4 Megabit (512 K x 8-Bit)
CMOS 5.0 Volt-only, Uniform Sector Flash Memory
DISTINCTIVE CHARACTERISTICS
■ 5.0 V ± 10% for read and write operations
— Minimizes system level power requirements
■ Manufactured on 0.32 µm process technology
— Compatible with 0.5 µm Am29F040 device
■ High performance
— Access times as fast as 55 ns
■ Low power consumption
— 20 mA typical active read current
— 30 mA typical program/erase current
— 1 µA typical standby current (standard access
time to active mode)
■ Embedded Algorithms
— Embedded Erase algorithm automatically
preprograms and erases the entire chip or any
combination of designated sectors
— Embedded Program algorithm automatically
writes and verifies bytes at specified addresses
■ Minimum 1,000,000 program/er ase cycles per
sector guaranteed
■ 20-year data retention at 125°C
— Reliable operation for the life of the system
■ Package options
— 32-pin PLCC, TSOP, or PDIP
■ Flexible sector arc hitecture
— 8 uniform sectors of 64 Kbytes each
— Any combination of sectors can be erased
— Supports full chip erase
— Sector protection:
A hardware method of locking sectors to prevent
any program or erase operations within that sector
■ Compatible with JEDEC standards
— Pinout and software compatible with
single-power-supply Flash standard
— Superior inadvertent write protection
■ Data# Polling and toggle bits
— Provides a software method of detecting
program or erase cycle completion
■ 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
This Data Sheet states AMD’s current technical specifications regarding the Products described herein. This Data
Sheet may be revised by subsequent versions or modifications due to changes in technical specifications.
Publication# 21445 Rev: E Amendment/0
Issue Date: November 29, 2000
GENERAL DESCRIPTION
The Am29F040B is a 4 Mbit, 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 flexible erase capability. The 8 bits of
data appear on DQ0–DQ7. The Am29F040B is offered
in 32-pin PLCC, TSOP, and PDIP packages. This device
is designed to be programmed in-system w ith the standard system 5.0 volt V
required for write or erase operations. The device can
also be programmed in standard EPROM programmers.
This device is manufactured using AMD’ s 0. 32 µm process techno logy, and offers all the features and
benefits of the Am29F040, which was manufactured
using 0.5 µm process technology. In addtion, the
Am29F040B has a second toggle bit, DQ2, and also offers the ability to progr am in the Er ase Suspend mode .
The standard Am29F040B o ffers access times of 55,
70, 90, 120, and 150 ns, allowing high-s peed microprocessors to operate without w ait 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 v o lt po wer sup-ply 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 regis ter using
standard micropr ocessor wri te timings. Register co ntents serve as input to an internal state-machine that
controls the erase and programming ci rcuitry. Write cycles also internally latch add resses 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 executing the program
command sequence. This initiates the EmbeddedProgram algorithm—an internal algorithm that auto-
supply. A 12.0 volt VPP is not
CC
matically times the program pulse widths an d verifies
proper cell margin.
Device erasure occurs by executing the erase command sequenc e. This initiates the Embedded Erase
algorithm—an in ternal algorithm that auto matically
preprograms the arra y (if it is not already progr ammed)
before e xecuting the er ase 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 de vice is ready
to read array data or accept another command.
The sector erase ar chitecture allo ws memo ry secto rs
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
detector that automatically in hibits write opera-
V
CC
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 achie v ed via prog ramming equipment.
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 system can place the devic e into the standb y mode.
Power consumption is greatly reduced in this mode.
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 bi ts within a
sector simultaneously via Fowler-Nordheim tunneling.
The data is programmed using hot electron injection.
DQ0–DQ7 =Data Input/Output
CE#=Chip Enable
WE#=Write Enable
OE#=Output Enable
V
SS
= +5.0 V single power supply
V
CC
=Device Ground
(see Product Selector Guide for
device speed ratings and voltage
supply tolerances)
19
A0–A18
CE#
OE#
WE#
8
DQ0–DQ7
6Am29F040B
ORDERING INFORMATION
Standard Pr od ucts
AMD standard products are available in several packages and operating ranges. The order number (Valid Combination) is formed
by a combination of the following:
Am29F040B-55EC
DEVICE NUMBER/DESCRIPTION
Am29F040B
4 Megabit (512 K x 8-Bit) CMOS 5.0 Volt-only Sector Erase Flash Memory
Valid Combinations list configurations planned to be supported in volume for this device. Consult the local AMD sales
office to confirm availability of specific valid combinations and
to check on newly released combinations.
