Datasheet

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BOARD DESIGN CONSIDERATIONS
Grounding
Supply Decoupling
Exposed Thermal Pad
ADS6245 , ADS6244
ADS6243 , ADS6242
SLAS542A – MAY 2007 – REVISED JULY 2007
A single ground plane is sufficient to give optimum performance, provided the analog, digital and clock sections
of the board are cleanly partitioned. Refer to the EVM User Guide (SLAU196 ) for more layout details.
As the ADS624X already includes internal decoupling, minimal external decoupling can be used without loss in
performance. Note that the decoupling capacitors can help to filter external power supply noise, so the optimum
number of decoupling capacitors would depend on actual application.
It is recommended to use separate supplies for the analog and digital supply pins to isolate digital switching
noise from sensitive analog circuitry. In case only a single 3.3V supply is available, it should be routed first to
AVDD. It can then be tapped and isolated with a ferrite bead (or inductor) with decoupling capacitor, before being
routed to LVDD.
For best thermal performance, it is necessary to solder the exposed pad at the bottom of the package to a
ground plane using multiple vias. For detailed information, see application notes QFN Layout Guidelines
(SLOA122 A) and QFN/SON PCB Attachment (SLUA271 A).
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Product Folder Link(s): ADS6245 ADS6244 ADS6243 ADS6242