2
PIN NAMES
DEVICE OPERATION
Each die in the UT8CR512K32 has three control inputs called
Enable (E), Write Enable (W), and Output Enable (G); 19
address inputs, A(18:0); and eight bidirectional data lines,
DQ(7:0). The device enable (E) 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 each memory die by selecting the 2,048,000 byte of
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 VIH (min) with E and G less
than VIL (max) defines a read cycle. Read access time is
measured from the latter of device enable, output enable, or valid
address to valid dat a ou tput.
SRAM read Cycle 1, the Address Access is initiated by a change
in address inputs while the chip is enabled with G asserted and
W deasserted. V alid data appears on data outputs DQn(7:0) after
the specified tAVQV 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 (tAVAV).
SRAM read Cycle 2, the Chip Enable-controlled Access 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 tETQV is satisfied, the eight- bit word
addressed by A(18:0) is accessed and appears at the data outputs
DQn(7:0).
SRAM read Cycle 3, the Output Enable-controlled Access is
initiated by G going active while E is asserted, W is deasserted,
and the addresses are stable. Read access time is tGLQV unless
tAVQV or tETQV have not been satisfied.
A(18:0) Address
DQ(7:0) Data Input/Output
EEnable
WWrite Enable
GOutput Enable
VDD1 Power (1.8V)
VDD2 Power (3.3V)
VSS Ground
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
68 67 66 65 64 63 62 61 6 0 59 58 57 56 555453 52
1819 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
Top View
DQ0(0)
DQ1(0)
DQ2(0)
DQ3(0)
DQ4(0)
DQ5(0)
DQ6(0)
DQ7(0)
V
SS
DQ0(1)
DQ1(1)
DQ2(1)
DQ3(1)
DQ4(1)
DQ5(1)
DQ6(1)
DQ7(1)
DQ0(2)
DQ1(2)
DQ2(2)
DQ3(2)
DQ4(2)
DQ5(2)
DQ6(2)
DQ7(2)
V
SS
DQ0(3)
DQ1(3)
DQ2(3)
DQ3(3)
DQ4(3)
DQ5(3)
DQ6(3)
DQ7(3)
V
DD1
A0
A1
A2
A3
A4
A5
E2
V
SS
E3
W0
A6
A7
A8
A9
A10
V
DD2
V
DD2
A11
A12
A13
A14
A15
A16
E0
G
E1
A17
W1
W2
W3
A18
V
DD1
V
SS
G W E I/O Mode Mode
XX13-stateStandby
X 0 0 Data in Write
1103-state
Read2
010Data outRead
Figure 2. 17ns SRAM Pinout 68)