MultiMediaCard Product Manual
24
SanDisk MultiMediaCard Product Manual Rev. 2 © 2000 SANDISK CORPORATION
Bus Signal Line Load
The total capacitance CL of each line of the MultiMediaCard bus is the sum of the bus master
capacitance CHOST, the bus capacitance CBUS itself and the capacitance CCARD of each card
connected to this line:
CL = CHOST + CBUS + N
∗
CCARD
where N is the number of connected cards. Requiring the sum of the host and bus capacitances not to
exceed 30 pF for up to 10 cards, and 40 pF for up to 30 cards, the following values must not be exceeded:
P a r a m e t e r
Symbol
M i n .
M a x .
Unit
Remark
Pull-up resistance
RCMD
RDAT
50
100
k
Ω
To prevent bus floating
Bus signal line capacitance
CL
250
pF
fPP
#
5 MHz,
30 cards
Bus signal line capacitance
CL
100
pF
fPP
#
20 MHz,
10 cards
Single card capacitance
CCARD
7
pF
Maximum signal line inductance
16
nH
fPP
#
20 MHz
4.4.3
Bus Signal Levels
As the bus can be supplied with a variable supply voltage, all signal levels are related to the supply
voltage.
Input
High
Level
Input
Low
Level
Output
High
Level
Output
Low
Level
Undefined
V
V
DD
V
IH
V
IL
V
SS
t
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V
OH
V
OL
Figure 4-4 Bus Signal Levels