max9759etet Maxim Integrated Products, Inc., max9759etet Datasheet - Page 11

• Manufacturer Part Number: max9759etet
• Description: Max9759 3.2w, High-efficiency, Low-emi, Filterless, Class D Audio Amplifier
• Manufacturer: Maxim Integrated Products, Inc.

The MAX9759 features a unique, patented spread-spec-
trum mode that reduces peak component energy in the
wideband spectrum, improving EMI emissions that may
be radiated by the speaker and cables by 5dB.
Figure 1. MAX9759 Outputs with an Input Signal Applied
Table 1. Operating Modes
SYNC INPUT
Clocked
FLOAT
GND
V
DD
V
V
V
IN+
OUT+
IN-
Spread-Spectrum Modulation (SSM) Mode
- V
3.2W, High Efficiency, Low-EMI, Filterless,
OUT-
OUT+
OUT-
______________________________________________________________________________________
FFM with f
FFM with f
SSM with f
FFM with f
t
ON(MIN)
S
S
S
S
= 1100kHz
= 1500kHz
= external clock frequency
= 1200kHz ±70kHz
MODE
t
SW
Class D Audio Amplifier
Proprietary techniques ensure that the cycle-to-cycle
variation of the switching period does not degrade audio
reproduction or efficiency (see the Typical Operating
Characteristics). Select SSM mode by setting SYNC =
V
±70kHz around the center frequency (1.2MHz). The
modulation scheme remains the same, but the period of
the sawtooth waveform changes from cycle to cycle
(Figure 2). Instead of a large amount of spectral energy
present at multiples of the switching frequency, the ener-
gy is now spread over a bandwidth that increases with
frequency. Above a few megahertz, the wideband spec-
trum looks like white noise for EMI purposes (Figure 3).
DD
. In SSM mode, the switching frequency varies by
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