Hi,
i have created a draft for an input selector that should switch 4 Toslink and 1 Spdif input to one output at cmos level. The switching itself should be done by HC151N. Dout is going to a Teensy4.0 SPDIF_in, the IC will be controlled by that Teensy via the IO-lines. I would like to ask for your support to find some mistakes or improvements, because. This is only my second pcb design and I am not experienced in this.
From my point of view, it would be better to decouple the Spdif_in by transformer, but which one to choose and how to connect? Should i pull down the IO-lines? Anything other to criticize?
i have created a draft for an input selector that should switch 4 Toslink and 1 Spdif input to one output at cmos level. The switching itself should be done by HC151N. Dout is going to a Teensy4.0 SPDIF_in, the IC will be controlled by that Teensy via the IO-lines. I would like to ask for your support to find some mistakes or improvements, because. This is only my second pcb design and I am not experienced in this.
From my point of view, it would be better to decouple the Spdif_in by transformer, but which one to choose and how to connect? Should i pull down the IO-lines? Anything other to criticize?
Many SPDIF receiver ICs have multiple inputs. WM8805, CS8416 etc. Not familiar with Teensy so possibly an out of context post.
The Teensy has a async spdif_in with resampling function in the standard audio lib, i would like to use. So the task ist to route the selected input to output. IMO the receiver ICs are a little bit overkill for usage as a simple router. In addition, i don't have experience to handle such complex ICs also to solder SMD. This makes me little bit "scared"🤔. There is an SMD component n the board, but if something goes wrong, i have burned some cents, instead of10+$.
Besides that, whats about to use a pulse transformer or something like that?
Besides that, whats about to use a pulse transformer or something like that?
I would go to a CBTLV3251 instead of the HC151. Same pinout and function but only in SMD available. These are simple fet switches, very wide band, minimal propagation delay and skew.
Thanks, thats what i was looking for.
If i am not wrong, the HC151 is also buffering the signal, the 3251 is just switching. From my point of view, the propagation delay doesn't matter as long as ON/OFF has the same. Please correct me. Maybe i will add booth ICs to the PCB, so i can do some experiments and check whats better. Thanks.
Should i add some series resistors in the data lines as termination R?
From what I used:
Pulse H2260 and E2023 for 2 coaxial inputs.
Murata DA101C.
Works very good!
Alex.
Pulse H2260 and E2023 for 2 coaxial inputs.
Murata DA101C.
Works very good!
Alex.
Yes, the HC would also buffer the signal. But how long are your traces going to be? If you are staying on the same pcb, not going with a cable to another pcb then you really don't need a buffer. That 3251 is more like a relay, that is why I like it.
Also (more) important is if you are confident with SMD.
Also (more) important is if you are confident with SMD.
Dear OP, the transformer is only meant for coaxial S/PDIF. TOSLINK doesn't need a transformer as it is optically coupled interface.
Besides, the TOSLINK receivers are TTL and can therefore be switched via digital MUX, as opposed to analogue switches. As you've correctly guessed, the MUX is also a repeater that buffers the TOSLINK rx which has hardly any drive capability.
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Thanks for all inputs.
I would like to prefer the Murata DA101C for the coaxial input, but it is not easy to buy here. If i am not able to get it, would switch to the Pulse transformers.
The Signal is going to an other board (that has to be created), where the Teensy is mounted. --> HC151N Nevertheless thanks Havoc.
It is planned to use VCC of 3.3V, because of the Teensy inputs. I had checked the H/L levels in datasheets of the TOSLINK receiver and HC151, it should work. It is LV-TTL😉.
I will try to get some DAC101C, the other main parts like the TOSLINK receivers and ST485 are just ordered. Meanwhile i will work on the pcb design and will give update. But always bring on your points.
I would like to prefer the Murata DA101C for the coaxial input, but it is not easy to buy here. If i am not able to get it, would switch to the Pulse transformers.
The Signal is going to an other board (that has to be created), where the Teensy is mounted. --> HC151N Nevertheless thanks Havoc.
It is planned to use VCC of 3.3V, because of the Teensy inputs. I had checked the H/L levels in datasheets of the TOSLINK receiver and HC151, it should work. It is LV-TTL😉.
I will try to get some DAC101C, the other main parts like the TOSLINK receivers and ST485 are just ordered. Meanwhile i will work on the pcb design and will give update. But always bring on your points.
DA101C @Mouser - $1.6
DA101MC, DA101JC @Digikey - $1.12 (if you are afraid of SMD, you can bent it's legs and get TH 🙂).
Alex.
Mouser and Digikey shipping cost is about 20€ from US to DE without TAX.
I have found it on tme.eu for 2.98€.
I have found it on tme.eu for 2.98€.
Only for parts from EU stock, i had added a LCD display for 69€. Shipping for LCD zero, for DA101C 20€, because of shipping from US. But doesn't matter anymore, i had ordered from tme.
Maybe you want not only this component but others.
To me after $100 shipping is free from DK/Mouser, just VAT and custom.
TME is OK, if the shipping to you is cheap (to me shipping from TME is expensive).
Also Farnell have DA101 for 1-1.5 euro. As I remember, free shipping limit was ~60-70 euro.
Alex.