X20C17
PIN CONFIGURATION
Output Enable (OE)
The Output Enable input controls the data output buff-
ers and is used to initiate read and recall operations.
Output Enable LOW disables a store operation regard-
less of the state of CE, WE.
Plastic
A
A
A
A
A
1
24
23
22
21
20
19
18
17
16
15
14
13
V
A
A
7
6
5
4
3
CC
8
2
Data In/Data Out (I/O –I/O )
0
7
3
9
Data is written to or read from the X20C17 through the
I/O pins. The I/O pins are placed in the high impedance
state when either CE or OE is HIGH.
WE
OE
4
5
A
A
A
6
A
2
1
0
10
X20C17
7
CE
Write Enable (WE)
8
I/O
I/O
I/O
5
4
3
The Write Enable input controls the writing of data to
the static RAM.
9
I/O
I/O
I/O
0
1
10
11
12
PIN NAMES
I/O2
2
V
SS
I/O
1
Symbol
A –A
Description
Address Inputs
0
10
SOIC
I/O –I/O
0
Data Input/Output
Write Enable
Chip Enable
Output Enable
+5V
7
WE
CE
OE
NC
OE
A
1
2
28
27
26
25
24
23
22
21
20
19
18
17
16
15
10
CE
I/O
WE
3
7
A
9
I/O
I/O
I/O
I/O
4
V
6
5
4
CC
NC
5
V
Ground
SS
A
8
6
X20C17
V
7
CC
DEVICE OPERATION
3
8
V
SS
NC
The CE, OE, and WE inputs control the X20C17 opera-
tion. The X20C17 byte-wide NOVRAM uses a 2-line
control architecture to eliminate bus contention in a
system environment. The I/O bus will be in a high
impedance state when either OE or CE is HIGH.
9
I/O
2
A
7
A
6
10
11
12
13
14
I/O1
A
5
I/O
0
NC
A
0
A
4
A
1
RAM Operations
A
3
A
2
RAM read and write operations are performed as they
would be with any static RAM. A read operation
requires CE and OE to be LOW. A write operation
requires CE and WE to be LOW. There is no limit to the
number of read or write operations performed to the
RAM portion of the X20C17.
PIN DESCRIPTIONS
Addresses (A –A )
0
10
The Address inputs select an 8-bit memory location
during a read or write operation.
Memory Transfer Operations
There are two memory transfer operations: a recall
operation whereby the data stored in the E2PROM
array is transferred to the RAM array; and a store oper-
ation which causes the entire contents of the RAM
array to be stored in the E2PROM array.
Chip Enable (CE)
The Chip Enable input must be LOW to enable all read/
write operations. When CE is HIGH, power consump-
tion is reduced.
Characteristics subject to change without notice. 2 of 12
XICOR [ XICOR INC. ]
