SBAS561C June 2012 – January 2017 ADS131E04 , ADS131E06 , ADS131E08
PRODUCTION DATA.
TI recommends employing best design practices when laying out a printed-circuit board (PCB) for both analog and digital components. This recommendation generally means that the layout separates analog components (such as ADCs, amplifiers, references, digital-to-analog converters (DACs), and analog MUXs) from digital components (such as microcontrollers, complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), radio frequency (RF) transceivers, universal serial bus (USB) transceivers, and switching regulators). An example of good component placement is shown in Figure 68. Although Figure 68 provides a good example of component placement, the best placement for each application is unique to the geometries, components, and PCB fabrication capabilities employed. That is, there is no single layout that is perfect for every design and careful consideration must always be used when designing with any analog component.
The following outlines some basic recommendations for the layout of the ADS131E0x to get the best possible performance of the ADC. A good design can be ruined with a bad circuit layout.
Figure 69 shows an example layout of the ADS131E0x requiring a minimum of two PCB layers. The example circuit is shown for either a unipolar analog supply connection or a bipolar analog supply connection. In this example, polygon pours are used as supply connections around the device. If a three- or four-layer PCB is used, the additional inner layers can be dedicated to route power traces. The PCB is partitioned with analog signals routed from the left, digital signals routed to the right, and power routed above and below the device.