User's Manual

VZ22Q LTE Module
V0.1
USI
Confidential Page 20 of 23
 LINE_IN_L/LINE_IN_R > 10 mils (15 mils is better)
 AUX_OUT/AUX_OUTN >10 mils (15mils is better)
 SPKOUT/ SPKOUTN > 20 mils (30 mils is better)
iv. The signal length from codec to input/output connector should be as short as possible.
v. The trace length difference between the differential signal (ex: MIC1P/N, SPK_OUT_R/
SPK_OUT_RN, ...etc) should be kept as small as possible. (better within 1 inch).
vi. The width between differential pair should be small (D≦10 mils).
vii. The space between each trace should better to be filled with copper which connect to analog
ground.
5.4.3 QFN32 Footprint Layout
The layout of PCB footprint for ALC5623 (QFN-32) can be seen in Figure 5-6. Note that
the ground pad in the center is important. It is suggested to connect to Digital ground. It makes
codec to have better performance.
Figure 5-6. ALC5623 PCB footprint