Am29F040B7
DEVICE BUS OPERATIONS
This section describes the requirements and use of the
device bus operations, which are initiated through the
internal c ommand register. The command register itself does not occupy any addressable memory
location. The register is composed of latches th at store
the commands, along with the address and data infor-
Table 1. Am29F040B Device Bus Operations
OperationCE#OE#WE#A0–A20DQ0–DQ7
mation needed to execute the command. The contents
of the register serve as inputs to the internal state machine. The state machine outputs dictate the function of
the device. The appropriate device bus operations
table lists the inputs and control le vels requ ired, and the
resulting output. The following subsections describe
each of these operations in further detail.
Note: See the “Sector Protection/Unprotection” section. for more information.
Requirements for Reading Array Data
To read array data from the outputs, the system must
drive the CE# and OE# pins to V
control and selects the device. OE# is the output control and gates arra y data to the output pins . WE# should
remain at V
The internal state machine is set for reading arr ay data
upon device power-up, or after a hardware reset. This
ensures that no spurious alteration of the memory content occurs during the power transition. No command is
necessary in this mode to obtain array data. Standard
microprocessor read cycles that assert valid addresses
on the device address input s produc e valid data on the
device data outputs. The device remains enabled for
read access until the command register contents are
altered.
See “Reading Array Data” for more information. Refer
to the AC Read Operations table for timing specifications and to the Read Operations Timings diagram for
the timing waveforms. I
table represents the active current specification for
reading array data.
, H = Logic High = VIH, VID = 12.0 ± 0.5 V, X = Don’t Care, DIN = Data In, D
IL
indicate the address space that each sector occupies.
A “sector address” consists of the address bits required
. CE# is the power
IL
to uniquely select a sector. See the “Command Definitions” section for details on erasing a sector or the
entire chip, or suspending/resuming the erase
.
IH
operation.
After the system writes the autoselect command se-
quence, the device enters the autoselect mode. The
system can then read autoselect codes from the internal register (which is separate from the memory array)
on DQ7–DQ0. Standard read cycle timings apply in this
mode. Refer to the “Autoselect Mode” and “Autoselect
Command Sequence” sections for more information.
I
in the DC Characteristics table represents the ac-
CC2
tive current specification for the write mode. The “AC
Characteristics” section contains timing specification
tables and timing diagrams for write operations.
Program and Erase Operation Status
in the DC Characteristics
CC1
During an erase or program operation, the system ma y
check the status of the operation by reading the status
bits on DQ7–DQ0. Standard read cycle timings and I
IN
IN
= Data Out, AIN = Address In
OUT
D
OUT
D
IN
read specifica tions apply. Refer to “Write Ope ration
Writing Commands/Command Sequences
To wr ite a command or command sequence (which includes programming data to the device and erasing
sectors of memory), the system must drive WE# and
CE# to V
An erase operation can erase one sect or, multiple sectors, or the entire device. The Sector Address Tables
, and OE# to VIH.
IL
Status” for more information, and to each AC Characteristics section for timing diagrams.
Standby Mode
When the system is not reading or writing to the device ,
it can place the device in the standby mode. In this
mode, current consumption is gr eatly reduced, and the
CC
8Am29F040B
outputs are placed in the high impedance state, independent of the OE# input.
The device enters the CMOS standby mode when the
0.5 V. (Note that this is a more
CE# pin is held at V
restricted voltage rang e than V
the TTL standby mode when CE# is held at V
device requires the standard ac cess time (t
CC
±
.) The device enters
IH
IH
) before it
CE
. The
is ready to read data.
If the device is deselected during erasure or programming, the device draws active current until the
operation is completed.
I
in the DC Characteristics tables represents the
CC3
standby current specification.
Output Disable Mode
When the OE# input is at VIH, output from the device is
disabled. The output pins are placed in t he high impedance state.
The autoselect mode provides manufacturer and device identification, and sector protection verification,
through identifier codes output on DQ7–DQ0. This
mode is primarily intended for progr amming equipment
to automatically match a device to be progr ammed with
its correspondi ng programming al gorithm. However,
the autoselect codes can also be accessed in-system
through the command register.
