AT28BV256-20TU-T Microchip

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 256K (32K x 8) Low Power Dissipation 15 mA Active Current Battery-Voltage 20 A CMOS Standby Current Hardware and Software Data Protection Parallel Data Polling for End of Write Detection High Reliability CMOS Technology EEPROMs Endurance: 10,000 Cycles Data Retention: 10 Years JEDEC Approved Byte-wide Pinout AT28BV256 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 Atmels 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 A. 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. Atmels 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. 0273KPEEPR2/092.2 28-lead SOIC Top View 2. Pin Configurations Pin Name Function A14 1 28 VCC A0 - A14 Addresses A12 2 27 WE A7 3 26 A13 CE Chip Enable A6 4 25 A8 A5 5 24 A9 OE Output Enable A4 6 23 A11 Write Enable WE A3 7 22 OE A2 8 21 A10 I/O0 - I/O7 Data Inputs/Outputs A1 9 20 CE NC No Connect A0 10 19 I/O7 I/O0 11 18 I/O6 DC Dont Connect I/O1 12 17 I/O5 I/O2 13 16 I/O4 GND 14 15 I/O3 2.1 32-lead PLCC Top View 2.3 28-lead TSOP Top View OE 1 28 A10 A11 2 27 CE A9 3 26 I/O7 A6 5 29 A8 A8 4 25 I/O6 A5 6 28 A9 A13 5 24 I/O5 WE 6 23 I/O4 A4 7 27 A11 VCC 7 22 I/O3 A3 8 26 NC A14 8 21 GND A2 9 25 OE A12 9 20 I/O2 A1 10 24 A10 A7 10 19 I/O1 A0 11 23 CE A6 11 18 I/O0 A5 12 17 A0 NC 12 22 I/O7 A4 13 16 A1 I/O0 13 21 I/O6 A3 14 15 A2 Note: 1. PLCC package pins 1 and 17 are Dont Connect. 2 AT28BV256 0273KPEEPR2/09 I/O1 14 4 A7 I/O2 15 3 A12 GND 16 2 A14 DC 17 1 DC I/O3 18 32 VCC I/O4 19 31 WE I/O5 20 30 A13