MAX9730 Maxim Integrated Products, MAX9730 Datasheet - Page 7

• Manufacturer Part Number: MAX9730
• Description: Class G Power Amplifier
• Manufacturer: Maxim Integrated Products

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The MAX9730 Class G power amplifier with inverting
charge pump is the latest in linear amplifier technolo-
gy. The Class G output stage offers the performance
of a Class AB amplifier while increasing efficiency to
extend battery life. The integrated inverting charge
pump generates a negative supply capable of deliver-
ing up to 500mA.
The Class G output stage and the inverting charge pump
allow the MAX9730 to deliver an output power that is up
to four times greater than a traditional single-supply linear
amplifier. This allows the MAX9730 to maintain 0.8W into
an 8Ω load as the battery rail collapses.
The MAX9730 Class G amplifier is a linear amplifier that
operates within a low (V
SV
from the low to high supply range. For small signals,
the device operates within the lower (V
Figure 1. Class G Supply Transition
ON
SS
) supply range. Figure 1 illustrates the transition
2.4W, Single-Supply, Class G Power Amplifier
P
LOW SUPPLY RANGE OPERATION
I
P
Class G Operation and Efficiency
I
P
SV
V
R
= I
_______________________________________________________________________________________
CC
L
SS
N1
Detailed Description
CC
I
N1
to GND) and high (V
N1
N2
ON
OFF
CC
ON
to GND) sup-
P
BTL CLASS G SUPPLY TRANSITION
CC
I
P
SUPPLY TRANSITION
to
I
P
= I
SV
V
N1
R
CC
L
SS
+ I
ply range. In this range, the operation of the device is
identical to a traditional single-supply Class AB amplifi-
er where:
As the output signal increases, so a wider supply is
needed, the device begins its transition to the higher sup-
ply range (V
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 MAX9730 adjusts dynamically as the device transi-
tions between supply ranges.
N2
I
I
N1
N2
N1
N2
CC
ON
ON
to SV
ON
I
LOAD
SS
I
I
LOAD
) for the large signals. To ensure a
LOAD
P
= I
HIGH SUPPLY RANGE OPERATION
I
N1
P
= I
= I
N1
N2
+ I
N2
I
P
SV
V
R
= I
CC
L
SS
N2
I
N2
N1
N2
OFF
ON
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