LME 49811 Project?

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that sch has a 5pair output stage.
That can be used to determine the maximum output power.
then you progress via the speaker impedance to your required supply rail voltage to meet your targets.

A 5pair output stage takes a lot of driving. It has 5times as much base current and has 5times as much capacitance. This load has to be driven by the driver stage.
That is probably why the sch shows two drivers in parallel.
You as the re-Designer should carry out a temperature de-rated SOAR on the outputs and on the drivers.

The output inductor needs a damping resistor.
The decoupling on the supply rails may need to be distributed along and between all the drivers and outputs. At worst you may need MF and HF decoupling at every device collector. That would add up to 28 decoupling capacitors. I suspect you could get away with 6 HF caps and 4 MF caps, rather than the 4 shown.

I suspect from the question that all of the above is beyond your current capabilities. Find a well recommended kit that has a full build guide.
The PCB layout and Project 16 BOM are provided for free, as is, no warranty.
Do you remember reading this in your link?
 
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that sch has a 5pair output stage.
That can be used to determine the maximum output power.
then you progress via the speaker impedance to your required supply rail voltage to meet your targets.

A 5pair output stage takes a lot of driving. It has 5times as much base current and has 5times as much capacitance. This load has to be driven by the driver stage.
That is probably why the sch shows two drivers in parallel.
You as the re-Designer should carry out a temperature de-rated SOAR on the outputs and on the drivers.

The output inductor needs a damping resistor.
The decoupling on the supply rails may need to be distributed along and between all the drivers and outputs. At worst you may need MF and HF decoupling at every device collector. That would add up to 28 decoupling capacitors. I suspect you could get away with 6 HF caps and 4 MF caps, rather than the 4 shown.

I suspect from the question that all of the above is beyond your current capabilities. Find a well recommended kit that has a full build guide.Do you remember reading this in your link?

Yeah i know,thanks Andrew for help.All of output transistor will have own 100uf deoupling and drivers will have 220uf,lm 220uf also.Two layer board with top side reserved for decoupling ground plane.
 
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Taken from the PDF i posted: -

SUPPLY BYPASSING
The LME49811 has excellent power supply rejection and does not require a regulated supply.
However, to eliminate possible oscillations all op amps and power op amps should have their supply leads bypassed with lowinductance capacitors having short leads and located close to the package terminals.
Inadequate power supply bypassing will manifest itself by a low frequency oscillation known as “motorboating” or by high frequency instabilities.
These instabilities can be eliminated through multiple bypassing utilizing a large electrolytic capacitor (10μF or larger) which is used to absorb low frequency variations and a small ceramic capacitor (0.1μF) to prevent any high frequency feedback through the power supply lines.
If adequate bypassing is not provided the current in the supply leads which is a rectified component of the load current may be fed back into internal circuitry.
This signal causes low distortion at high frequencies requiring that the supplies be bypassed at the package terminals with an electrolytic capacitor of 470μF or more.
 
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This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.