Figure 11-4. SPI SD Card Design Example Diagram
NC
SPI SD CARD PROTECTION EXAMPLE
5
D5V0P4UR6SO
2
13
46
1
2
3
4
5
6
7
8
9
STD SD CARD (Option B)
MCU
SDO - MOSI
SCK
33
33
33
NOTE:
Ground connection on all TVS MUST be directly
connected to ground plane and not through a
trace to ground to minimize inductance. In addition,
they should
be located as close to the external SD card connector as
possible.
↑Transient
Suppressors
10K
3.3v
10K
0.01uf
Opt(B)
Chassis
(AC) Gnd
if available
(Preferred)
If chassis (AC) Gnd
not available
Opt(A)
100K
1k Ω@100Mhz, DC=0.15Ω, 1A
MI0805J102R-10
NOTE:
See appropriate MCU power
bypassing circuit configuration
illustrations in section 2.2
CS#
SDIx - MISO
I/O
NC
1
2
3
4
5
6
7
8
5
D5V0P4UR6SO
2
13
46
MICRO SD CARD
(Option A)
↑Transient
Suppressors
Opt(B)
Chassis
(AC) Gnd
if available
(Preferred)
If chassis (AC) Gnd
not available
Opt(A)
100K
33
NC
1nf
1k Ω@100Mhz, DC=0.15Ω, 1A
MI0805J102R-10
I/O
#CARD DET
#CARD DET
#CARD DET
33k
3.3v
11.3.1 Key SPI SD Card Protection Design Points
• The SD card receptacle must be connected to the chassis AC earth ground if possible, or through a 100k
resistor to digital ground to attenuate any potential ESD discharge event.
•
Signal termination resistors in this case are not required, because the ESD protection device CM1422-03CP has
a 100 Ohm series resistor as part of the ESD RC filter.
• All SD card signals are routed through the ESD RC filter.
There is comprehensive information available on ESD, EMI, or EFT on the web site that can be found in the
document: AN2587 - EMI, EMC, EFT, and ESD Circuit Design Consideration for 32-bit Microcontrollers, or on any of
the 32-bit product web pages, which are available under the tab Documentation > Application Notes.
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Serial Data Corruption Errors
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echnology Inc.
and its subsidiaries
Manual
DS70005439B-page 38
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