X28LC512/X28LC513
SYSTEM CONSIDERATIONS
array is of prime concern. Enabling CE will cause
transient current spikes. The magnitude of these spikes
is dependent on the output capacitive loading of the I/
Os. Therefore, the larger the array sharing a common
bus, the larger the transient spikes. The voltage peaks
associated with the current transients can be sup-
pressed by the proper selection and placement of
decoupling capacitors. As a minimum, it is recom-
mended that a 0.1µF high frequency ceramic capacitor
be used between V and V at each device. Depend-
Because the X28LC512/513 is frequently used in large
memory arrays it is provided with a two line control
architecture for both read and write operations. Proper
usagecanprovidethelowestpossiblepowerdissipation
and eliminate the possibility of contention where mul-
tiple I/O pins share the same bus.
To gain the most benefit it is recommended that CE be
decoded from the address bus and be used as the
primary device selection input. Both OE and WE would
then be common among all devices in the array. For a
read operation this assures that all deselected devices
are in their standby mode and that only the selected
device(s) is outputting data on the bus.
CC
SS
ing on the size of the array, the value of the capacitor
may have to be larger.
In addition, it is recommended that a 4.7µF electrolytic
bulk capacitor be placed between V and V for each
CC
SS
eight devices employed in the array. This bulk capacitor
is employed to overcome the voltage droop caused by
the inductive effects of the PC board traces.
Because the X28LC512/513 has two power modes,
standby and active, proper decoupling of the memory
Active Supply Current vs. Ambient Temperature
I
(RD) by Temperature over Frequency
CC
40
7.5
3.3 V
CC
V
= 3.3V
CC
7
6.5
6
35
30
5.5
5
–55°C
25
20
+25°C
+125°C
4.5
4
–55
15
10
–10
+35
+80
+125
AMBIENT TEMPERATURE (°C)
3005 ILL F25
15
0
5
10
FREQUENCY (MHz)
3005 ILL F24
Standby Supply Current vs. Ambient Temperature
0.14
V
= 3.3V
CC
0.13
0.12
0.11
0.1
0.09
0.08
–10
+35
+80
+125
–55
AMBIENT TEMPERATURE (°C)
3005 ILL F26
9
XICOR [ XICOR INC. ]
