X28C512 Datasheet, PDF (9/25 Pages) Xicor Inc. – 5 Volt, Byte Alterable E2PROM

X28C512/X28C513
SYSTEM CONSIDERATIONS
Because the X28C512/513 is frequently used in large
memory arrays it is provided with a two line control
architecture for both read and write operations. Proper
usage can provide the lowest possible power dissipation
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.
Because the X28C512/513 has two power modes,
standby and active, proper decoupling of the memory
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_CC and V_SS at each device. Depend-
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_CC and V_SS for each
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.
Active Supply Current vs. Ambient Temperature
14
V_CC = 5V
13
12
11
10
9
8
–55
–10
+35
+80 +125
AMBIENT TEMPERATURE (°C)
3856 ILL F24
Standby Supply Current vs. Ambient Temperature
0.24
0.22
V_CC = 5V
0.2
0.18
0.16
0.14
0.12
0.1
–55
–10
+35
+80 +125
AMBIENT TEMPERATURE (°C)
3856 ILL F26
I_CC (RD) by Temperature over Frequency
70
5.0 V_CC
60
–55°C
50
+25°C
+125°C
40
30
20
10
0
3
6
9
12
FREQUENCY (MHz)
15
3856 ILL F25
9