MAX98300 Maxim Integrated Products, MAX98300 Datasheet - Page 8

• Manufacturer Part Number: MAX98300
• Description: Mono 2.6W Class D Amplifier
• Manufacturer: Maxim Integrated Products

DataSheet.in
Figure 1. EMI with 60cm of Speaker Cable and No Output Filtering
Mono 2.6W Class D Amplifier
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.
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 I
current overhead.
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.
8
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2
R loss of the MOSFET on-resistance and quiescent
Ultra-Low EMI Filterless Output Stage
Detailed Description
Class D Speaker Amplifier
-10
50
40
30
20
10
0
30
100
200
300
EN55022B LIMIT
400
FREQUENCY (MHz)
500
Table 1. Gain Control Configuration
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).
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.
The MAX98300 offers five programmable gain selections
through a single gain input (GAIN).
Connect to PVDD
Connect to PVDD through
100kI ±5%
Not connected
Connect to PGND through
100kI ±5%
Connect to PGND
600
GAIN PIN
700
800
900
1000
MAXIMUM GAIN (dB)
Speaker Current Limit
Selectable Gain
12
9
6
3
0