A D V A N C E I N F O R M A T I O N
GENERAL DESCRIPTION
The Am29SL400D is an 4Mbit, 1.8 V volt-only Flash
memory organized as 524,288 bytes or 262,144 words.
The device is offered in a 48-ball FBGA package. 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 and erased in-system
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.
with a single 1.8 volt V supply. No V is required for
write or erase operations. The device can also be pro-
grammed in standard EPROM programmers.
CC
PP
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 standard device offers access times of 90, 100,
and 120 ns, 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.
Hardware data protection measures include a low
V
detector that automatically inhibits write opera-
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tions 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 in-system or via pro-
gramming equipment.
The device requires only a single 1.8 volt power
supply for both read and write functions. Internally
generated 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. Com-
mands are written to the command register using stan-
dard microprocessor write timings. Register contents
serve as input to an internal state-machine that con-
trols 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 microprocessor
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 reduced 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
simultaneously via Fowler-Nordheim tunneling. The
data is programmed using hot electron injection.
Device erasure occurs by executing the erase
command sequence. This initiates the Embedded
Erase algorithm—an internal algorithm that automati-
cally preprograms the array (if it is not already pro-
grammed) before executing the erase operation.
During erase, the device automatically times the erase
pulse widths and verifies proper cell margin.
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Am29SL400D
Rev. A Amend. +1 April 13, 2005
AMD [ AMD ]
