max9796 Maxim Integrated Products, Inc., max9796 Datasheet - Page 26

• Manufacturer Part Number: max9796
• Description: Max9796 2.3w, High-power Class D Audio Subsystem With Directdrive Headphone Amplifiers
• Manufacturer: Maxim Integrated Products, Inc.

2.3W, High-Power Class D Audio Subsystem
with DirectDrive Headphone Amplifiers
Use capacitors with an ESR less than 100mΩ for opti-
mum performance. Low-ESR ceramic capacitors mini-
mize the output resistance of the charge pump. Most
surface-mount ceramic capacitors satisfy the ESR
requirement. For best performance over the extended
temperature range, select capacitors with an X7R dielec-
tric or better. Table 12 lists suggested manufacturers.
The value of the flying capacitor (C1) affects the output
resistance of the charge pump. A C1 value that is too
small degrades the device’s ability to provide sufficient
current drive, which leads to a loss of output voltage.
Increasing the value of C1 reduces the charge-pump out-
put resistance to an extent. Above 1µF, the on-resistance
of the switches and the ESR of C1 and C2 dominate.
The output capacitor value and ESR directly affect the
ripple at CPV
output ripple. Likewise, decreasing the ESR of C2
reduces both ripple and output resistance. Lower
capacitance values can be used in systems with low
maximum output power levels. See the Output Power
vs. Load Resistance and Charge-Pump Capacitor Size
graph in the Typical Operating Characteristics .
The CPV
impedance of the power supply and reduces the
impact of the MAX9796’s charge-pump switching tran-
sients. Bypass CPV
physically close to the CPV
for C3 that is equal to C1.
Proper layout and grounding are essential for optimum
performance. Use large traces for the power-supply
inputs and amplifier outputs to minimize losses due to
Table 12. Suggested Capacitor Manufacturers
26
Taiyo Yuden
TDK
Supply Bypassing, Layout, and Grounding
______________________________________________________________________________________
SUPPLIER
DD
bypass capacitor (C3) lowers the output
SS
. Increasing the value of C2 reduces
Charge-Pump Capacitor Selection
DD
CPV
with C3 to PGND and place it
DD
DD
and PGND. Use a value
Bypass Capacitor (C3)
Output Capacitor (C2)
Flying Capacitor (C1)
800-348-2496
847-803-6100
PHONE
847-925-0899
847-390-4405
parasitic trace resistance. Large traces also aid in mov-
ing heat away from the package. Proper grounding
improves audio performance, minimizes crosstalk
between channels, and prevents any switching noise
from coupling into the audio signal. Connect PGND and
GND together at a single point on the PCB. Route all
traces that carry switching transients away from GND
and the traces/components in the audio signal path.
Connect all of the power-supply inputs (CPV
and PV
tor to CPGND. Bypass V
GND. Bypass PV
a 0.1µF capacitor to PGND. Place the bypass capaci-
tors as close as possible to the MAX9796. Place a bulk
capacitor between PV
Use large, low-resistance output traces. Current drawn
from the outputs increase as load impedance decreas-
es. High output trace resistance decreases the power
delivered to the load. Large output, supply, and GND
traces allow more heat to move from the MAX9796 to the
PCB, decreasing the thermal impedance of the circuit.
For the latest application details on UCSP construction,
dimensions, tape carrier information, PCB techniques,
bump-pad layout, and recommended reflow tempera-
ture profile, as well as the latest information of reliability
testing results, refer to Application Note: UCSP—A
Wafer-Level Chip-Scale Package available on Maxim’s
website at www.maxim-ic.com/ucsp.
When operating at maximum output power, the UCSP
thermal dissipation can become a limiting factor. The
UCSP package does not dissipate heat as efficiently as
packages with a thermal pad. As a result, in some
applications, the thermal performance of the package
may limit performance.
PROCESS: BiCMOS
FAX
UCSP Applications Information
DD
) together. Bypass CPV
DD
UCSP Thermal Consideration
www.t-yuden.com
www.component.tdk.com
with a 1µF capacitor in parallel with
DD
and PGND, if needed.
DD
Chip Information
with a 1µF capacitor to
WEBSITE
DD
with a 1µF capaci-
DD
, V
DD
,