D A T A S H E E T
GENERAL DESCRIPTION
The Am29LV400B is a 4 Mbit, 3.0 volt-only Flash
memory organized as 524,288 bytes or 262,144
words. The device is offered in 48-ball FBGA, 44-pin
SO, and 48-pin TSOP packages. The word-wide data
(x16) appears on DQ15–DQ0; the byte-wide (x8) data
appears on DQ7–DQ0. This device is designed to be
programmed in-system using only a single 3.0 volt VCC
supply. No VPP is required for write or erase opera-
tions. The device can also be programmed in standard
EPROM programmers.
pre-programs 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 observing the RY/BY#
pin, or 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.
This device is manufactured using AMD’s 0.32 µm pro-
cess technology, and offers all the features and bene-
fits of the Am29LV400, which was manufactured using
0.5 µm process technology. In addition, the
Am29LV400B features unlock bypass programming
and in-system sector protection/unprotection.
The sector erase architecture allows memory sec-
tors to be erased and reprogrammed without affecting
the data contents of other sectors. The device is fully
erased when shipped from the factory.
Hardware data protection measures include a low
VCC detector that automatically inhibits write opera-
tions during power transitions. The hardware sector
protection feature disables both program and erase
operations in any combination of the sectors of mem-
ory. This can be achieved in-system or via program-
ming equipment.
The standard device offers access times of 55, 70, 90
and 120 ns, allowing high speed microprocessors to
operate without wait states. To eliminate bus conten-
tion the device has separate chip enable (CE#), write
enable (WE#) and output enable (OE#) controls.
The device requires only a single 3.0 volt power sup-
ply for both read and write functions. Internally gener-
ated and regulated voltages are provided for the
program and erase operations.
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 sector that is not selected for
erasure. True background erase can thus be achieved.
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 con-
tents 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 hardware RESET# pin terminates any operation
in progress and resets the internal state machine to
reading array data. The RESET# pin may be tied to
the system reset circuitry. A system reset would thus
also reset the device, enabling the system micropro-
cessor to read the boot-up firmware from the Flash
memory.
The device offers two power-saving features. When
addresses have been stable for a specified amount of
time, the device enters the automatic sleep mode.
The system can also place the device into the
standby mode. Power consumption is greatly re-
duced in both these modes.
Device programming occurs by executing the program
command sequence. This initiates the Embedded
Program algorithm—an internal algorithm that auto-
matically times the program pulse widths and verifies
proper cell margin. The Unlock Bypass mode facili-
tates faster programming times by requiring only two
write cycles to program data instead of four.
AMD’s Flash technology combines years of Flash
memory manufacturing experience to produce the
highest levels of quality, reliability and cost effectiveness.
The device electrically erases all bits within a sector si-
multaneously via Fowler-Nordheim tunneling. The data is
programmed using hot electron injection.
Device erasure occurs by executing the erase com-
mand sequence. This initiates the Embedded Erase
algorithm—an internal algorithm that automatically
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Am29LV400B
21523D4 December 4, 2006
SPANSION [ SPANSION ]