When using programming equipment, the autoselect
mode requires V
A9. Address pins A6, A1, and A0 must be as shown in
Autoselect Codes (High Voltage Method) table. In addition, when verifying sector protection, the sector
DescriptionA18–A16A15–A10A9A8–A7A6A5–A2A1A0
(11.5 V to 12.5 V) on address pin
ID
Table 3. Am29F040B Autoselect Codes (High Voltage Method)
address must appear on the appropriate highest order
address bits. Refer to the corresponding Sector Address Tables. The Command Definitio ns table shows
the remaining address bits that are don’t c are. When all
necessary bits have been set as required, the programming equipment may then read the corresponding
identifier code on DQ7–DQ0.
To access the autoselect codes in-system, the host
system can issue the autoselect command via the
command register, as shown in the Command Definitions table. This method does not require V
. See
ID
“Command Definitions” for details on using the autoselect mode.
Identifier Code on
DQ7-DQ0
Manufacturer ID: AMDXXV
Device ID: Am29F040BXXV
Sector Protection
Verification
Sector
Address
XV
ID
ID
ID
Sector Protection/Unprotection
The hardware sector protection feature disables both
program and erase operations in any sect or. The hardware sector unprotection feature re-enables both
program and erase operations in previously protected
sectors.
Sector protection/unprotection must be implemented
using programming equipment. The procedure requires a high voltage (V
) on address pin A9 and the
ID
control pins. Details on this method are provided in a
supplement, publication number 19957. Contact an
AMD representative to obtain a cop y of the appropriate
document.
The device is shipped with all sectors unprotected.
AMD offers the option of programming and protecting
sectors at its factory prior to shipping the device
through AMD’s ExpressFlash™ Servic e. Contact an
AMD representative for details.
It is possible to determine whether a sector is protected
or unprotected. See “Autoselect Mode” for details.
Hardware Data Protection
The command sequence requirement of unlock cycles
for programming or erasing provides data protection
against inadvertent writes (refer to the Command Definitions table). In addition, the following hardware data
protection measures pre vent accidental eras ure or pro-
XVILXVILV
XVILXVILV
XVILXVIHV
IL
IH
IL
01h
A4h
01h (protected)
00h (unprotected)
gramming, which might otherwise be caused by
spurious system level signals during V
power-up and
CC
power-down transitions, or from system noise.
Low V
When V
Write Inhibit
CC
is less than V
CC
, the device does not ac-
LKO
cept any write cycles. This protects data during V
power-up and power-down. The command register and
all internal program/erase circuits are disabled, and the
device resets. Subsequent writes are ignored until V
is greater than V
. The system must provide the
LKO
proper signals to the control pins to prevent unintentional writes when V
is greater than V
CC
LKO
.
Write Pulse “Glitch” Protection
Noise pulses of less than 5 ns (typical) on OE#, CE# or
WE# do not initiate a write cycle.
Logical Inhibit
Write cycles are inhibited by holding any one of OE# =
, CE# = VIH or WE# = VIH. To initiate a wr ite cycle,
V
IL
CE# and WE# must be a logical zero while OE# is a
logical one.
Power-Up Write Inhibit
If WE# = CE# = V
and OE# = VIH during power up , the
IL
device does not accept commands on the rising edge
of WE#. The internal state mac hine is automatically
reset to reading array data on power-up.
CC
CC
10Am29F040B
COMMAND DEFINITIONS
Writing specific addre ss and data commands or sequences into the command register initiates device
operations. The Command Definitions tab le defines the
valid register command sequences. Writing incorrect
address and data values or writing them in the im-
proper sequence resets the device to reading array
data.
All addresses are latched on the falling edge of WE# or
CE#, whichever happens later. All data is latched on
the rising edge of WE# or CE#, whichever happens
first. Refer to the appropriate timing diagrams in the
“AC Characteristics” section.
Reading Array Data
The device is automatically set to reading array data
after device power-up. No commands are required to
retrieve data. The device is also ready to read array
data after comp leting an Embe dded Program or Embedded Erase algorithm.
