Another MAX9926 VR board

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Fred
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Re: Another MAX9926 VR board

Post by Fred »

Yeah,but not for the purpose of dedicated VR use.
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russian
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Re: Another MAX9926 VR board

Post by russian »

I am far from understanding anything electrical, but I believe a common approach is to use 5k+5k instead of one 10K. I believe it was mentioned that this is a recommendation from some MAX application note.
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Re: Another MAX9926 VR board

Post by Fred »

They mention series/parallel resistor combos in an app note? Really? Max supplying elementary passive component selection advice to professional engineers in an app note. Risky business. Even I would feel patronised by that... Got a reference?
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Re: Another MAX9926 VR board

Post by Ethan »

You are likely thinking of their evaluation board schematic, which uses two 5k in series instead of 1 10k. Can't remember the reason now, but it may have been to make the LPF more configurable.


Just had a look, they are only there to share the current, so they can use lower wattage resistors.

http://datasheets.maximintegrated.com/e ... UEVKIT.pdf
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Re: Another MAX9926 VR board

Post by ivan141 »

I dusted the cobwebs off of this PCB design last weekend, with Fred's recommended (optional) shunt resistor sized to accept regular through-hole 2W fare.
The first batch of 10 PCB's will be put in production this week somewhere in China (using Elecrow again, like their service a lot).
I'll post some more info once I receive the PCB's, I can assemble about 5 with the sample 9926's I have.
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Re: Another MAX9926 VR board

Post by KLAS »

depending on price, i would take one or two assembled units. maybe even some bare PCB
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Re: Another MAX9926 VR board

Post by ivan141 »

I'd wait a little if I where you. Just found out it was unwise to be so hasty with sending off the gerbers..
Had this nagging feeling and rechecked the design, shunt is in the wrong place. No big loss but it'll take
a little longer to get the corrected design fabbed.
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Fred
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Re: Another MAX9926 VR board

Post by Fred »

Image

Gutted! :-(
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Re: Another MAX9926 VR board

Post by ivan141 »

'Tis but a scratch... I've mailed them a request to update the gerbers if it hasnt hit production yet (fat chance), or to just pay another 10 dollars and have them
ship the corrected pcb along with the duds.
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Re: Another MAX9926 VR board

Post by Fred »

FWIW the shunt can be installed in the loom right at the connection to the board or box or whatever. It doesn't have to have PCB real estate, it's just cleaner for it to, and rules out putting it too far away and allowing a noise injection window between it and the board.
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