MAX98300 Maxim Integrated Products, MAX98300 Datasheet - Page 9

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

DataSheet.in
The MAX98300 features a low-power shutdown mode,
drawing less than 0.1FA of supply current. Drive SHDN
low to put the MAX98300 into shutdown.
The MAX98300 speaker amplifier features Maxim’s com-
prehensive click-and-pop suppression. During startup,
the click-and-pop suppression circuitry reduces any
audible transient sources internal to the device. When
entering shutdown, the differential speaker outputs ramp
down to PGND quickly and simultaneously.
Traditional Class D amplifiers require an output filter.
The filter adds cost, size, and decreases efficiency and
THD+N performance. The MAX98300’s filterless modula-
tion scheme does not require an output filter (Figure 1).
Because the switching frequency of the MAX98300 is
well beyond the bandwidth of most speakers, voice coil
movement due to the switching frequency is very small.
Use a speaker with a series inductance > 10FH. Typical
8I speakers exhibit series inductances in the 20FH to
100FH range.
PVDD powers the speaker amplifier. PVDD ranges
from 2.6V to 5.5V. Bypass PVDD with a 0.1FF and 10FF
capacitor to PGND. Apply additional bulk capacitance
at the device if long input traces between PVDD and the
power source are used.
The input-coupling capacitor (C
amplifier’s internal input resistance (R
pass filter that removes the DC bias from the incoming
signal. These capacitors allow the amplifier to bias the
signal to an optimum DC level.
Speaker Amplifier Power Supply Input (PVDD)
Applications Information
_______________________________________________________________________________________
Filterless Class D Operation
Click-and-Pop Suppression
Component Selection
IN
), in conjunction with the
IN
), forms a high-
Input Filtering
Shutdown
Mono 2.6W Class D Amplifier
Assuming zero source impedance with a gain setting of
A
with a gain setting of A
with a gain setting of A
where f
tors with adequately low voltage-coefficient for best low-
frequency THD performance.
Proper layout and grounding are essential for optimum
performance. Good grounding improves audio perfor-
mance and prevents switching noise from coupling into
the audio signal.
Use wide, low-resistance output traces. As load imped-
ance decreases, the current drawn from the device
outputs increase. At higher current, the resistance of the
output traces decreases the power delivered to the load.
For example, if 2W is delivered from the speaker output
to a 4I load through a 100mI trace, 49mW is consumed
in the trace. If power is delivered through a 10mI trace,
only 5mW is consumed in the trace. Wide output, supply,
and ground traces also improve the power dissipation of
the device.
The MAX98300 is inherently designed for excellent RF
immunity. For best performance, add ground fills around
all signal traces on top or bottom PCB planes.
The MAX98300 TDFN-EP package features an exposed
thermal pad on its underside. This pad lowers the pack-
age’s thermal resistance by providing a heat conduction
path from the die to the PCB. Connect the exposed ther-
mal pad to the ground plane by using a large pad and
multiple vias.
V
= 6dB, 9dB, or 12dB, C
-3dB
is the -3dB corner frequency. Use capaci-
C
C
C
IN
IN
IN
V
V
=
=
=
= 3dB, C
= 0dB, C
f
f
f
IN
−
−
−
5.7
3dB
3dB
3dB
Layout and Grounding
8
4
is:
[ F]
[ F]
[ F]
µ
µ
µ
IN
IN
is:
is:
9