HB288032MM1 Datasheet, PDF (72/80 Pages) Hitachi Semiconductor – MultiMediaCard 32 MByte

HB288032MM1
Bus Signal Line Load
The total capacitance C_L of each line of the MultiMediaCard bus is the sum of the bus master capacitance
C_HOST, the bus capacitance C_BUS itself and the capacitance C_CARD of each card connected to this line:
= + + C_L C_HOST C_BUS N*C_CARD
where N is the number of connected cards. Requiring the sum of the host and bus capacitance’s 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:
Parameter
Pull-up resistance for CMD
Pull-up resistance for DAT
Bus signal line capacitance
Symbol Min
R_CMD
4.7
R_DAT
50
C_L
—
Bus signal line capacitance
C_L
—
Single card capacitance
C_CARD
—
Maximum signal line inductance
—
Max
100
100
250
100
7
16
Unit
kΩ
kΩ
pF
pF
pF
nH
Remark
to prevent bus floating
to prevent bus floating
f_PP ≤ 5 MHz,
30 cards
f_PP ≤ 20 MHz,
10 cards
f_PP ≤ 20 MHz
72