fenn:
how do you know the electroswitch unit is based on the austria microsystems chip?
I had a phone call with an engineer at Electroswitch since their datasheet doesn't provide any information on the absolute version of their encoder. They refered me to the Austria Microsystems magnetic encoder ICs to get the information I needed.
I just want the chip on a board, not some big thing that pretends to be a potentiometer or optical encoder.
While not just a chip on a board, these are hardly large devices. Barely 1.75" long (including pins) and 0.6" wide, they are very small compared to equivalent devices and the hard part of keeping the magnetics aligned in a neat package has already been done. I'm not sure why you are looking at encoders but you don't want something that acts like an optical encoder. Sounds kind of self defeating to me.
using quadrature position output neglects the one big advantage of magnetic encoders, which is that you can ask the sensor “where are you?” whenever you feel like it and get back a precise answer, without having to constantly monitor quadrature signals and keep track of where it is.
There are absolute versions of the encoder available that have a fixed frequency output and a dutycycle that represents position. It is a trivial task to measure dutycycle if your MCU has capture hardware. There are also many MCUs that have hardware quadrature interfaces which makes interfacing with an incremental encoder very easy too.
supposedly the as5046 works up to 10,000 rpm, so you’d have to sample at 4MHz for equivalent speed and resolution with a quadrature interface. (however it won’t do both that speed and precision at the same time.)
Do you really need to know absolute position of a 10,000 rpm device? A hardware quadrature interface can easily handle an incremental encoder at that speed. If you don't have one, there is a Z-channel option which would allow you do keep track of full rotations until the connected device slows to a reasonable speed. The electroswitch parts are not designed for high speed systems (200 RPM max) mostly due to the bushing used.
the austria products also actually have datasheets, which are a plus.
Which is the reason I had to call electroswitch and ultimately introduced me to the Austrian Microsystems line of products.
-Bill