Features
• Single 2.7V - 3.6V Supply
• Fast Read Access Time – 200 ns
• Automatic Page Write Operation
– Internal Address and Data Latches for 64 Bytes
– Internal Control Timer
• Fast Write Cycle Times
– Page Write Cycle Time: 10 ms Maximum
– 1- to 64-byte Page Write Operation
• Low Power Dissipation
– 15 mA Active Current
–20 µA CMOS Standby Current
• Hardware and Software Data Protection
• Data Polling for End of Write Detection
• High Reliability CMOS Technology
– Endurance: 10,000 Cycles
– Data Retention: 10 Years
• JEDEC Approved Byte-wide Pinout
• Industrial Temperature Ranges
• Green (Pb/Halide-free) Packaging Option Only
1. Description
The AT28BV256 is a high-performance electrically erasable and programmable read-
only memory. Its 256K of memory is organized as 32,768 words by 8 bits. Manufac-
tured with Atmel’s advanced nonvolatile CMOS technology, the device offers access
times to 200 ns with power dissipation of just 54 mW. When the device is deselected,
the CMOS standby current is less than 200 µA.
The AT28BV256 is accessed like a Static RAM for the read or write cycle without the
need for external components. The device contains a 64-byte page register to allow
writing of up to 64 bytes simultaneously. During a write cycle, the addresses and 1 to
64 bytes of data are internally latched, freeing the address and data bus for other
operations. Following the initiation of a write cycle, the device will automatically write
the latched data using an internal control timer. The end of a write cycle can be
detected by Data
polling of I/O7. Once the end of a write cycle has been detected a
new access for a read or write can begin.
Atmel’s AT28BV256 has additional features to ensure high quality and manufactura-
bility. The device utilizes internal error correction for extended endurance and
improved data retention characteristics. An optional software data protection mecha-
nism is available to guard against inadvertent writes. The device also includes an
extra 64 bytes of EEPROM for device identification or tracking.
256K (32K x 8)
Battery-Voltage
Parallel
EEPROMs
AT28BV256
0273K–PEEPR–2/09