After the device accepts an Er ase Suspend command,
the device enters the Erase Suspend mode. The system can read array data using the standard read
timings, except that if it reads at an address within
erase-suspended sectors, the device outputs status
data. After completing a programming operation in the
Erase Suspend mode, the system may once again
read array data with the same exception. See “Erase
Suspend/Erase Resume Commands” for more information on this mode.
must
The system
able the dev ice f or reading arra y data if DQ5 goes high,
or while in the autoselect mode. See the “Reset Command” section, next.
See also “Requirements for Reading Arr a y Data” in the
“Device Bus Operations” section for more information.
The Read Operations table provides the read parameters, and Read Operation Timings diagram shows the
timing diagram.
issue the reset command to re-en-
Reset Command
Writing the reset command to the devi ce resets the device to reading array data. Address bits are don’t care
for this command.
The reset command may be written between the sequence cycles in an erase command sequence before
erasing begins. This resets the device to reading array
data. Once erasure begins, however, the device ignores reset commands until the operation is complete.
The reset command may be written between the sequence cycles in a program command sequence
before programming begins. This resets the device to
reading array data (also applies to programming in
Erase Suspend mode). Once programming begins,
however, the device ignores reset commands until the
operation is complete.
The reset command may be written between the sequence cycles in an autoselect command sequence.
Once in the autoselect mode, t he reset c ommand
be written to return to reading array data (also applies
to autoselect during Erase Suspend).
If DQ5 goes high during a program or erase operation,
writing the reset command returns the device to reading array data (also applies during Erase Suspend).
must
Autoselect Command Sequence
The autoselect c ommand sequenc e allows the host
system to access the manufacturer and de vices codes ,
and determine whether or not a sector is protected.
The Command Definitions table shows the address
and data requirements. This method is an a lternative to
that shown in the Autoselect Codes (High Voltage
Method) table, which is in tended for PROM programmers and requires V
The autoselect command sequence is initiated by writing two unlock cycles, followed by the autoselect
command. The device then enters the autoselect
mode, and the system may read at any address any
number of times, without initiating another command
sequence.
A read cycle at address XX00h or retrieves the manufacturer code. A read cycle at address XX01h returns
the device code. A read cycle containing a sector address (SA) and the address 02h in returns 01h if that
sector is protected, or 00h if it is unprotected. Refer to
the Sector Address tables for valid sector addresses.
The system must write the reset command to exit the
autoselect mode and return to reading array data.
on address bit A9.
ID
Byte Program Command Sequence
Programming is a four-bus-cycle operation. The program command sequence is initiated by writing two
unlock write cycles, followed by the program set-up
command. The program address and data are written
next, which in turn initiate the Embedded Program al-
not
gorithm. The system is
controls or timings. The device automatically provides
internally generated program pulses and v erify the programmed cell margin. The Command Definitions take
shows the address and data requirements for the byte
program command sequence.
When the Embedded Program algorithm is complete,
the device then returns to reading array data and addresses are no longer latched. The system can
determine the status of the program operation by using
DQ7 or DQ6. See “Write Operat ion Status ” f or inf ormation on these status bits.
required to provide further
Am29F040B11
Any commands written to the device during the Embedded Program Algorithm are ignored.
Programming is allowed in any sequence an d across
sector boundaries. A bit cannot be programmedfrom a “0” back to a “1”. Attempting to do so may halt
the operation and set DQ5 to “1”, or cause the Data#
Polling algorithm to indicate the op eration was successful. However, a succeeding read will show that the
data is still “0”. Only erase operations can convert a “0”
to a “1”.
START
Write Program
Command Sequence
Data Poll
Embedded
Program
algorithm
in progress
from System
Verify Data?
No
rithm automatically preprograms and verifies the entire
memory for an all zero data patter n prior to electr ical
erase. The system is not required to provide any controls or timings during these operations. The Command
Definitions table shows the address and data requirements for the chip erase command sequence.
Any commands written to the chip during the Embedded Erase algorithm are ignored.
The system can determine the status of the erase operation by using DQ7, DQ6, or DQ2. See “W rite
Operation Status” for information on these status bits.
When the Embedded Erase algorithm is complete, the
device returns to reading arra y data and addr esses are
no longer latched.
Figure 2 illustrates the algorithm for the erase operation. See the Erase/Program Operations tables in “AC
Characteristics” for p arameters , and to the Chip/Sector
Erase Operation Timings for t i ming waveforms.
