.125W resistors should be fine.
There are a number of different 1117 regulator models. Some are available in different footprints. Probably any of them will work for this so long as the output voltage and the footprint are correct. Other than that, one can compare data sheets to look for any possible issues. Not sure if anyone actually knows that a particular brand of 1117 regulator won't work for this project.
Also, the Consumer temperature range FPGA is often out of stock; however the Industrial version works fine too. The former has a C in the part number whereas the latter has an I.
There are a number of different 1117 regulator models. Some are available in different footprints. Probably any of them will work for this so long as the output voltage and the footprint are correct. Other than that, one can compare data sheets to look for any possible issues. Not sure if anyone actually knows that a particular brand of 1117 regulator won't work for this project.
Also, the Consumer temperature range FPGA is often out of stock; however the Industrial version works fine too. The former has a C in the part number whereas the latter has an I.
Hi all,
I am about to order some v2 PCBs from JLCPCB but cannot really make any of the readily available PCB options (thickness of PCB & Prepregs) fit with a 50 ohm trace impedance.
In KiCAD's Gerber viewer I measure the traces on the PCB to be 0.254 mm but for a 50 ohm impedance that doesn't appear to fit well with the available 0.8-1.2 mm options from JLCPCB ...
Anyone knows what the specifications for the PCB is in terms of thickness, prepreg thickness, copper thickness, etc. ? I have made a search of the thread with Google but without any result ...
BTW should anyone be interested there will be 2 PCBs for free, i.e. you pay shipping costs from Denmark to you - typically EUR 7-10.
Cheers & thanks, Jesper
I am about to order some v2 PCBs from JLCPCB but cannot really make any of the readily available PCB options (thickness of PCB & Prepregs) fit with a 50 ohm trace impedance.
In KiCAD's Gerber viewer I measure the traces on the PCB to be 0.254 mm but for a 50 ohm impedance that doesn't appear to fit well with the available 0.8-1.2 mm options from JLCPCB ...
Anyone knows what the specifications for the PCB is in terms of thickness, prepreg thickness, copper thickness, etc. ? I have made a search of the thread with Google but without any result ...
BTW should anyone be interested there will be 2 PCBs for free, i.e. you pay shipping costs from Denmark to you - typically EUR 7-10.
Cheers & thanks, Jesper
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AFAIK in JLCPCB 4-layer boards only the core thickness varies so the insulation between layers 1 & 2 and 3 & 4 has same thickness regardless of total PCB thickness. So the correct trace width for 50ohms would be about 0.4mm but difficult to say if 64ohms from 0.254mm trace matters much in this device.
@bohrok2610: Thanks for your feedback ... I reckon you are right when it comes to the traces within the PCB itself. My consideration was the, well, relatively unlikely situation where I (or somebody else?) might be using the u.fl. connections with somewhat longer u.fl. cables .. Anyway, in case this proves relevant at some point in time it should be possible to adjust the termination resistors accordingly. So I will just go with a 1mm standard PCB.
Cheers, Jesper
Cheers, Jesper
@gentlevoice ,
I don't know if that helps : in the Kiclad tools you have an impedance calculator (WG gnd included) where you could find the distance needed of the inner gnd layer by specifing the length (so one or to inch in such a pcb) and the width of the traces.
I have pronted with them traces as low as 0.19 mm and 6 mils ground distance for illustration but never have used their impedance tools.
By default the outside layer are 1 oz and 1/2 for the inner layers, which you can specify for the impedance comput in the Kicad impedance tool as well. Of course you only need this if you can rewoek in Kickad the distance of the coplanars WG grounds and inner ground layer distance.
Not sure I understand if you can do thta with the gerbers you use from third party soft ?!
I don't know if that helps : in the Kiclad tools you have an impedance calculator (WG gnd included) where you could find the distance needed of the inner gnd layer by specifing the length (so one or to inch in such a pcb) and the width of the traces.
I have pronted with them traces as low as 0.19 mm and 6 mils ground distance for illustration but never have used their impedance tools.
By default the outside layer are 1 oz and 1/2 for the inner layers, which you can specify for the impedance comput in the Kicad impedance tool as well. Of course you only need this if you can rewoek in Kickad the distance of the coplanars WG grounds and inner ground layer distance.
Not sure I understand if you can do thta with the gerbers you use from third party soft ?!
@diyiggy : Hi ... & thanks for your suggestions. As it is I normally use Saturn's PCB Toolkit which a.o.t.s also have an impedance calculator that considers plane distances, relative permittivity, and trace width. However, in practice I have chosen to comply with the trace width suggested by JLCPCB (their "impedance calculator"), as it differs slightly from the values suggested by Saturn, and I reckon/hope that JLCPCB know better what would be the correct values with the PCBs they use.
And regarding modifying the Gerbers for the PCM2DSD PCB I do not know of any way of doing this - so it will have to be best fit and then adjusting the termination resistors as well as is possible.
