2
PIN NAMES DEVICE OPERATION
The UT7Q512 has three control inputs called Enable 1 (E), Write
Enable (W), and Output Enable (G); 19 address inputs, A(18:0);
and eight bidirectional data lines, DQ(7:0). The E Device Enable
controls device selection, active, and standby modes. Asserting
E enables the device, causes I
DD
to rise to its active value, and
decodes the 19 address inputs to select one of 524,288 words in
the memory. W controls read and write operations. During a
read cycle, G must be asserted to enable the outputs.
Table 1. Device Operation Truth Table
Notes:
1. “X” is defined as a “don’t care” condition.
2. Device active; outputs disabled.
READ CYCLE
A combination of W greater than V
IH
(min), G and E less than
V
IL
(max) defines a read cycle. Read access time is measured
from the latter of Device Enable, Output Enable, or valid address
to valid data output.
SRAM read Cycle 1, the Address Access in figure 3a, is initiated
by a change in address inputs while the chip is enabled with G
asserted and W deasserted. Valid data appears on data outputs
DQ(7:0) after the specified t
AVQV
is satisfied. Outputs remain
active throughout the entire cycle. As long as Device Enable and
Output Enable are active, the address inputs may change at a
rate equal to the minimum read cycle time (t
AVAV
).
SRAM read Cycle 2, the Chip Enable-Controlled Access in
figure 3b, is initiated by E going active while G remains asserted,
W remains deasserted, and the addresses remain stable for the
entire cycle. After the specified t
ETQV
is satisfied, the eight-bit
word addressed by A(18:0) is accessed and appears at the data
outputs DQ(7:0).
SRAM read Cycle 3, the Output Enable-Controlled Access in
figure 3c, is initiated by G going active while E is asserted, W
is deasserted, and the addresses are stable. Read access time is
t
GLQV
unless t
AVQV
or t
ETQV
have not been satisfied.
A(18:0) Address
DQ(7:0) Data Input/Output
E Chip Enable
W Write Enable
G Output Enable
V
DD
Power
V
SS
Ground
1 36
2 35
3 34
4 33
5 32
6 31
7 30
8 29
9 28
10 27
11 26
12 25
13 24
14 23
15 22
16 21
17 20
18 19
Figure 2a. UT7Q512 100ns SRAM Shielded
Package Pinout (36)
NC
A15
A17
W
A13
A8
A9
A11
V
SS
V
DD
G
A10
E
DQ7
DQ6
DQ5
DQ4
NC
A18
A16
A14
A12
A7
A6
A5
A4
V
DD
V
SS
A3
A2
A1
A0
DQ0
DQ1
DQ2
DQ3
1 32
2 31
3 30
4 29
5 28
6 27
7 26
8 25
9 24
10 23
11 22
12 21
13 20
14 19
15 18
16 17
Figure 2b. UT7Q512 100ns SRAM
Package Pinout (32)
V
DD
A15
A17
W
A13
A8
A9
A11
G
A10
E
DQ7
DQ6
DQ5
DQ4
DQ3
A18
A16
A14
A12
A7
A6
A5
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
V
SS
G W E I/O Mode Mode
X
1
X 1 3-state Standby
X 0 0 Data in Write
1 1 0 3-state
Read
2
0 1 0 Data out Read