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MeiG Smart product technical information
SLM500 Hardware Design Guide Page 58
frequency interference.
path of VBAT as much as possible.
5.2.4. MIPI
MIPI is a high-speed signal line. Users must pay attention to protection during the
layout stage, so that they are away from the signal lines that are easily interfered. The GND
processing must be performed on the upper and lower sides, and the traces are differential
pairs. 100 ohm differential impedance matching is performed. Ensure impedance
consistency and do not bridge different GND planes as much as possible.
The MIPI interface selects a small-capacity TVS when selecting an ESD device. It is
recommended that the parasitic capacitance be less than 1pF.
The MIPI routing requirements are as follows:
The total length of the cable does not exceed 305mm
It is required to control 100 ohm differential impedance with an error of ±10%.
The error of the differential line length within the group is controlled within 1mm.
The length error between groups is controlled within 2 mm.
5.2.5. USB
The module supports high-speed USB interface at a rate of 480Mbps. The user recommends
adding a common-mode inductor during the schematic design phase to effectively suppress
EMI interference. If you need to increase the static protection, please select a TVS tube with a
parasitic capacitance of less than 1pF. Please refer to the following notes when planning
Layout:
g function, please note that the VBUS cable is as wide as possible.
Table 5.1: Internal USB cable length of the module
Pin
Signal
Length mm)
Length Error（P-N）
14
USB_HS_DP
33.0
0.3mm
13
USB_HS_DM
33.3
5.2.6.Audio
The module supports 3 analog audio signals. Analog signals are susceptible to interference
from high speed digital signals. So stay away from high-speed digital signal lines. The module
supports the GSM system, and the GSM signal can interfere with the audio by coupling and
conduction. Users can add 33pF and 10pF capacitors to the audio path to filter out coupling
interference. The 33pF capacitor mainly filters out the interference of the GSM850/EGSM900