Details

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BUY AT27C256R https://www.utsource.net/itm/p/12611145.html

Parameter	Symbol	Conditions	Min	Typ	Max	Unit
Supply Voltage	VCC	Operating	2.7		5.5	V
Standby Current	ICC	VCC = 5.5V, All pins Hi-Z		1		μA
Active Current	ICC	Reading		30		mA
Output High Level Voltage	VOH	IO ≤ -1mA	2.4		VCC	V
Output Low Level Voltage	VOL	IO ≥ 1mA			0.5	V
Access Time	tACC	VCC = 5.5V		90		ns
Data Retention Time				20		Years

Instructions for AT27C256R

1. Power Supply Connection:

   • Connect the VCC pin to a power supply within the operating voltage range (2.7V to 5.5V).
   • Ensure that the GND pin is connected to ground.

2. Address and Data Lines:

   • Connect address lines A0-A17 to the appropriate address bus.
   • Connect data lines D0-D7 to the data bus for read/write operations.

3. Chip Enable (CE):

   • CE must be low for the chip to be active. When high, the device enters standby mode.

4. Output Enable (OE):

   • OE must be low during read operations. It enables the outputs when low.

5. Write Protect (WP):

   • The WP pin can be used to prevent accidental writes. Connect it to VCC to enable write protection or to GND to allow writing.

6. Reading Data:

   • To read data, set CE and OE low and provide the desired address on the address lines. Data will appear on the data lines after the access time (tACC).

7. Writing Data:

   • Writing is not directly supported by this ROM. For programming, use an external programmer designed for the AT27C256R.

8. Handling:

   • Handle with care as ESD (Electrostatic Discharge) can damage the device. Use proper anti-static precautions.

9. Storage:

   • Store in a dry environment to avoid moisture damage. Keep away from strong magnetic fields.

10. End of Life:

    • After approximately 20 years, data retention may degrade. Plan for replacement if long-term storage is required.

(For reference only)