DEVICE OPERATION
PIN NAMES
The UT28F256 has three control inputs: Chip Enable (CE),
Program Enable (PE), and Output Enable (OE); fifteen address
inputs, A(14:0); and eight bidirectional data lines, DQ(7:0).CE
is the device enable input that controls chip selection, active, and
standby modes. AssertingCE causes I DD to rise to its active value
A(14:0)
CE
Address
Chip Enable
OE
Output Enable
Program Enable
Data Input/Data Output
and decodes the fifteen address inputs to select one of 32,768
words in the memory. PE controls program and read operations.
During a read cycle, OE must be asserted to enable the outputs.
PE
DQ(7:0)
PIN CONFIGURATION
Table 1. Device Operation Truth Table 1
1
A14
A12
A7
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
DD
OE
X
0
PE
1
CE
1
I/O MODE
Three-state
Data Out
Data In
MODE
Standby
Read
2
PE
A13
A8
3
A6
A5
4
1
0
5
A9
1
0
0
Program
A4
A3
A2
6
A11
2
1
1
0
Three-state
7
OE
Read
8
A10
Notes:
A1
A0
9
CE
1. “X” is defined as a “don’t care” condition.
2. Device active; outputs disabled.
10
11
12
13
14
DQ7
DQ6
DQ0
DQ1
DQ2
DQ5
DQ4
V
DQ3
SS
ABSOLUTE MAXIMUM RATINGS 1
(Referenced to VSS
SYMBOL
VDD
)
PARAMETER
LIMITS
UNITS
DC supply voltage
-0.3 to 7.0
V
V
VI/O
TSTG
PD
Voltage on any pin
-0.5 to (VDD + 0.5)
Storage temperature
-65 to +150
1.5
°C
Maximum power dissipation
Maximum junction temperature
W
TJ
+175
°C
Thermal resistance, junction-to-case 2
DC input current
QJC
II
3.3
°C/W
mA
±10
Notes:
1. Stresses outside the listed absolute maximum ratings may cause permanent damage to the device. This is a stress rating only, and functional operation of the
device at these or any other conditions beyond limits indicated in the operational sections of this specification is not recommended. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
2. Test per MIL-STD-883, Method 1012, infinite heat sink.
2
AEROFLEX [ AEROFLEX CIRCUIT TECHNOLOGY ]
