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Old 20th January 2006, 06:18 PM   #1
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Location: Seattle USA
Question max9709

Anybody play with these yet?

Or should this post be in Chip Amps?

BTW - it does list a high PSRR
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Old 20th January 2006, 07:05 PM   #2
BWRX is offline BWRX  United States
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It looks like it would be an interesting chip to work with (I don't like the TQFP package it comes in though).

It lists a high PSRR but that's only at 1kHz where that figure just so happens to be at its best (marketing strategy...). At 20kHz the PSRR is closer to -50dB instead of the -90dB at 1kHz. I also hate how everyone markets their stuff as 25/50W when that's at 10% THD+N...

It can be used without an output filter but it would radiate a lot of HF garbage, so it would be best to use a filter if you planned to make an amp based on this chip.

You can peruse spec sheets all day but that won't help you figure out how the thing will actually sound. If you're feeling adventurous take a stab at building one. That's what I'm doing, just with something else
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Old 5th July 2006, 07:04 AM   #3
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I have a couple of these with me.
Has anyone used this ic i.e implemented it as an amplifier before?
can someone design the pcb for this ic based on the application circuit in the datasheet pdf( .there is a evaluation kit also for this out here>>
the package that i have is THIN QFN, 56 lead.

Never Underestimate The Bandwidth of A Station Wagon Full Of Magnetic Tapes Hurtling Down The Highway...................Andrew S Tanenbaum
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Old 20th December 2010, 07:52 PM   #4
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How good is the max9709?

Im working on the pcb design.

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File Type: png macsche.png (166.3 KB, 1023 views)

Last edited by electroconico; 20th December 2010 at 07:59 PM.
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Old 21st December 2011, 06:46 AM   #5
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hi sir
please tell me the availability of max 9709 in india
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Old 17th May 2012, 02:01 PM   #6
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Originally Posted by electroconico View Post
How good is the max9709?

Im working on the pcb design.

Hi sir,
can u provide me the schematics for your design, and can u just tell me how is the MAX9709 working, is it reliable as i'm about to design an amplifier out of those, so please provide me the data.

Thank you
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Old 7th August 2012, 02:57 PM   #7
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i build myself a 9709 monostage in 1-layer-design. So far temperature is not a problem, but i havent tried a 100%-run on 22V.

Powered by 12V PSU the IC topside will be at ~42C after 10 minutes of 1kHz square wave input near clipping, so at 12V supply voltage, no additional heatsinking is required.

Strangely the IC is only pulling some 800mA from the PSU at this, so i gues impedance of the speaker is not as low as 4ohms.

Layout is working as is and it is considered to place a heatsink on the bottom side of the pcb.

Working params are:
SSM 200kHz +/-4
Mono bridged (1x50W)
22V max input
36dB gain
120C temp shutdown via /mute input
filterless output

Cheers doc
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File Type: jpg max9709_fin1.jpg (29.9 KB, 854 views)
File Type: png max9709_shematic.png (35.3 KB, 851 views)
File Type: png max9709_pcb_top.png (36.5 KB, 271 views)

Last edited by doctormord; 7th August 2012 at 03:00 PM.
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Old 8th August 2012, 09:23 PM   #8
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There it is.
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Old 9th August 2012, 12:02 AM   #9
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It looks great!
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Old 28th August 2012, 11:57 PM   #10
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Doctormord do u mind share ur .brd archive? or the pdf whit the pcb rdy to print?

I want build this amp for my pc speakers.
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