Isolating digital and analog grounds in Kinetis K60 Series of NXP

Thread Starter

HASEEB FAYYAZ ABBASI

Joined Dec 4, 2011
2
How will it be ensured that digital and analog grounds are isolated for K60 series controller when power supplies for analog and digital supplies are separate. Diagram is attached for clarity. How to connect these two grounds with each other? What circuitry will be needed to ensure these two grounds does not effect each other when they are connected?Capture.PNG
 

Danko

Joined Nov 22, 2017
828
Hardware
Grounds and power supplies
  • We strongly recommend separate regulators for digital VDD and analog VDDA supplies, though they need to set to the same level.
  • No inductive coupling between VSS and VSSA
    • Use isolated digital and analog planes resistively coupled (0W) at a “starpoint” directly underneath VSSA pin/ball.
  • There should be two ground planes, one for digital and a second for analog.
  • The board designer needs to avoid overlap of the digital ground plane with the analog ground plane
  • Analog signals and analog power should remain closely coupled with the analog ground plane.
  • Separate regulators for digital and analog supplies
  • Even better to provide an independent regulator for VREFH
  • Large “tank” caps at the regulator output for stability, decoupling caps of various values very close to the DUT. 10uF capacitors should be placed on power inputs (VDD, VDDAD, VREFH)
LINK to article
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EDIT:
Grounding in mixed-signal systems demystified, Part 1:
Grounding in mixed-signal systems demystified, Part 2:
 
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