AC Programming Characteristics

Sym-

bol

Parameter

Test

Conditions*

(1)

Limits

Units

Min

Max

Address Setup Time

2

OE Setup Time

2

Data Setup Time

2

Address Hold Time

0

Data Hold Time

2

OE High to

Output Float Delay

(2)

0130

ns

2

2

CE Program Pulse Width

(3)

95

105

Data Valid from OE

(2)

150

ns

During Programming

50

ns

*AC Conditions of Test:

Input Rise and Fall Times (10% to 90%)...........20 ns

Input Pulse Levels................................0.45V to 2.4V

Input Timing Reference Level...............0.8V to 2.0V

Output Timing Reference Level............0.8V to 2.0V

2. This parameter is only sampled and is not 100%

tested. Output Float is defined as the point where

data is no longer driven —see timing diagram.

3. Program Pulse width tolerance is 100

Atmel’s 27LV256A Integrated

Codes

Pins

Hex

Data

A0

O7 O6 O5 O4 O3 O2 O1 O0

Manufacturer

00

0011110

1E

Device Type

11

0001100

8C

Note:

1. The AT27LV256A has the same Product Identification

Code as the AT27C256R. Both are programming

compatible.

Rapid Programming Algorithm

A 100

µs CE pulse width is used to program. The address

raised to 13.0V. Each address is first programmed with

one 100

µs CE pulse without verification. Then a verifica-

tion / reprogramming loop is executed for each address.

In the event a byte fails to pass verification, up to 10 suc-

cessive 100

µs pulses are applied with a verification after

each pulse. If the byte fails to verify after 10 pulses have

been applied, the part is considered failed. After the byte

verifies properly, the next address is selected until all have

5.0V. All bytes are read again and compared with the

original data to determine if the device passes or fails.

3-82

AT27LV256A