FLASH
AS29F040
GENERAL DESCRIPTION
The AS29F040 is a 4Mbit, 5.0 Volt-only FLASH memory
organized as 524,288 Kbytes of 8 bits each. The 512 Kbytes of
data are divided into eight sectors of 64 Kbytes each for flex-
ible erase capability. The 8 bits of data appear on DQ0-DQ7.
The device is designed to be programmed in-system with the
program pulse widths and verifies proper cell margin.
Device erasure occurs by executing the erase command
sequence. This invokes 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 cell margin.
The host system can detect whether a program or erase
operation is complete by reading the DQ7 (Data\Polling) and
DQ6 (toggle) status bits. After a program or erase cycle has
been completed, the device is ready to read array data or accept
another command.
standard system 5.0 Volt VCC supply. A 12.0 volt VPP is not
required for write or erase operations. The device can also be
programmed in standard EPROM programmers.
This device is manufactured using 0.32 μm process
technology. In addition, it has a second toggle bit, DQ2, and
offers the ability to program in the Erase Suspend mode.
It is available with access times of 55, 60, ^+^+6=70, 90,
120, and 150ns, allowing high-speed microprocessors to oper-
ate 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 device is entirely 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.
The sector erase architecture allows memory sectors to be
erased and reprogrammed without affecting the data contents
of other sectors. The device is fully erased when shipped from
the factory.
The hardware data protection measures include a low
VCC detector that automatically inhibits write operations
during power transitions. The hardware sector protection
feature disables both program and erase operations in any
combination of the sectors of memory. This can be achieved
via programming equipment.
The erase suspect feature enables the user to put erase on
hold for any period of time to read data from, or program data
to, any sector that is not selected for erasure. True background
erase can thus be achieved.
The system can place the device into the standby mode.
Power consumption is greatly reduced in this mode. The
device electrically erases all bits within a sector simultaneously
via Fowler-Nordheim tunneling. The data is programmed using
hot electron injection.
Device programming occurs by executing the program
command sequence. This invokes the Embedded Program
algorithm -- an internal algorithm that automatically times the
PIN CONFIGURATION
LOGIC SYMBOL
PIN
DESCRIPTION
A0 - A18 Address Inputs
DQ0 - DQ7 Data Inputs/Outputs
CE\
OE\
WE\
Chip Enable
Output Enable
Write Enable
V
+5V Single Power Supply
Device Ground
CC
V
SS
AS29F040
Micross Components reserves the right to change products or specifications without notice.
Rev. 2.3 01/10
2
MICROSS [ MICROSS COMPONENTS ]
