Texas Instruments LM48861TMBD Evaluation Board LM48861TMBD/NOPB LM48861TMBD/NOPB Datenbogen
Produktcode
LM48861TMBD/NOPB
SNAS450B – JUNE 2008 – REVISED MAY 2013
PCB Layout Guidelines
Minimize trace impedance of the power, ground and all output traces for optimum performance. Voltage loss due
to trace resistance between the LM48861 and the load results in decreased output power and efficiency. Trace
resistance between the power supply and ground has the same effect as a poorly regulated supply, increased
ripple and reduced peak output power. Use wide traces for power supply inputs and amplifier outputs to minimize
losses due to trace resistance, as well as route heat away from the device. Proper grounding improves audio
performance, minimizes crosstalk between channels and prevents switching noise from interfering with the audio
signal. Use of power and ground planes is recommended.
to trace resistance between the LM48861 and the load results in decreased output power and efficiency. Trace
resistance between the power supply and ground has the same effect as a poorly regulated supply, increased
ripple and reduced peak output power. Use wide traces for power supply inputs and amplifier outputs to minimize
losses due to trace resistance, as well as route heat away from the device. Proper grounding improves audio
performance, minimizes crosstalk between channels and prevents switching noise from interfering with the audio
signal. Use of power and ground planes is recommended.
As described in the Common Mode Sense section, the LM48861 features a ground sensing feature. On the PCB
layout, connect the COM pin (pin D2) directly to the headphone jack ground and also to the left and right input
grounds. This will help correct any noise or any ground imbalance between the headphone return, input, and the
device ground, therefore improving audio reproduction.
layout, connect the COM pin (pin D2) directly to the headphone jack ground and also to the left and right input
grounds. This will help correct any noise or any ground imbalance between the headphone return, input, and the
device ground, therefore improving audio reproduction.
The charge pump capacitors and traces connecting the capacitor to the device should be kept away from the
input and output traces to avoid any switching noise injected into the input or output.
input and output traces to avoid any switching noise injected into the input or output.
Demo Board Schematic and Layout
Figure 18. Top Silkscreen Layer
Figure 19. Top Solder Mask
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