Tuesday, March 3, 2009

AMS - Magnetic Encoder

AustriaMicrosystems: encoders, power, op amps and supervisory circuits: "
I wrote up a piece about AustriaMicrosystems’ 12 bit hall-effect rotary encoder and the ebullient and cheerful Mary Bohenek was nice enough t...
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This thing is a blast—imagine having 12 bits of absolute rotary position available the movement you turn the part on. No boot up— it just starts working. Now I did see the pointer slap to zero a few times as I was playing around and I have to believe that was because I was running the magnet way too close. I am sure the part was OK; after all, anything that goes bad is most likely Windows doing something bad. The numbers on the board itself never slapped to zero, just the pointer on the little windows app you can load if you want. The part puts 6 Hall sensors into the chip so it can not only tell rotation, it can tell tilt, and just as cool—by looking and the AGC status you can tell how close the magnet is to the chip. This means you could monitor a joystick with a pushbutton and rotary sleeve with this one part. I remember asking them what the part cost and it was something ridiculously cheap like 6 or 7 bucks.

How they get 6 hall sensors, a 12 bit A to D and all the status and control circuitry into this thing for so little, well you have you love those Austrians. They have all the engineering perfection of the Germans without that need to invade neighboring countries. As a person of Croatian decent, I have to love Austria because Croatia was once part of the Austrian empire. What has really caught my eye is the broad selection of stuff AustriaMicrosystems does in the analog world.

They just sent a press release about a single alkaline cell synchronous boost converter. The AS1323 will start up at 0.95 volts, which is a big deal, and boost that voltage to 2.7, 3 or 3.3 volts depending on the part you use. Cooler yet, once it has the 0.95 volts to startup on, it will work all the way down to 0.75 volts. This is really good stuff. The part puts out 100mA and comes in a TSOT. It has 1.6 uA of quiescent current and draws 600 nA in shutdown. The part costs $1.38 in 1000s.

After that they sent a release about a low voltage supervisory circuit, like the ones Maxim and other companies make. It is meant to monitor supply rails between 0.9 and 1.5 volts. They can trim the reset voltage at the factory for anywhere from 0.81 to 1.425 volts and give a 5 or 10% tolerance. The AS1925 has one active high and one active low reset; the AS1926 has a push-pull active high and an open drain active low output. Cost is $0.24 in 1000s.

Ten what really blew me away was a press release about an AustriaMicrosystems op amp. As a former amplifier applications engineer at National Semi I thought I knew all the amplifier manufacturers, even lesser known ones like Cirrus Logic, that makes instrument quality chopper amps. Now I see AustriaMicrosystems makes a nice 10MHz, 10V/uS rail-to-rail op amp. The AS1710 runs off 2.7 to 5.5 volts. It will sink or source and impressive 50 mA of current. It does draw 1.6mA of quiescent but that gives it speed and low noise (10nV/rtHz). It comes in a 6 pin SC70. Cost is $0.18 in 1000s

Well way to go AustriaMicrosystems, four great parts and nothing but net. Keep up the good work and if one of you readers wants my AS5046 demo board, drop me a line and I will send it to you. We mind as well keep this cool board in circulation. You will have to go to AustriaMicrosystems web site and download the driver but that in no big deal, 30 seconds max.

www.AustriaMicrosystems.com

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