M27C64A STMICROELECTRONICS [STMicroelectronics], M27C64A Datasheet - Page 7

• Manufacturer Part Number: M27C64A
• Description: 64K (8K x 8) UV EPROM and OTP ROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Figure 6. Programming and Verify Modes AC Waveforms
Figure 7. Programming Flowchart
YES
NO
> 25
FAIL
++n
V CC
A0-A12
Q0-Q7
V PP
E
P
G
V CC = 6V, V PP = 12.5V
CHECK ALL BYTES
P = 3ms Pulse by n
NO
2nd: V CC = 4.2V
1st: V CC = 6V
P = 1ms Pulse
VERIFY
n = 1
Addr
Last
YES
YES
tVPHPL
tVCHPL
NO
tQVPL
tAVPL
tELPL
tPLPH
++ Addr
DATA IN
PROGRAM
AI01167
VALID
tPHQX
Programming
When delivered (and after each erasure for UV
EPROM), all bits of the M27C64A are in the “1”
state. Data is introduced by selectively program-
ming ”0s” into the desired bit locations. Although
only “0s” will be programmed, both “1s” and “0s”
can be present in the data word. The only way to
change a “0” to a ”1” is by die exposition to ultra-
violet light (UV EPROM). The M27C64A is in the
programming mode when V
E and P are at TTL-low. The data to be programmed
is applied 8 bits in parallel to the data output pins.
The levels required for the address and data inputs
are TTL. V
High Speed Programming
The high speed programming algorithm, described
in the flowchart, rapidly programs the M27C64A
using an efficient and reliable method, particularly
suited to the production programming environ-
ment. An individual device will take around1 minute
to program.
Program Inhibit
Programming of multiple M27C64A in parallel with
different data is also easily accomplished. Except
for E, all like inputs including G of the parallel
M27C64A may be common. A TTL low level pulse
applied to a M27C64A E input, with P low and V
tQXGL
VERIFY
tGLQV
DATA OUT
CC
is specified to be 6V
tGHQZ
tGHAX
pp
input is at 12.5V, and
AI00779
0.25V.
M27C64A
7/11
PP