Chapter 3 – SD Card Interface Description
Revision 2.2
SD Card Product Manual
© 2004 SanDisk Corporation
3-8
12/08/04
Table 3-5
Host and Bus Capacities
8
Parameter Symbol
Min.
Max.
Unit
Remark
Pull-up resistance
R
CMD,
R
DAT
10 100 k
Ω
Prevents bus floating
Bus signal line capacitance
C
L
---
250
pF
f
PP
< 5 MHz, 21 cards
Bus signal line capacitance
C
L
---
100
pF
Signal card capacitance
C
CARD
--- 10 pF
f
PP
< 20 MHz, 7 cards
Max. signal line inductance
---
---
16
nH
f
PP
<20 MHz
Pull-up resistance inside card (pin 1)
R
DAT3
10 90 k
Ω
May be used for card
detection
3.4.4
Bus Signal Levels
All signal levels are related to the supply voltage because the bus can have a variable
supply voltage (see Figure 3-6).
Figure 3-6
Bus Signal Levels
3.4.5
Open-drain Mode Bus Signal Level
To meet the requirements of the JEDEC specification JESD8-1A, the card input and output
voltages are within the specified ranges in Table 3-6 for any V
DD
of the allowed voltage
range.
Table 3-6
Input/Output Voltage
Parameter Symbol
Min. Max.
Unit
Conditions
Output high voltage
V
OH
0.75*V
DD
--- V
I
OH
= -100 uA@ V
DD
(minimum)
Output low voltage
V
OL
---
0.125*V
DD
V I
OL
= 100 uA@ V
DD
(minimum)
Input high voltage
V
IH
0.625*V
DD
V
DD
+0.3 V ---
Input low voltage
V
IL
V
SS
-0.3 0.25*V
DD
V ---
8
The total capacitance of CMD and DAT lines will consist of C
HOST
, C
BUS
, and one C
CARD
only because they are
connected separately to the SD Card host.
Input
Low
Level
Input
High
Level
Output
High
Level
Output
Low
Level
Undefined
V
DD
V
OH
V
IH
V
L
V
OL
V
SS
t
V