M27C4002-10B1X STMICROELECTRONICS [STMicroelectronics], M27C4002-10B1X Datasheet - Page 9

• Manufacturer Part Number: M27C4002-10B1X
• Description: 4 Mbit (256Kb x16) UV EPROM and OTP EPROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Figure 6. Programming and Verify Modes AC Waveforms
Figure 7. Programming Flowchart
YES
NO
FAIL
= 25
++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 = 4.2V
E = 100 s Pulse
1st: V CC = 6V
VERIFY
n = 0
Addr
Last
YES
YES
tVPHEL
tVCHEL
NO
tAVEL
tQVEL
tELEH
DATA IN
++ Addr
PROGRAM
AI00726C
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 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 provides nec-
essary margin to each programmed cell.
Program Inhibit
Programming of multiple M27C4002s in parallel
with different data is also easily accomplished. Ex-
cept for E, all like inputs including G of the parallel
M27C4002 may be common. A TTL low level
pulse applied to a M27C4002's E input, with V
at 12.75V, will program that M27C4002. A high
level E input inhibits the other M27C4002s 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
M27C4002
at 6.25V.
9/18
PP