Sector Erase Command Sequence
Sector erase is a six bus cycle operation. The sector
erase command sequence is initiated by writing two unlock cycles, followed by a set-up command. Two
additional unlock write cycles are then followed by the
address of the sector to be erased, and the sector
erase command . The Command Definitions table
shows the address and data requirements for the sector erase command sequence.
Yes
Increment Address
Note: See the appropriate Command Definitions table for
program command sequence.
No
Last Address?
Yes
Programming
Completed
Figure 1. Program Operation
Chip Erase Command Sequence
Chip erase is a six-bus-cycle operation. The chip erase
command sequence is initiated by writing two unlock
cycles, followed by a set-up command. Two additional
unlock write cycles are then followed by the chip erase
command, which in turn invokes the Embedded Erase
not
algorithm. The device does
preprogram prior to erase. The Embedded Erase algo-
require the system to
not
The device does
require the system to preprogram
the memory prior to erase. The Embedded Erase algorithm automatically programs and verifies the s ector for
an all zero data pattern prior to electrical erase. The
system is not required to provide a ny controls or timings during these operations.
After the command sequence is written, a sector erase
time-out of 50 µs begins. During the time-out period,
additional sector addresses and sector erase commands may be written. Loading the sector erase buffer
may be done in any sequence, and the number of sectors may be from one sector to all sectors. The time
between these additional cycles must be less than 50
µs, otherwise the last address and command might not
be accepted, and erasure may begin. It is recommended that processor interrupts be disabled during
this time to ensure all commands are accepted. The interrupts can be re-enabled after the last Sector Erase
command is written. If the time between additional sector erase commands can be assumed to be less than
50 µs, the system need not monitor DQ3. Any com-
mand other than Sector Erase or Erase Suspend
during the time-out period resets the device to
reading array data. The system must re write the com-
mand sequence and a ny additional sector addresses
and commands.
12Am29F040B
The system can monitor DQ3 to determine if the sector
erase timer has timed out. (See the “DQ3: Sec tor Erase
Timer” section.) The time-out be gins from the rising
edge of the final WE# pulse in the command sequence .
Once the sector erase operation has begun, onl y the
Erase Suspend command is valid. All other commands
are ignored.
When the Embedded Erase algorithm is complete, the
device returns to reading arra y data and addresses are
no longer latched. The system can determine the status of the erase operation b y usi ng DQ7, DQ6, or DQ2.
Refer to “Write Operation Status” for information on
these status bits.
Figure 2 illustrates the algorithm for the erase operation. Refer to the Erase/Program Operations tables in
the “AC Characteristics” section f or par amet ers , and to
the Sector Erase Operations Ti ming diagr am for timing
waveforms.
Erase Suspend/Erase Resume Commands
The Erase Suspend command allows the s yst em to interrupt a sector erase operation and then read data
from, or program data to, any sector not selected for
erasure. This command is valid only during the sector
erase operation, including the 50 µs time-out period
during the sector erase command sequence. The
Erase Suspend comm and is ignored if written dur ing
the chip erase operation or Embedded Program algorithm. Writing the Erase Suspend command during the
Sector Erase time-out immediately terminates the
time-out period and suspends the er ase oper at ion. Addresses are “don’t-cares” when writing the Erase
Suspend command.
When the Erase Suspend command is written during a
sector erase operation, the de vice requires a maximum
of 20 µs to suspend the erase operation. However,
when the Erase Suspend command is written during
the sector erase time-out, the device immediately terminates the time-out period and suspends the erase
operation.
After the erase operation has been suspended, the
system can read array data from or program data to
any sector not selected for erasure . (The devi ce “erase
suspends” all sectors selected for erasure.) Normal
read and write timings and command definitions apply.
Reading at any address within erase-suspended sectors produces status data on DQ7–DQ0. The system
can use DQ7, or DQ6 and DQ2 together, to determine
if a sector is actively erasing or is erase-suspended.
See “Write Operation Status” for information on these
status bits.
After an erase-suspended program operation is complete, the system can once again read arra y data within
non-suspended sectors. The system can determine
the status of the program operation using the DQ7 or
DQ6 status bits, just as in the standard program operation. See “Write Operation Status” for more
information.
The system may also write the autoselect command
sequence when the device is in the Erase Suspend
mode. The device allows reading autoselect codes
even at addresses within erasing sectors, since the
codes are not stored in the memory array. When the
device exits the autoselect mode, the device reverts to
the Erase Suspend mode, and is ready for another
valid operation. See “Autoselect Command Sequence”
for more information.
