Datasheet

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MAX98307/MAX98308
3.3W Mono Class DG Multilevel Audio Amplifier
The Class DG multilevel efficiency compares favor-
ably with Class AB and Class G amplifiers as shown in
Figure 2. Note that efficiency at 1W is 85%.
EMI Filterless Output Stage
Traditional Class D amplifiers require the use of external
LC filters, or shielding, to meet electromagnetic-interfer-
ence (EMI) regulation standards. The active emissions
limiting edge-rate control circuitry and Class DG multilev-
el modulation scheme reduce EMI emissions without the
need for external filtering components, while maintaining
high efficiency (see Figure 3).
Amplifier Current Limit
If the output current of the speaker amplifier exceeds the
current limit, the ICs disable the outputs for approximate-
ly 100Fs. After 100Fs, the outputs are reenabled. If the
fault condition still exists, the ICs continue to disable and
reenable the outputs until the fault condition is removed.
Figure 2. Class DG Multilevel vs. Typical Class G and Class
AB Amplifier Efficiency
Figure 3. EMI Performance with V
PVDD
= 5V, 12in of Speaker Cable, No Output Filter
EFFICIENCY vs. OUTPUT POWER
MAX98307 fig02
OUTPUT POWER (W)
EFFICIENCY (%)
1.81.61.2 1.40.4 0.6 0.8 1.00.2
10
20
30
40
50
60
70
80
90
0
0 2.0
MAX98307/MAX98308
CLASS DG MULTILEVEL AMPLIFIER
CLASS AB AMPLIFIER
CLASS G AMPLIFIER
V
PVDD
= 5V
f
IN
= 1kHz
1000
-10
10
30
50
70
90
200 300 400 500
EN55022B LIMIT
HORIZONTAL
VERTICAL
600 700 800 900 1000
FREQUENCY (MHz)
EMISSIONS LEVEL (dBµV/m)