[NTLK] How thick is the ROM board?

[DXH]

Hey Matthias,
Glad to hear you got your ROM board sorted out. Soldering the flash chips is tedious but doable (with patience). I have to agree that it is a lot better to let a fab house do it.

CPLD’s from Lattice, Altera, Xilinx etc. are pretty much obsolete now. You can still get them however. I just bought some Xilinx XC9536XL for a couple of bucks a piece from a major distributor here in US. If you need more I/O bigger chips are available.

PCBman

Sent from my iPad

> On Feb 7, 2022, at 11:51 AM, Matthias Melcher <m.melcher at robowerk.de> wrote:
> 
> 
> 
>> On 6. Feb 2022, at 18:48, DXH <dxh at woh.rr.com> wrote:
>> 
>> The PCB thickness is determined by a number of parameters such as #layers, Cu thickness etc.
>> There are a range of thicknesses that can be fabricated, but, for practical and historical reasons, fab houses use a standardized set of sizes. These are usually 0.8, 1.0, 1.2 & 1.6mm for a four layer board.
>> 
>> The ROM board is 1.0mm.
>> 
>> The SIMM socket will actually support up to 1.27mm. The cam-in action will take up a small range of thicknesses.
>> 
>> PCBman
>> 
>>>> On Feb 6, 2022, at 10:53 AM, Sylvain Pilet <sylvain at pilet.net> wrote:
>>> 
>>>> Le 6 févr. 2022 à 16:46, Daniel Padilla <daniel.padilla at gmail.com> a écrit :
>>>> 
>>>> I'm getting 1mm thickness with my digital caliper  (that is calibrated).
> 
> Thanks guys. The corrected values reached me just in time and I was able to cancel my JLCPCB order. 1mm is great because JLC offers complete assembly of boards starting at 1mm. So, whee, no Flash RAM soldering for me. Let the Pros solder the board for me. Fingers crossed that my layout is correct.
> 
> On a side node, we were talking about CPLDs for the modem board. I am sorry to say that my original suggested chips seems to be no longer available. Actually, thanks to the current chip crisis, I can;t find any CPLDs that fit my needs and that the manufacturer would solder onto the board for me. So keep our fingers crossed that I winged my PCB layout correctly, and a programmable ROM board will be manufactured.
> 
> - Matthias
> 
> 
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