Rainbow Electronics W27L010 - Manual (Page 2)

Preliminary W27L010
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FUNCTIONAL DESCRIPTION
Read Mode
Like conventional UVEPROMs, the W27L010 has two control functions, both of which produce data at
the outputs.
CE is for power control and chip select. OE controls the output buffer to gate data to the output pins.
When addresses are stable, the address access time (T ACC ) is equal to the delay from CE to output
(T CE ), and data are available at the outputs T OE after the falling edge of OE , if T ACC and T CE timings
are met.
Erase Mode
The erase operation is the only way to change data from "0" to "1." Unlike conventional UVEPROMs,
which use ultraviolet light to erase the contents of the entire chip (a procedure that requires up to half
an hour), the W27L010 uses electrical erasure. Generally, the chip can be erased within 100 mS by
using an EPROM writer with a special erase algorithm.
Erase mode is entered when V PP is raised to V PE (14V), V CC = V CE (5V), CE low, OE high, A9 =
V HH (14V), A0 low , and all other address pins low and data input pins high. Pulsing PGM low starts
the erase operation.
Erase Verify Mode
After an erase operation, all of the bytes in the chip must be verified to check whether they have been
successfully erased to "1" or not. The erase verify mode automatically ensures a substantial erase
margin. This mode will be entered after the erase operation if V
PP = V PE (14V), CE low, and OE low ,
PGM high .
Program Mode
Programming is performed exactly as it is in conventional UVEPROMs, and programming is the only
way to change cell data from "1" to "0." The program mode is entered when V
PP is raised to V PP
(12V), V CC = V CP (5V), CE low , OE hig, the address pins equal the desired addresses, and the input
pins equal the desired inputs. Pulsing PGM low starts the programming operation.
Program Verify Mode
All of the bytes in the chip must be verified to check whether they have been successfully
programmed with the desired data or not. Hence, after each byte is programmed, a program verify
operation should be performed. The program verify mode automatically ensures a substantial
program margin. This mode will be entered after the program operation if V
PP = V PP (12V), CE low ,
OE low , and PGM high.
Erase/Program Inhibit
Erase or program inhibit mode allows parallel erasing or programming of multiple chips with different
data. When CE high , erasing or programming of non-target chips is inhibited, so that except for the
CE, the W27L010 may have common inputs.