2

DEVICE OPERATION

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

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.

PIN NAMES

Table 1. Device Operation Truth Table

1

Notes:

1. “X” is defined as a “don’t care” condition.

2. Device active; outputs disabled.

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.

A14

A12

A7

A6

A5

A4

A3

A2

A1

A0

DQ0

DQ1

DQ2

PE

A13

A8

A9

A11

OE

A10

CE

DQ7

DQ6

DQ5

DQ4

DQ3

PIN CONFIGURATION

1

2

3

4

5

6

7

8

9

10

11

12

13

14

28

27

26

25

24

23

22

21

20

19

18

17

16

15

A(14:0)

Address

CE

Chip Enable

OE

Output Enable

PE

Program Enable

DQ(7:0)

Data Input/Data Output

OE

PE

CE

I/O MODE

MODE

X

1

1

Three-state

Standby

0

1

0

Data Out

Read

1

0

0

Data In

Program

1

1

0

Three-state

SYMBOL

PARAMETER

LIMITS

UNITS

V

DD

DC supply voltage

-0.3 to 7.0

V

Voltage on any pin

V

Storage temperature

-65 to +150

°C

P

D

Maximum power dissipation

1.5

W

Maximum junction temperature

+175

°C

Θ

JC

3.3

°C/W

I

I

DC input current

mA