max98308ewc+ Maxim Integrated Products, Inc., max98308ewc+ Datasheet - Page 2

• Manufacturer Part Number: max98308ewc+
• Description: 3.3w Mono Class Dg Multilevel Audio Amplifier
• Manufacturer: Maxim Integrated Products, Inc.

Use capacitors with an equivalent series resistance
(ESR) less than 50mI for optimum performance. Low-
ESR ceramic capacitors minimize the output resistance
of the charge pump. For best performance over the
extended temperature range, select capacitors with an
X7R dielectric and a rated voltage of at least 6.3V.
The value of the charge-pump flying capacitor affects
the load regulation and output resistance of the charge
pump. A charge-pump flying capacitor value that is too
small (less than 1FF) degrades the amplifier’s ability to
provide sufficient current drive. Increasing the value of
this flying capacitor and decreasing the ESR improves
load regulation and reduces the charge-pump output
impedance, which improves the output power and effi-
ciency of the amplifier. A 4.7FF or greater value, low ESR
capacitor is recommended.
The charge-pump hold capacitor value and ESR directly
affect the ripple at the charge-pump rail PVSS. Increasing
the charge-pump hold capacitor value reduces output
ripple. Likewise, decreasing the ESR of this capacitor
reduces both ripple and output resistance. A 10FF or
greater value, low ESR capacitor is recommended.
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
increases. At higher current, the resistance of the output
traces decrease the power delivered to the load. For
example, if 2W is delivered from the device output to an
8I load through 100mI of total speaker trace, 1.97W is
delivered to the speaker. If power is delivered through
10mI of total speaker trace, 1.998W is delivered to the
speaker. Wide output, supply, and ground traces also
improve the power dissipation of the device.
3.3W Mono Class DG Multilevel Audio Amplifier
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Charge-Pump Capacitor Selection
Charge-Pump Flying Capacitor
Charge-Pump Hold Capacitor
Layout and Grounding
The ICs are inherently designed for excellent RF immu-
nity. For best performance, add ground fills around all
signal traces on top or bottom PCB planes.
Class DG multilevel amplifiers provide much better effi-
ciency and thermal performance than a comparable Class
AB or Class G amplifiers. However, the system’s thermal
performance must be considered with realistic expecta-
tions and include consideration of many parameters. This
section examines Class DG multilevel amplifiers using
general examples to illustrate good design practices.
The exposed pad is the primary route of keeping heat
away from the IC. With a bottom-side exposed pad, the
PCB and its copper becomes the primary heatsink for
the Class DG multilevel amplifier. Solder the exposed
pad to a large copper polygon. Add as much copper
as possible from this polygon to any adjacent pin on
the amplifier as well as to any adjacent components,
provided these connections are at the same potential.
These copper paths must be as wide as possible. Each
of these paths contributes to the overall thermal capabili-
ties of the system.
The copper polygon to which the exposed pad is
attached should have multiple vias to the opposite side
of the PCB. Make this polygon as large as possible within
the system’s constraints for signal routing.
For the latest application details on WLP construction,
dimensions, tape carrier information, PCB techniques,
bump-pad layout, and recommended reflow temperature
profile, as well as the latest information on reliability test-
ing results, refer to Maxim Application Note 1891: Wafer-
Level Packaging (WLP) and Its Applications.
Note: All devices operate over the -40°C to +85°C temperature
range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
**Future product–contact factory for availability.
MAX98307ETE+
MAX98308EWC+**
MAX98307/MAX98308
PART
MAX98307 (TQFN) Applications Information
MAX98308 (WLP) Applications Information
Ordering Information
GAIN SET
External
Thermal Considerations
Internal
PIN-PACKAGE
16 TQFN-EP*
12 WLP