The system must write the Erase Resume command
(address bits are “don’t care”) to exit the erase suspend
mode and continue the sector erase operati on. Further
writes of the Resume command are ignored. Another
Erase Suspend command can be written after the device has resumed erasing.
START
Write Erase
Command Sequence
Data Poll
from System
No
Notes:
1. See the appropriate Command Definitions table for erase
command sequence.
2. See “DQ3: Sector Erase Timer” for more information.
X = Don’t care
RA = Address of the memory location to be read.
RD = Data read from location RA during read operation.
PA = Address of the memory location to be programmed.
Addresses latch on the falling edge of the WE# or CE# pulse,
whichever happens later.
Device ID4555AA2AA5555590X01A4
Sector Protect Verify
(Note 8)
FirstSecond Third Fourth Fifth Sixth
Addr Data Addr DataAddrData Addr Data Addr Data Addr Data
Cycles
00
4555AA2AA5555590
PD = Data to be programmed at location PA. Data latches on the
rising edge of WE# or CE# pulse, whichever happens first.
SA = Address of the sector to be verified (in autoselect mode) or
erased. Address bits A18–A16 select a unique sector.
SA
X02
01
Notes:
1. See Table 1 for description of bus operations.
2. All values are in hexadecimal.
3. Except when reading array or autoselect data, all bus cycles
are write operations.
4. Address bits A18–A11 are don’t cares for unlock and
command cycles, unless SA or PA required.
5. No unlock or command cycles required when reading array data.
6. The Reset command is required to return to reading array
data when device is in the autoselect mode, or if DQ5 goes
high (while the device is providing status da ta).
7. The fourth cycle of the autoselect command sequence is a
read cycle.
8. The data is 00h for an unprotected sector and 01h for a
protected sector.See “Autoselect Command Sequence” for
more information.
9. The system may read and program in non-erasing sectors, or
enter the autoselect mode, when in the Erase Suspend
mode. The Erase Suspend command is valid only during a
sector erase operation.
10. The Erase Resume command is valid only during the Erase
Suspend mode.
14Am29F040B
WRITE OPERATION STATUS
The device provides several bits to determine the status of a write operation: DQ2, DQ3, DQ5, DQ6, and
DQ7. Table 5 and the following subsections describe
the functions of these bits. DQ7 and DQ6 each offer a
method for determining whether a program or erase
operation is complete or in progress. These three bits
are discussed first.
DQ7: Data# Polling
The Data# Polling bit, DQ7, indicates to the host system whether an Embedded Algorithm is in progress or
completed, or whether the devic e is in Er as e Suspend.
Data# Polling is valid after the rising edge of the final
WE# pulse in the program or erase command
sequence.
rithms) figure in the “AC Characteristics” section
illustrates this.
Ta ble 5 shows the outputs for Data# Polling on DQ7.
Figure 3 shows the Data# Polling algorithm.
START
Read DQ7–DQ0
Addr = VA
During the Em bedded Program algor ithm, the device
outputs on DQ7 the complement of the datum programmed to DQ7. Thi s DQ7 status also appl ies to
programming during Erase Suspend. When the Embedded Program algorithm is complete, the device
outputs the datum programmed to DQ7. The system
must provide the program address to read valid status
information on DQ7. If a program address f alls within a
protected sector, Data# Polling on DQ7 is activ e for approximately 2 µs, then the device returns to reading
array data.
During the Embedded Erase algorithm, Data# Polling
produces a “0” on DQ7. When the Embedded Erase algorithm is complete, or if the device enters the Erase
Suspend mode, Data# Polling produces a “1” on DQ7.
This is analogous to the complement/true datum output
described for the Embedded Program algorithm: the
erase function changes all the bits in a sector to “1”;
prior to this, the device outputs the “complement,” o r
“0.” The system must provide an address within any of
the sectors selected for erasure to read valid status information on DQ7.
After an erase command sequence is written, if all s ectors selected for erasing are protected, Data# Polling
on DQ7 is active f or appro ximately 100 µs , the n the device returns to reading array data. If not all selected
sectors are protected, the Embedded Erase algorithm
erases the unprotected sectors, and ignores the selected sectors that are protected.
