Datasheet

Analyzer
20Hz-20kHz
(a)BasicClass-AB
APA
Signal
Generator
PowerSupply
Analyzer
20Hz-20kHz
R
L
(b)Filter-FreeandTraditionalClass-D
Class-D APA
Signal
Generator
PowerSupply
R
L
Low-PassRC
Filter
Low-PassRC
Filter
(Seenote A)
TPA3106D1
www.ti.com SLOS516C –OCTOBER 2007–REVISED AUGUST 2010
A. For efficiency measurements with filter-free Class-D, R
L
should be an inductive load like a speaker.
Figure 34. Audio Measurement Systems
The device uses a modulation scheme that does not require an output filter for operation, but they do sometimes
require an RC low-pass filter when making measurements. This is because some analyzer inputs cannot
accurately process the rapidly changing square-wave output and therefore record an extremely high level of
distortion. The RC low-pass measurement filter is used to remove the modulated waveforms so the analyzer can
measure the output sine wave.
Copyright © 2007–2010, Texas Instruments Incorporated Submit Documentation Feedback 25
Product Folder Link(s): TPA3106D1