Quick question – I'm using a RS485 transceiver for transmit only, and for a SIOC8 part there are two commonly used I've seen on the internets:
MAX485 @ (£)1.83
& SN75176BD @ 0.271
and there's ADM4852ARZ @1.67
(lowest qtys to compare)
Most specs seem to compare, but i don't see any transmission rate info for the Texas part…
But even so – why such a massive PPU difference? Is there any advantage in the more expensive parts for the 250kbps data rate DMX runs at?
Power is not an issue. I'm going for the cheap part!
SN75176BD it is!
Best Answer
The 75176 is an old TI bipolar part that uses a lot more more power (especially quiescent power). It's perhaps more rugged than the MAX485 CMOS parts (ymmv) so if you have plenty of power it might be preferable. It also works a lot faster than the MAx485 (10 vs. 2.5 MBPS) but either is ok for DMX512. If you're running continuously into a terminated line (as you typically would with DMX) you may not notice the power difference that much.
The slew-rate limiting on the ADM4852ARZ might make it more tolerant to dubious terminations and would reduce EMI.