When the system detects DQ7 has changed from the
complement to true data, it can read valid data at
DQ7–DQ0 on the
following
read cycles. This is because DQ7 may change asynchronously with
DQ0–DQ6 while Output Enable (OE#) is asserted low.
The Data# Polling Timings (During Embedded Algo-
DQ7 = Data?
No
No
Notes:
1. VA = Valid address for programming. During a sector
erase operation, a valid address is an address within any
sector selected for erasure. During chip erase, a valid
address is any non-protected sector address.
2. DQ7 should be rechecked even if DQ5 = “1” because
DQ7 may change simultaneously with DQ5.
DQ5 = 1?
Yes
Read DQ7–DQ0
Addr = VA
DQ7 = Data?
No
FAIL
Yes
Yes
PASS
Figure 3. Data# Polling Algorithm
Am29F040B15
DQ6: Toggle Bit I
To ggle Bit I on DQ6 indi cates whether an Embe dded
Program or Erase algorithm is in progress or complete,
or whether the device has entered the Erase Suspend
mode. Toggle Bit I may be read at any address, and is
valid after the rising edge of the final WE# pulse in the
command sequence (prior to the program or eras e operation), and during the sector erase time-out.
During an Embedded Program or Erase algorithm operation, successive read cycles to any address cause
DQ6 to toggle. (The system may use either OE# or
CE# to control the read cycles.) When the operation is
complete, DQ6 stops toggling.
After an erase command sequence is written, if all s ectors selected for eras ing are protected , DQ6 toggles for
approximately 100 µs, then returns to readi ng array
data. If not all selected sectors are protected, the Embedded Erase algorithm erases the unprotected
sectors, and ignores the selected sectors that are
protected.
The system can use DQ6 and DQ2 together to determine whether a sector is actively erasing or is erasesuspended. When the device is activ ely erasing (that is ,
the Embedded Erase algorithm is in progress), DQ6
toggles. When the device enters the Erase Suspend
mode, DQ6 stops toggling. However, the system must
also use DQ2 to determine which sectors are erasing
or erase-suspended. Alternatively, the system can use
DQ7 (see the subsection on “DQ7: Data# Polling”).
If a program address falls within a pro tected sector,
DQ6 toggles for approximately 2 µs after the program
command sequence is written, then returns to reading
array data.
DQ6 also toggles during the erase-suspend-program
mode, and stops toggling once the Embedded Program algorithm is complete.
The Write Operation Status table shows the outputs for
Toggle Bit I on DQ6. Refer to Figure 4 for the toggle bit
algorithm, and to the Toggle Bit Timings figure in the
“AC Characteristics” section for the timing diagram.
The DQ2 vs. DQ6 figure shows the differences between DQ2 and DQ6 in graphical form. See also the
subsection on “DQ2: Toggle Bit II”.
DQ2: Toggle Bit II
The “Toggle Bit II” on DQ2, when used with DQ6, indicates whether a par ticular sect or is actively erasing
(that is, the Embedded Er ase alg orithm is in pr og ress),
or whether that sector is erase-suspended. Toggle Bit
II is valid after the rising edge of the final WE# pulse in
the command sequence.
DQ2 toggles when the syste m reads at addresses
within those sectors that have been selected for era-
sure. (The system may use either OE# or CE# to
control the read cycles.) But DQ2 cannot distinguish
whether the sector is actively erasing or is erase-suspended. DQ6, by comparison, indicates whether the
device is actively erasing, or is in Erase Suspend, but
cannot distinguish which sectors are selected for erasure. Thus, both status bits are required for sector and
mode information. Refer to Table 5 to compare outputs
for DQ2 and DQ6.
Figure 4 shows the toggle bit algorithm in flowchar t
form, and the section “DQ2: Toggle Bit II” explains the
algorithm. See also the “DQ6: Toggle Bit I” subsection.
Refer to the Toggle Bit Timings figure for the toggle bit
timing diagram. The DQ2 vs. DQ6 figure shows t he differences between DQ2 and DQ6 in graphical f orm.
Reading Toggle Bits DQ6/DQ2
Refer to Figure 4 for the following discussion. Whe never the system initially begins readin g toggle bit
status, it must read DQ7–DQ0 at least t wice in a row to
determine whether a toggle bit is toggling. Typically, a
system would note and store the value of the t oggle bit
after the first read. After the second read, the system
would compare the new value of the toggle bit with the
first. If the toggle bit is not toggling, the device has completed the program or eras e operation. The system can
read array data on DQ7–DQ0 o n the following read
cycle.
