The A29040B is a 5.0 volt-only Flash memory organized as 524,288 bytes of 8 bits each. The 512 Kbytes of data are further
divided into eight sectors of 64 Kbytes each for flexible sector erase capability. The 8 bits of data appear on I/O0 -I/O7 while the addresses are input on A0 to A18. The A29040B is offered in 32-pin PLCC, TSOP, and PDIP packages. This device is designed to be programmed insystem with the standard system 5.0volt VCC supply.Additional 12.0 volt VPP is not required for in-system write or erase operations. However, the A29040B can also be programmed in standard EPROM programmers.

The A29040B has a second toggle bit, I/O2, to indicate whether the addressed sector is being selected for erase, and also offers the ability to program in the Erase Suspend mode.The standard A29040B offers access times of 55, 70 and 90ns, allowing high-speed microprocessors to operate without wait states. To eliminate bus contention the device has separate chip enable (CE ), write enable ( WE ) and output enable (OE ) controls.

The device requires only a single 5.0 volt power supply for both read and write functions. Internally generated and regulated voltages are provided for the program and erase operations.

The A29040B is entirely software command set compatible with the JEDEC single-power-supply Flash standard.Commands are written to the command register using standard microprocessor write timings. Register contents serve as input to an internal state-machine that controls the erase and programming circuitry.

Write cycles also internally latch addresses and data needed for the programming and erase operations. Reading data out of the device is similar to reading from other Flash or EPROM devices.

Device programming occurs by writing the proper program command sequence. This initiates the Embedded Program algorithm - an internal algorithm that automatically times the program pulse widths and verifies proper program margin.Device erasure occurs by executing the proper erase command sequence. This initiates the Embedded Erase algorithm - an internal algorithm that
automatically preprograms the array (if it is not already programmed)before executing the erase operation. During erase, the
device automatically times the erase pulse widths and verifies proper erase margin.

The host system can detect whether a program or erase operation is complete by reading the I/O7 (Data Polling) and I/O6 (toggle) status bits. After a program or erase cycle has been completed, the device is ready to read array data or accept another command.

The sector erase architecture allows memory sectors to be erased and reprogrammed without affecting the data contents of other sectors. The A29040B is fully erased when shipped from the factory.

The hardware sector protection feature disables operations for both program and erase in any combination of the sectors of memory. This can be achieved via programming quipment.

The Erase Suspend feature enables the user to put erase on hold for any period of time to read data from, or program data to, any other sector that is not selected for erasure.True background erase can thus be achieved.Power consumption is greatly reduced when the device is placed in the standby mode.

DC Characteristics:

? 5.0V ± 10% for read and write operations
? Access times:- 55/70/90 (max.)
? Current:
- 20 mA typical active read current
- 30 mA typical program/erase current
- 1 μA typical CMOS standby
? Flexible sector architecture
- 8 uniform sectors of 64 Kbyte each
- Any combination of sectors can be erased
- Supports full chip erase
- Sector protection:A hardware method of protecting sectors to prevent any inadvertent program or erase operations within that
sector
? Extended operating temperature range: -40°C~+85°C for -U series
? Embedded Erase Algorithms
- Embedded Erase algorithm will automatically erase the entire chip or any combination of designated sectors and verify the erased sectors
- Embedded Program algorithm automatically writes and verifies bytes at specified addresses
? Typical 100,000 program/erase cycles per sector
? 20-year data retention at 125°C
- Reliable operation for the life of the system
? Compatible with JEDEC-standards
- Pinout and software compatible with single-powersupply Flash memory standard
- Superior inadvertent write protection
? Data Polling and toggle bits
- Provides a software method of detecting completion of program or erase operations
? Erase Suspend/Erase Resume
- Suspends a sector erase operation to read data from,or program data to, a non-erasing sector, then resumes the erase operation