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# Regarding current consumption

Category: Hardware
Product Number: MAX98303

I am using max98303 audio amplifier for one of my project  at 5v supply.There will be load of 2 ohm on each output so total 4 ohm of load is at output side.So, my query is how much current it will take from 5V and  what will be the total current consumption.(it will be better if calculations is also shown).

• When you say that ‘there will be load of 2 ohm on each output so total 4 ohm of load is at output side’ do you mean that there the speakers (as shown in this diagram) are 2Ω?  Or do you mean something else?  Please provide a diagram to show the arrangements of loads if it is something other than the intended use case shown here.

Calculating the current consumption of the amplifier requires that you first find the power consumption of the amplifier.  Pconsumed = Vsupply * Iconsumed

The power consumption is based on the efficiency of the amplifier to deliver power to the load plus the base quiescent power draw of the amplifier.

Pconsumed = Pquiescent + Poutput/efficiency

From the datasheet:

So, Pquiescent = 5V * 2.7mA = 13.5mW

Peak efficiency in the datasheet is listed as:

This is the amplifiers’ ability to turn input power into output power which varies with load.  It is based on the resistor divider between the load and the output resistance.  Due to this relationship, we can also use this to get a close approximation of the output resistance of the amplifier (RON) which will help us determine power consumption using other loads.

In this case, 0.93 = 8/(8 +RON)  => RON = 0.6Ω Note that is the sum of output resistance for OUTP + OUTN.  So, for 4Ω, the efficiency would be 4Ω/(4Ω+0.6Ω) = 0.869

Based on the above, you should be able to derive the efficiency for any load and, based on your expected output power, derive the input power and input current draw.

• Actually input current and output current is unknown to me ,this is what i am trying to know.
expecting total load to be around 4ohm at the output side.
Please find the below snap for reference and help me to know the output current delivered and input current required.

• If there is no voltage driven on the output, you can see from the above equations that the input current will be only the quiescent current (2.7mA).

To really answer your question, we need to know the output signal you are intending to deliver to the load.

If you are driving an output voltage, the output current will be VOUT/4Ω = IOUT.  You should be able to plug into all of the already provided equations above to solve for any of the relevant parameters.