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Practical Circuit for RS422 and RS485
2 years 8 months ago #292172
by blazini36
Replied by blazini36 on topic Practical Circuit for RS422 and RS485
I never noticed that. Honestly I can't remember why I started using that driver, probably price and availability. I looked at some of the other ~$2 quad drivers that I can buy in a wide 16-SOIC and they all look like they 1/2 swing. I've tested step drivers upto 2krpm @ 16x and never seen an issue, though a full swing chip would obviously be better.
The ISL32174 has the same pinout but it's only available in a narrow 16 or QFN. Re-routing will be easy and not a huge deal since I only ever run a handful of PCBs anyway. I'll definitely be switching to this
The ISL32174 has the same pinout but it's only available in a narrow 16 or QFN. Re-routing will be easy and not a huge deal since I only ever run a handful of PCBs anyway. I'll definitely be switching to this
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2 years 8 months ago #292173
by PCW
Replied by PCW on topic Practical Circuit for RS422 and RS485
Note that the ISL32174 in the narrow SOIC has been discontinued
so suggest ISL32172 if you want that package.
Note that if you are not using the tri-state feature, you can tie
both enables high and then you can use 172/174 parts
interchangeably
so suggest ISL32172 if you want that package.
Note that if you are not using the tri-state feature, you can tie
both enables high and then you can use 172/174 parts
interchangeably
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2 years 8 months ago #292178
by blazini36
Replied by blazini36 on topic Practical Circuit for RS422 and RS485
Yeah, I don't use tri-state for those. Looks like the IS chips are quite a bit faster too, ~15ns between input state change to output switch. The SN75174's probably closer to 100ns, according to the datasheets
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2 years 8 months ago #292627
by blazini36
Replied by blazini36 on topic Practical Circuit for RS422 and RS485
PCW, got another question for ya.
I have a servo drive that uses TTL UART. Wasn't originally planning on using it with this but now I am lol. If I set that differential transceiver up for full duplex and no termination, I should be able to just use TX+ and RX+ to RX and TX of the servo drive as long as the grounds are tied together right?
I did actually make an isolated RS422 adapter for the drive years ago but I think there was a problem with the PCB and I don't remember revising it.
I have a servo drive that uses TTL UART. Wasn't originally planning on using it with this but now I am lol. If I set that differential transceiver up for full duplex and no termination, I should be able to just use TX+ and RX+ to RX and TX of the servo drive as long as the grounds are tied together right?
I did actually make an isolated RS422 adapter for the drive years ago but I think there was a problem with the PCB and I don't remember revising it.
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