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Detailed Description

The MAX9788 Class G power amplifier with inverting

charge pump is the latest in linear amplifier technology.

The Class G output stage offers improved performance

over a Class AB amplifier while increasing efficiency to

extend battery life. The integrated inverting charge

pump generates a negative supply capable of deliver-

ing greater than 700mA.

The Class G output stage and the inverting charge

swing, up to two times greater than a traditional single-

supply linear amplifier.

Class G Operation

The MAX9788 Class G amplifier is a linear amplifier that

from the low to high supply range. For small signals,

ply range. In this range, the operation of the device

is identical to a traditional single-supply Class AB

amplifier where:

As the output signal increases so a wider supply is need-

ed, the device begins its transition to the higher supply

seamless transition between the low and high supply

ranges, both of the lower transistors are on so that:

As the output signal continues to increase, the transi-

tion to the high supply is complete. The device then

operates in the higher supply range, where the opera-

tion of the device is identical to a traditional dual-sup-

ply Class AB amplifier where:

During operation, the output common-mode voltage of

the MAX9788 adjusts dynamically as the device transi-

tions between supply ranges.

Utilizing a Class G output stage with an inverting

output swing with a 5V supply.

ON

P

N1

N2

ON

OFF

LOW SUPPLY RANGE OPERATION

ON

P

N1

N2

ON

ON

BTL CLASS G SUPPLY TRANSITION

SUPPLY TRANSITION

ON

P

N1

N2

OFF

ON

HIGH SUPPLY RANGE OPERATION

Figure 1. Class G Supply Transition