0.062 inch).
The PCB has a dimension of 43,18 mm (1.70 inch) × 82,55 mm (3.25 inch), and the board thickness is
1,57 mm (0.062 inch).
through
show the individual artwork layers.
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DAC9881 Evaluation Module
SLAU279A – March 2009 – Revised November 2009
Copyright © 2009, Texas Instruments Incorporated