Details

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BUY W27E257-12 https://www.utsource.net/itm/p/12606534.html

Parameter	Description	Value
Device Type	Non-Volatile Memory	2 Mbit (256 K x 8) Flash Memory
Package	Plastic Dual In-Line Package (PDIP)	28-Pin
Operating Voltage (Vcc)	Supply Voltage	2.7V to 3.6V
Standby Current (ISB)	Typical at Vcc = 3.0V, Ta = 25掳C	5 渭A
Active Current (IAV)	Typical at Vcc = 3.0V, Ta = 25掳C, 5 MHz	10 mA
Programming Time (tPROG)	Maximum Time for Programming a Single Byte	4 ms
Erase Time (tERS)	Maximum Time for Erasing a Sector	200 ms
Data Retention	Minimum Data Retention Time	10 years
Endurance	Maximum Number of Program/Erase Cycles per Sector	100,000 cycles
Operating Temperature (Ta)	Industrial Temperature Range	-40掳C to +85掳C
Storage Temperature (Tstg)	Storage Temperature Range	-65掳C to +150掳C
Organization	Memory Organization	256K x 8 bits
Sector Size	Sector Erase Size	64 Kbits (8 Kbytes)
Block Size	Block Erase Size	16 Mbits (2 Mbytes)
Access Time (tACC)	Maximum Access Time at Vcc = 3.0V, Ta = 25掳C, 5 MHz	70 ns
Write Protect Pin (WP)	Write Protect Function	Active Low, Disable Write Operations
Hold Pin (HOLD)	Suspend Operation Function	Active Low, Suspend Read/Write Operations
Package Marking	Device Identification	W27E257-12

Instructions:

1. Power Supply:

   • Connect the Vcc pin to a power supply within the specified range (2.7V to 3.6V).
   • Connect the GND pin to ground.

2. Address and Data Lines:

   • Connect the address lines (A0-A17) to the appropriate address bus.
   • Connect the data lines (D0-D7) to the appropriate data bus.

3. Control Signals:

   • Chip Select (CS#): Active low. When low, the device is selected.
   • Output Enable (OE#): Active low. When low, data outputs are enabled.
   • Write Enable (WE#): Active low. Used to initiate write operations.
   • Write Protect (WP#): Active low. When low, write operations are inhibited.
   • Hold (HOLD#): Active low. When low, ongoing operations are suspended.

4. Programming:

   • To program a byte, set the address and data lines, then pulse WE# low while CS# and OE# are low.
   • Ensure that the programming time (tPROG) is not exceeded.

5. Erasing:

   • To erase a sector, set the address lines to the start of the sector, then issue the appropriate erase command.
   • Ensure that the erase time (tERS) is not exceeded.

6. Read Operations:

   • To read data, set the address lines, then pulse OE# low while CS# is low.
   • Ensure that the access time (tACC) is respected.

7. Write Protect and Hold:

   • Use WP# to prevent accidental writes by setting it low.
   • Use HOLD# to suspend operations temporarily by setting it low.

8. Temperature Considerations:

   • Ensure that the operating temperature (Ta) remains within the specified range (-40掳C to +85掳C).
   • Store the device within the storage temperature range (-65掳C to +150掳C).

9. Endurance and Data Retention:

   • The device can withstand up to 100,000 program/erase cycles per sector.
   • Data retention is guaranteed for at least 10 years under normal operating conditions.

(For reference only)