MMC interface

Circuit Protection of MMC Interface

Design Notes:

Protection Application:
For typical Multi Media Card (MMC) circuits, the data transfer rate is less than 20 Mbps, so protection devices with capacitance values less than 40 pF can be used. The lines to be protected against ESD include SCK, SI, SO, CS, Reset, WP and Ready.
Solution Description:
As shown at the left (top), discrete multilayer varistors can be used for layout flexibility. However, if part count reduction or board space savings are most important, then TVS diode arrays (left, middle) are recommended. Lastly, if the data rate will be greater than 200 Mbps, then PulseGuard suppressors should be used.
Companion Solutions:
Does not apply.
Regulatory Issues:
The IEC 61000-4-2 will be the most appropriate standard that applies for this port. It supplies a test method for verifying that the end product is not susceptible to ESD events.
Unique Features:
Does not apply.
Application Warnings:
Does not apply.