Thanks for the comments everyone, a project video on this topic will be coming up soon, and I'll post the Altium design files for that project once we release the video.

@myetis1990

Жыл бұрын

Hey, Zach great content as ever ! You are the king at teaching theory about all HW. I would love to see a numeric example for an input analog channel pin impedance design for the stability of the sampling.

I’d love to see a video on audio A/D’s & preamps which have to measure microvolt signals from really low level sources at essentially DC. Specifically hum isolation and the fact that at low frequencies, the return currents are diffuse. I.e. digitizing a 1 V rms signal with 100 dB of dynamic range, without hum.

Gracias tio Zach, saca muy buenos consejos. Saludos!

Very clear and concise. Gj

Hi Zack, can you make a video on BUCK-BOOST converters, it's confusing for me to find a chip that do that (confused with buck chips in digikey results...)

good vidéo i like

Love this video. I still use a low pass filter to isolate noise propagate from DPWR to APWR but if I tie Vref to APWR. Would it fine? i worry some pules generate when adc in accquition phase because they fast charge internal sampling caps and it will pollute my Vref rail. Another question is if I use opamp would the power pin of opamp be connected to APWR or DPWR ?

@Zachariah-Peterson

6 ай бұрын

Thank you, You can use a dedicated supply for VREF. An LDO for APWR is an option but you have to worry about the inaccuracy in your output divider network (if present) and in temperature drift, this is why you might place a precision reference between the LDO and the VREF pin. When using DPWR, you just need to make sure the rail is properly filtered. I sometimes see ferrites used for this, which might be okay only because VREF draws DC power, I would recommend to test on your board and if the ferrite creates too much noise you can swap it for a resistor instead. About the op-amp, if the op-amp is not supplying fast pulses (square waves) then it will probably be fine to use it on either rail, just include one additional capacitor near the input pin for decoupling.

Great content! Deserves more exposure

@AltiumAcademy

Жыл бұрын

Glad you think so!

Thankyou very much for the great explanation and good video. Would it be also possible, when using a single supply for VD and VA to put a ferrite bead for the isolation, or is it better to place the resistor R6 with 51 ohms? Kind regards

@Zachariah-Peterson

Жыл бұрын

I don't want to generalize that the resistance should be 51 ohms. The value you should use depends on the other components that are connected to the VD net and how fast the analog supply needs to pull power during the acquisition period. 51 Ohms is small enough to not limit that particular ADC during its acquisition and sampling period. In any case, I would not recommend a ferrite unless you can prove that the ferrite will work, such as in a test board. If you had a test board with a ferrite, and you are seeing excessive noise on the digital readout, but the digital rail power is mostly clean, then you might be boosting noise into the analog rail with the ferrite's inductance and it is probably interfering with the sampling circuitry.

@heinerwilmsmeyer9262

Жыл бұрын

@@Zachariah-Peterson Thankkyou very much for the answer : )

Could you add the analog input filter calculation for the next video if possible? I would like to know for example the frequencies that the low pass filter will remove and how that can affect the measurements. Thank you for your time.

@Zachariah-Peterson

Жыл бұрын

Here you go: kzread.info/dash/bejne/Z4eB1bR6oNbYgbQ.html

Great work!

@AltiumAcademy

Жыл бұрын

Thanks for the visit

Excellent info.

@AltiumAcademy

Жыл бұрын

Glad you think so!

Nice!

Great content as always. Please go easy on the zoom cuts as it can be very distracting as a viewer.

❤❤

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