Appendix B: Stack-Ups; Reference Design Stack-Ups - Nvidia Jetson TX2 Manual

17.0 APPENDIX B: STACK-UPS

17.1 Reference Design Stack-Ups

17.1.1 Importance of Stack-Up Definition
Stack-ups define the number and order of Board layers. Stack-up definition is critical to the follow ing design:
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Circuit routability
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Signal quality
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Cost
17.1.2 Impact of Stack-Up Definition on Design
Stack-Up Im pact on Circuit Routability
If there are insufficient layers to maintain proper signal spacing, prevent discontinuities in reference planes, obstruct flo w of
sufficient current, or avoid extra vias, circuit routing can become unnecessarily complex. Layer count must be minimally
appropriate for the circuit.
Stack-Up Im pact on Signal Quality
Both layer count and layer order impact signal integrity. Proper inter-signal spacing must be achievable. Via count for critical
signals must be minimized. Current commensurate w ith the performance of the board must be carried. Critical signals must be
adjacent to major and minor reference planes, and adhere to proximity constraints w ith respect to those planes. The
recommended NVIDIA stack-ups achieve these requirements for the signal speeds supported by the board.
Stack-Up Im pact on Cost
While defining extra layers can facilitate excellent signal integrity, current handling capability and routability, extra layers can
impede the goal of hitting cost targets. The art of stack-up definition is achieving all technical and reliability circuit requirements
in a cost efficient manner. The recommended NVIDIA stack-ups achieve these requirements w ith efficient use of board layers.
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NVIDIA Jetson TX2/TX2i OEM Product Design Guide
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