M27128A-20F6 STMICROELECTRONICS [STMicroelectronics], M27128A-20F6 Datasheet - Page 7

• Manufacturer Part Number: M27128A-20F6
• Description: NMOS 128K 16K x 8 UV EPROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Figure 6. Programming and Verify Modes AC Waveforms
Figure 7. Programming Flowchart
YES
NO
FAIL
> 25
++n
V CC
A0-A13
Q0-Q7
V PP
E
P
G
V CC = 6V, V PP = 12.5V
CHECK ALL BYTES
P = 3ms Pulse by n
V CC = 5V, V PP 5V
NO
P = 1ms Pulse
VERIFY
n = 1
Addr
Last
YES
YES
tVPHPL
tVCHPL
NO
tQVPL
tAVPL
tELPL
tPLPH
++ Addr
DATA IN
PROGRAM
AI00775B
VALID
tPHQX
DEVICE OPERATION (cont’d)
continually monitored to determine when it has
been successfully programmed. A flowchart of the
M27128A Fast Programming Algorithm is shown
on the last page. The Fast Programming Algorithm
utilizes two different pulse types: initial and over-
program.
The duration of the initial P pulse(s) is 1ms, which
will then be followed by a longer overprogram pulse
of length 3ms by n (n is equal to the number of the
initial one millisecond pulses applied to a particular
M27128A location), before a correct verify occurs.
Up to 25 one-millisecond pulses per byte are pro-
vided for before the over program pulse is applied.
The entire sequence of program pulses and byte
verifications is performed at V
12.5V. When the Fast Programming cycle has been
completed, all bytes should be compared to the
original data with V
Program Inhibit
Programming of multiple M27128A’s in parallel with
different data is also easily accomplished. Except
for E, all like inputs (including G) of the parallel
M27128A may be common. A TTL low pulse ap-
plied to a M27128A’s E input, with V
program that M27128A. A high level E input inhibits
the other M27128As from being programmed.
tQXGL
VERIFY
tGLQV
DATA OUT
CC
= 5 and V
tGHQZ
tGHAX
CC
AI00772
PP
= 6V and V
= 5V.
PP
= 12.5V, will
M27128A
PP
7/10
=