Maximum Voltage for Stereo 20W Class D Audio Amplifier - MAX

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westyd1982
 
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Maximum Voltage for Stereo 20W Class D Audio Amplifier - MAX

Post by westyd1982 »

Stereo 20W Class D Audio Amplifier - MAX9744
PRODUCT ID: 1752

Since there has been no answer, I will try asking my question again in its own thread. Will 15v max damage this amplifier?

I want to power this amplifier from a 12v solar-charged battery bank (660amp-hours - off-grid). The solar charge controller can raise battery bank voltage as high as 15v max when it is equalizing the batteries or when the batteries are very cold. The battery voltage is raised to about 14.5v on a typical day. At night the battery bank typically runs around 12.4v.

If so, would putting a power diode or two on the power input lower the voltage sufficiently? Something like a 1N4001 or 1N4004? The lowest the voltage gets is 11.5v.

Agent_24
 
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Re: Maximum Voltage for Stereo 20W Class D Audio Amplifier -

Post by Agent_24 »

The datasheet for the MAX9744 says maximum voltage 14v so yeah, you'll probably have a problem with 15v.

Diodes would work but depending on how much current that amplifier draws, you may need pretty big diodes with heatsinks.

A low dropout 12v regulator or buck converter might be a better idea, .

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westyd1982
 
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Re: Maximum Voltage for Stereo 20W Class D Audio Amplifier -

Post by westyd1982 »

Thanks. I read the data sheet also, and in the ABSOLUTE MAXIMUM RATINGS section it says:

PVDD to PGND ....................................................................+16V

It also says:

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Figure 10 on page 22 shows a supply voltage of 4.5-14.5v.

I was hoping someone from Adafruit can verify that the other components on the board can work up to 15v. This is the maximum voltage of my battery system and it looks like the MAX9744 chip should be able to handle it.

I plan on using this amplifier with a Raspberry Pi, two Bose 501 outdoor speakers, and shairport software to create an outdoor "wireless" speaker system.

Agent_24
 
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Re: Maximum Voltage for Stereo 20W Class D Audio Amplifier -

Post by Agent_24 »

westyd1982 wrote:Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
^^ That's the important part. It should not blow up immediately running at maximum or near maximum rating but you may well get problems sooner rather than later.

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adafruit_support_bill
 
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Re: Maximum Voltage for Stereo 20W Class D Audio Amplifier -

Post by adafruit_support_bill »

Absolute Maximum ratings are conditions above which damage is almost certain. Prolonged operation at or near these limits is likely to result in premature failure of the device.

We do not recommend operating this at more than 14v.

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lejaybo
 
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Re: Maximum Voltage for Stereo 20W Class D Audio Amplifier -

Post by lejaybo »

hi

is there a 12v regulator you can recommend?

i was thinking of retro fitting one into an old car radio


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lejaybo
 
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Re: Maximum Voltage for Stereo 20W Class D Audio Amplifier -

Post by lejaybo »

awesome

cheers Bill

Agent_24
 
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Re: Maximum Voltage for Stereo 20W Class D Audio Amplifier -

Post by Agent_24 »

Don't forget to give it a heatsink :)

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