M27W401-100XN6TR View Datasheet(PDF) - STMicroelectronics

Part Name

Description

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M27W401-100XN6TR

4 Mbit (512Kb x 8) Low Voltage UV EPROM and OTP EPROM

STMicroelectronics 

M27W401

Figure 6. Programming and Verify Modes AC Waveforms

A0-A18

Q0-Q7

VPP

VCC

E

G

tAVPL

DATA IN

tQVEL

tVPHEL

tVCHEL

tELEH

VALID

tEHQX

DATA OUT

tGLQV

tQXGL

tGHQZ

tGHAX

PROGRAM

VERIFY

AI00725

Figure 7. Programming Flowchart

VCC = 6.25V, VPP = 12.75V

n=0

NO

++n

= 25

YES

E = 100µs Pulse

NO

VERIFY

YES

++ Addr

FAIL

Last NO

Addr

YES

CHECK ALL BYTES

1st: VCC = 5V

2nd: VCC = 2.7V

AI00760C

8/15

PRESTO II Programming Algorithm

PRESTO II Programming Algorithm allows the

whole array to be programmed with a guaranteed

margin, in a typical time of 52.5 seconds. Pro-

gramming with PRESTO II consists of applying a

sequence of 100µs program pulses to each byte

until a correct verify occurs (see Figure 7). During

programming and verify operation, a MARGIN

MODE circuit is automatically activated in order to

guarantee that each cell is programmed with

enough margin. No overprogram pulse is applied

since the verify in MARGIN MODE at VCC much

higher than 3.6V, provides the necessary margin

to each programmed cell.

Program Inhibit

Programming of multiple M27W401s in parallel

with different data is also easily accomplished. Ex-

cept for E, all like inputs including G of the parallel

M27W401 may be common. A TTL low level pulse

applied to a M27W401’s E input, with VPP at

12.75V, will program that M27W401. A high level

E input inhibits the other M27W401s from being

programmed.

Program Verify

A verify (read) should be performed on the pro-

grammed bits to determine that they were correct-

ly programmed. The verify is accomplished with G

at VIL, E at VIH, VPP at 12.75V and VCC at 6.25V.

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