Cirrus Logic CDB42L73 - Manual (Page 7)

DS882DB1 7
CDB42L73
2.8 CS42L73 Ultralow Power Mobile Audio and Telephony CODEC
The CS42L73 is a highly integrated, ultralow power, audio and telephony CODEC for portable applications.
It features microphone and line inputs; three bidirectional serial ports with high-performance ASRCs; and
headphone, line, and speaker amplifiers. A complete description of the CS42L73 can be found in its
datasheet, downloadable from
http://www.cirrus.com .
2.9 Performance Measurement Tips
• Low frequency THD+N and common mode rejection performance may be improved by increasing the
capacitance of the DC-blocking capacitors on the line and microphone inputs (C81, C82, C83, C84, C85,
C86, C87).
• Interchannel isolation (crosstalk) performance of the CS42L73’s headphone output should be measured
with headphone loads connected between TP22 and GND (TP36), and between TP23 and GND (TP36).
These connection points provide the lowest impedance return paths for the headphone loads to reflect
the full headphone crosstalk performance of the CS42L73.
• Dynamic range and THD+N measurement of the CS35L01 (when J59 and J60 are shunted to the “AMP”
position) should be made with an external filter such as the AP AUX-0025 Switching Amplifier Measure-
ment Filter. Filters such as the AUX-0025 prevent switching noise of Class-D amplifiers from affecting
measurement accuracy of traditional audio analyzers.