[Arm-netbook] HDMI High-Frequency Layout: Recommendations--Taper

[Richard Wilbur]

On Jan 5, 2018, at 23:49, Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:
> 
> On Sat, Jan 6, 2018 at 6:35 AM, Richard Wilbur <richard.wilbur at gmail.com> wrote:
>> So the trick is how to choose a faster chip and integrate successfully into a system running at lower speed than it is specified for?
> 
> yyup.  have to use the 1800mhz 1.5v x8 DDR3 IC, which fortunately
> happens to be down-compatible with 667mhz.  the 1.35v DDR3L variant of
> the same chip is *not*.

Your changes to the power supply capacitors and vias should help accommodate faster edges, etc. from the faster chips.

> still, i cannot risk just relying on one possible DDR3 IC, so i will
> have to source 1600mhz as well... and also last resort a 2gigabit IC
> which will total, qty 4, only 1GBYTE of RAM.
> 
> the budget's fixed... it's just the way it's going to have to be.
> make adjustments that fit within the budget, end of story.

Here's hoping the faster ones fit the budget and the circuit as I'm a big fan of providing as much RAM as possible!