MAX97000EWA+ MAXIM [Maxim Integrated Products], MAX97000EWA+ Datasheet - Page 20

• Manufacturer Part Number: MAX97000EWA+
• Description: Audio Subsystem with Mono Class D Speaker and Class H Headphone Amplifier
• Manufacturer: MAXIM [Maxim Integrated Products]

Audio Subsystem with Mono Class D
Speaker and Class H Headphone Amplifier
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Traditional Class D amplifiers require the use of external
LC filters or shielding to meet EN55022B electromag-
netic-interference (EMI) regulation standards. Maxim’s
patented active emissions limiting edge-rate control
circuitry and spread-spectrum modulation reduces EMI
emissions, while maintaining up to 87% efficiency.
Maxim’s patented spread-spectrum modulation mode
Figure 4. EMI with 15cm of Speaker Cable
Ultra-Low EMI Filterless Output Stage
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-10
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0
300
30
350
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550
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FREQUENCY (MHz)
FREQUENCY (MHz)
600
160
650
flattens wideband spectral components, while propri-
etary techniques ensure that the cycle-to-cycle variation
of the switching period does not degrade audio repro-
duction or efficiency. The MAX97000’s spread-spectrum
modulator randomly varies the switching frequency by
Q20kHz around the center frequency (250kHz). Above
10MHz, the wideband spectrum looks like noise for EMI
purposes (see Figure 4).
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700
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750
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850
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900
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950
1000
300