MAX98300 データシートの表示（PDF） - Maxim Integrated
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MAX98300 Datasheet PDF : 14 Pages
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MAX98300
Mono 2.6W Class D Amplifier
Detailed Description
The MAX98300 features industry-leading quiescent cur-
rent, low-power shutdown mode, comprehensive click-
and-pop suppression, and excellent RF immunity.
The device offers Class AB audio performance with
Class D efficiency in a minimal board-space solution.
The Class D amplifier features spread-spectrum modula-
tion, edge-rate, and overshoot control circuitry that offers
significant improvements to switch-mode amplifier radi-
ated emissions.
The MAX98300 amplifier features click-and-pop sup-
pression that reduces audible transients on startup and
shutdown. The amplifier includes thermal overload and
short-circuit protection.
Class D Speaker Amplifier
The MAX98300 filterless Class D amplifier offers much
higher efficiency than Class AB amplifiers. The high
efficiency of a Class D amplifier is due to the switching
operation of the output stage transistors. Any power loss
associated with the Class D output stage is mostly due to
the I2R loss of the MOSFET on-resistance and quiescent
current overhead.
Ultra-Low EMI Filterless Output Stage
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 89% efficiency.
Maxim’s patented spread-spectrum modulation mode
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 MAX98300’s spread-spectrum
modulator randomly varies the switching frequency by
Q10kHz around the center frequency (300kHz). Above
10MHz, the wideband spectrum looks like noise for EMI
purposes (Figure 1).
Speaker Current Limit
If the output current of the speaker amplifier exceeds the
current limit (2A typ), the MAX98300 disables the out-
puts for approximately 130Fs. At the end of 130Fs, the
outputs are re-enabled. If the fault condition still exists,
the MAX98300 continues to disable and re-enable the
outputs until the fault condition is removed.
Selectable Gain
The MAX98300 offers five programmable gain selections
through a single gain input (GAIN).
Table 1. Gain Control Configuration
GAIN PIN
Connect to PVDD
Connect to PVDD through
100kI ±5%
Not connected
Connect to PGND through
100kI ±5%
Connect to PGND
MAXIMUM GAIN (dB)
12
9
6
3
0
50
EN55022B LIMIT
40
30
20
10
0
-10
30 100 200 300 400 500 600 700 800 900 1000
FREQUENCY (MHz)
Figure 1. EMI with 60cm of Speaker Cable and No Output Filtering
8
Maxim Integrated
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