Details

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BUY AT29C257-90JC https://www.utsource.net/itm/p/12605024.html

Parameter	Description	Value	Unit
Device Type	Flash Memory
Manufacturer	Atmel
Part Number	AT29C257-90JC
Memory Size	Total Memory	256 Kbit (32 K x 8)
Supply Voltage (Vcc)	Operating Range	4.5 to 5.5	V
Programming Voltage	Vpp (Pin 1)	12.0	V
Standby Current	Vcc = 5.0V, Vpp = 0V	1	渭A
Active Current	Read Mode	10	mA
Programming Time	Per Byte	1.5	ms
Erase Time	Full Chip	1.5	s
Write Cycles	Endurance	100,000
Data Retention	Minimum	10	years
Operating Temperature	Industrial Range	-40 to +85	掳C
Package Type	Plastic DIP (Dual In-line Package)
Pin Count		28

Instructions for Use:

1. Power Supply:

   • Connect Vcc to the power supply (4.5V to 5.5V).
   • Connect Vpp to 12V during programming and 0V during normal operation.
   • Ground all ground pins.

2. Addressing:

   • Use the address lines (A0-A14) to select the memory location.
   • A15 is not used in this device.

3. Data I/O:

   • Data is read from or written to the memory using the data lines (D0-D7).

4. Control Signals:

   • /OE (Output Enable): Low to enable data output.
   • /WE (Write Enable): Low to write data to the memory.
   • /CE (Chip Enable): Low to select the chip.
   • /PP (Program Protect): Low to protect against accidental programming.

5. Programming:

   • Set Vpp to 12V.
   • Apply the address and data to be programmed.
   • Assert /WE low for the duration of the programming time (1.5 ms).
   • After programming, set Vpp back to 0V.

6. Erasing:

   • To erase the entire chip, apply 12V to Vpp and assert the /CE and /OE pins low.
   • Wait for the erase time (1.5 seconds).

7. Reading:

   • Set Vpp to 0V.
   • Apply the address of the memory location to be read.
   • Assert /CE and /OE low.
   • The data will be available on the data lines (D0-D7).

8. Endurance and Data Retention:

   • Ensure that the device is not subjected to more than 100,000 write cycles.
   • Data retention is guaranteed for at least 10 years under proper operating conditions.

9. Handling Precautions:

   • Handle the device with care to avoid static damage.
   • Store in a dry environment to prevent moisture damage.

For detailed specifications and advanced operations, refer to the datasheet provided by Atmel.

(For reference only)