Re: [beagleboard] Re: Burned out BBB with AIN0 > 1.8V

Thanks, Harvey, that's an awesome explanation! > So firstly, let's feed all the sensors from 1.8 volts. Now this > works, and can work well. The question is how to get the 1.8 volts. A > switching converter, while efficient, generates noise, is relatively > complex, and is moderately

[beagleboard] Re: Burned out BBB with AIN0 > 1.8V

Doyle S wrote: > > Any suggestions or part numbers are much appreciated! Please, if it's not > to difficult, let me know which op-amps you've used. > After a little looking I found it. I'm using LM10CN op-amps. > I've worked with the LM324 in the past for another project

[beagleboard] Re: Burned out BBB with AIN0 > 1.8V

el huitzilo wrote: > [-- multipart/alternative, encoding 7bit, 89 lines --] > > [-- text/plain, encoding 7bit, charset: UTF-8, 35 lines --] > > Hi, > > chiming in here because I'm about to build my first circuit that uses ADCs > on BBB... > > > My standard advice >

Re: [beagleboard] Re: Burned out BBB with AIN0 > 1.8V

On Tue, 7 Jun 2016 15:20:30 -0700, you wrote: >Good explanation. The other benefit from using an opamp is the low impedance >it provides to the ADC Sample circuit. As you know, when the circuit is >in sample mode, it is charging and internal capacitance which means the >current spikes for a

Re: [beagleboard] Re: Burned out BBB with AIN0 > 1.8V

On Tue, 7 Jun 2016 09:43:50 -0700 (PDT), you wrote: >Any suggestions or part numbers are much appreciated! Please, if it's not >to difficult, let me know which op-amps you've used. MCP604SL, and there are 1 and 2 amp versions of that chip. It's currently protecting an XMEGA (3.3 volt VCC here

Re: [beagleboard] Re: Burned out BBB with AIN0 > 1.8V

On Tue, 7 Jun 2016 13:03:29 -0700 (PDT), you wrote: >Hi, > >chiming in here because I'm about to build my first circuit that uses ADCs >on BBB... > >> My standard advice >>> > would be to run the analog voltage through a non-inverting op amp >>> > configured as a gain stage. You run the

Re: [beagleboard] Re: Burned out BBB with AIN0 > 1.8V

> What you're talking about does not make any sense. an ADC measures > voltage. ADC's do not have sensors connected to them. > Sorry, I probably have not phrased my use-case clearly enough... I'm connecting sensors to the ADCs. These sensors change their resistance when sensing something.

Re: [beagleboard] Re: Burned out BBB with AIN0 > 1.8V

> > *It's generally thought of as an amateurish / incomplete way of "dividing" > voltage. But it can work in a pinch . . .* Well I meant by its self. It's my understanding that an auto ranging circuit is roughly a resistor network( divider ) in conjunction with other parts, in order to achieve a

Re: [beagleboard] Re: Burned out BBB with AIN0 > 1.8V

> > > > > *In my somewhat amateurish approach to this I was planning to use a DC-DC > converter to provide 1.8 VCC for my sensors. I'm still learning about > op-amps and anything more advanced than a transistor, so I wonder whether > there are any advantages to using an op-amp compared to

[beagleboard] Re: Burned out BBB with AIN0 > 1.8V

Hi, chiming in here because I'm about to build my first circuit that uses ADCs on BBB... > My standard advice >> > would be to run the analog voltage through a non-inverting op amp >> > configured as a gain stage. You run the op-amp (and have to pick one >> > that does rail to rail and

[beagleboard] Re: Burned out BBB with AIN0 > 1.8V

Harvey White wrote: > >3. What is the "normal" way of using the BBB analog inputs with 5V levels? > > Is it possible - or is there where I would use a level-shifter or zener > >diode? > > Level shifters are generally digital, and zener diodes don't help all > that much

Re: [beagleboard] Re: Burned out BBB with AIN0 > 1.8V

No, you most likely killed the DDR as well. 1.8V powers most of the I/O rails internal to the processor. So as you hit those pins which such high voltage, I would expect it to hit the DDR and maybe even the the Ethernet PHY. There is also a good chance the I/O rail bled over into the 3.3V rails,

Re: [beagleboard] Re: Burned out BBB with AIN0 > 1.8V

> > > *Gerald - Assuming I just killed the AM335, would most of the other > components on the board be okay, aside from possibly the Power Management > chip?* I cant tell you what Gerald can most definitely he knows the hardware better than I. However I can tell you if you have another board of

[beagleboard] Re: Burned out BBB with AIN0 > 1.8V

Thanks all! No doubt it was my fault - I'm not trying to blame anyone else, I was more curious about what I did to my board. =) I had a couple other BBB's around so I was a bit cavalier with the whole thing - lesson learned, haha. I really appreciate all the info, and will check all the