Cheers, Jesper
And regarding modifying the Gerbers for the PCM2DSD PCB I do not know of any way of doing this - so it will have to be best fit and then adjusting the termination resistors as well as is possible.
Cheers, Jesper
@bohrok2610 : I agree and will also be reclocking the DCLK from the FPGA output. My reason for considering this is, as I mentioned in the post above, the admittedly unlikely case that at some point in time I or somebody else might be using this board with longer u.fl. cables 
. But, anyway, thanks for pointing it out ... I have ordered the boards by now.
Cheers, Jesper
. But, anyway, thanks for pointing it out ... I have ordered the boards by now.Cheers, Jesper
@PJotr25 or anyone else that can help:
I was just putting together a Mouser order for a PCM2DSD and found that the M25P80 Flash memory chip is obsolete. Would the Renesas AT45DB081ESSHN-T https://www.mouser.co.uk/ProductDet...S-RX1dyy-nC_7Jing619Q9OV2QUG9CjLczVr65VeP1lSK be a viable alternative, or would you recommend something else?
Thanks
I was just putting together a Mouser order for a PCM2DSD and found that the M25P80 Flash memory chip is obsolete. Would the Renesas AT45DB081ESSHN-T https://www.mouser.co.uk/ProductDet...S-RX1dyy-nC_7Jing619Q9OV2QUG9CjLczVr65VeP1lSK be a viable alternative, or would you recommend something else?
Thanks
Here is what was posted about flash memory at some point:
info on sourcing flash memory from ebay:
MX25V8006EM1I-13G
M25P80-VMW6G FLASH MEMORY, 8MBIT STMicroelectronics
M25P80VMW6G SemiConductor - CASE: SO8 MAKE: NUM
They all program same as M25P80, as far as IMPACT is concerned.
There is a part from STMicroelectronics that can be used but its a tight fit because its a bit wider than the pads on the PCB. If the legs are folded under then it can still be soldered in place. Otherwise, new parts that fit the PCB pads are still available on ebay.
info on sourcing flash memory from ebay:
MX25V8006EM1I-13G
M25P80-VMW6G FLASH MEMORY, 8MBIT STMicroelectronics
M25P80VMW6G SemiConductor - CASE: SO8 MAKE: NUM
They all program same as M25P80, as far as IMPACT is concerned.
There is a part from STMicroelectronics that can be used but its a tight fit because its a bit wider than the pads on the PCB. If the legs are folded under then it can still be soldered in place. Otherwise, new parts that fit the PCB pads are still available on ebay.
Thanks guys, I found some M25P80 parts from a UK ebay supplier, although I am usually reluctant to buy semiconductors on there as I have been burnt a few times. Looking at the footprint, the standard SO8 should fit OK.
hi,Olek:
I also intrest your project,and wish you send me a copy of these code,thanks !my Email: hzwit@hotmail.com
Don’t waste money and efforts. Use Winbond W25x40. It works perfectly with ISE14.7.
Very easy to buy and cheap. Select the last item in the drop-down menu or M25p40, both are OK.
Very easy to buy and cheap. Select the last item in the drop-down menu or M25p40, both are OK.
Here is another board that only accepts I2S input and output. This may have the option to implement the board either before the FifoPiQ7 reclocker or after reclocking? Not sure. Is it preferable to have the PCM signal first reclocked via FifoPiQ7 and then the PCM2DSD board do its work?
https://www.ebay.com/itm/2263895362...ZrXenKbv1ncJ+DjNGUbyhpcHqZ|tkp:Bk9SR-jBkLO9ZQ
https://www.aliexpress.us/item/3256...2nPWbIlR&utparam-url=scene:search|query_from:
listed under:
https://geediy.com/
The above linked AK4137 boards are poor implementations of the AK4137 ASRC chip. The PCM2DSD converter of this thread is a synchronous converter, and far superior to the best implementations of AK4137 (I know, I could write all about it; please PM if interested in detailed discussion).
In addition, reclocking should be the very last step before going into the dac board. Both AK4137 and the FPGA-based PCM2DSD of this thread can benefit from having their outputs reclocked before going into the dac.
Regarding FIFO_Pi for reclocking, I would not necessarily assume it is the best or only solution. For one other example, there is my own open source design:
https://www.diyaudio.com/community/threads/general-purpose-dac-clock-board.413001/post-7729060 for a pic
https://www.diyaudio.com/community/threads/general-purpose-dac-clock-board.413001/post-7729422 for the open source files
In addition, reclocking should be the very last step before going into the dac board. Both AK4137 and the FPGA-based PCM2DSD of this thread can benefit from having their outputs reclocked before going into the dac.
Regarding FIFO_Pi for reclocking, I would not necessarily assume it is the best or only solution. For one other example, there is my own open source design:
https://www.diyaudio.com/community/threads/general-purpose-dac-clock-board.413001/post-7729060 for a pic
https://www.diyaudio.com/community/threads/general-purpose-dac-clock-board.413001/post-7729422 for the open source files
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