M27W401-80XN6TR STMicroelectronics, M27W401-80XN6TR Datasheet - Page 8

• Manufacturer Part Number: M27W401-80XN6TR
• Description: 4 Mbit 512Kb x 8 Low Voltage UV EPROM and OTP EPROM
• Manufacturer: STMicroelectronics

M27W402
Figure 6. Programming and Verify Modes AC Waveforms
Figure 7. Programming Flowchart
8/15
YES
NO
= 25
FAIL
++n
V CC
A0-A17
Q0-Q15
V PP
E
G
V CC = 6.25V, V PP = 12.75V
CHECK ALL WORDS
NO
2nd: V CC = 2.7V
E = 100 s Pulse
1st: V CC = 5V
VERIFY
n = 0
Addr
Last
YES
YES
tVPHEL
tVCHEL
NO
tQVEL
tAVEL
tELEH
DATA IN
++ Addr
PROGRAM
AI00726D
VALID
tEHQX
PRESTO II Programming Algorithm
PRESTO II Programming Algorithm allows the
whole array to be programmed with a guaranteed
margin, in a typical time of 26.5 seconds. Pro-
gramming with PRESTO II consists of applying a
sequence of 100 s 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 V
higher than 3.6V, provides necessary margin to
each programmed cell.
Program Inhibit
Programming of multiple M27W402s in parallel
with different data is also easily accomplished. Ex-
cept for E, all like inputs including G of the parallel
M27W402 may be common. A TTL low level pulse
applied to a M27W402’s E input, with V
12.75V, will program that M27W402. A high level
E input inhibits the other M27W402s 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 V
tQXGL
IL
, E at V
VERIFY
tGLQV
DATA OUT
IH
, V
PP
at 12.75V and V
tGHQZ
tGHAX
AI00730
CC
at 6.25V.
CC
PP
much
at