However, if after the initial two read cycles, the system
determines that the toggle bit is still toggling, the system also should note whether the value of DQ5 is high
(see the section on DQ5). If it is, the system should
then determine again whether the toggle bit is toggling,
since the toggle bit may have stopped toggling just as
DQ5 went high. If the toggle bit is no longer toggling,
the device has successfully completed the program or
erase operation. If it is still toggling, the device did not
complete the operation successfully, and the system
must write the reset command to return to readi ng
array data.
The remaining scenario is that the system initially determines that the toggle bit is toggling and DQ5 has not
gone high. The system may continue to monitor the
toggle bit and DQ5 through successi ve read cycles , determining the status as described in the previous
paragraph. Alternatively, it may choose to perform
other system tasks. In this cas e, the system must start
at the beginning of the algorithm when it returns to determine the status of the operation (top of Figure 4).
DQ5: Exceeded Timing Limits
DQ5 indicates whether the program or erase time has
exceeded a specified internal pulse count limit. Under
these conditions DQ5 produces a “1.” This is a failure
condition that indicates the pro gram or er ase cycle w as
not successfully completed.
16Am29F040B
The DQ5 failure condition may appear if the system
tries to program a “1” to a location that i s previously programmed to “0.” Only an era se operation can change
a “0” back to a “1.” Under this condition, the device
halts the operation, and when the operation has ex-
ceeded the timing limits, DQ5 produces a “1.”
START
Under both these conditions, t he system must issue the
reset command to return the device to reading array
data.
DQ3: Sector Erase Timer
After writing a sector erase comm and sequence, the
system may read DQ3 to determine whether or not an
erase operation has begun. (The sector erase timer
does not apply to the chip erase command.) If additional sectors are selected for erasure, the entire timeout also applies after each additional sector erase command. When the time-out is com plete, DQ3 switches
from “0” to “1.” The system may ignore DQ3 if the system can guarantee that the time between additional
sector erase commands will always be less than 50 µs.
See also the “Sector Erase Command Sequence”
section.
After the sector erase command sequence is written,
the system should read the status on DQ7 (Data# Polling) or DQ6 (Toggle Bit I) to ensure the device has
accepted the command sequence, and then read DQ3.
If DQ3 is “1”, the internally controlled erase cycle has
begun; all further commands (other than Erase Suspend) are ignored until the er ase operation is complete .
If DQ3 is “0”, the device will accept additional sector
erase commands. To ensure the command has been
accepted, the system software should ch eck the s tatus
of DQ3 prior to and following each subsequent sector
erase command. If DQ3 is high on the second status
check, the last command m ight not have been accepted. Table 5 shows the outputs for DQ3.
No
Read DQ7–DQ0
Read DQ7–DQ0
Toggle Bit
= Toggle?
Yes
DQ5 = 1?
Yes
Read DQ7–DQ0
Twice
Toggle Bit
= Toggle?
Yes
Program/Erase
Operation Not
Complete, Write
Reset Command
Note 1
No
(Notes
1, 2)
No
Program/Erase
Operation Complete
Notes:
1. Read toggle bit twice to determine whether or not it is
toggling. See text.
2. Recheck toggle bit because it may stop toggling as DQ5
changes to “1”. See text.
Figure 4. Toggle Bit Algorithm
Am29F040B17
Table 5. Write Operation Status
DQ7
Standard
Mode
Erase
Suspend
Mode
Operation
Embedded Program AlgorithmDQ7#Toggle0N/ANo toggle
Embedded Erase Algorithm0Toggle01Toggle
Reading within Erase
with Power Applied. . . . . . . . . . . . . . –55°C to +125°C
Voltage with Respect to Ground
(Note 1) . . . . . . . . . . . . . . . . .–2.0 V to 7.0 V
V
CC
A9, OE# (Note 2). . . . . . . . . . . . .–2.0 V to 12.5 V
All other pins (Note 1) . . . . . . . . . .–2.0 V to 7.0 V
Output Short Circuit Current (Note 3) . . . . . . 200 mA
Notes:
1. Minimum DC voltage on input or I/O pins is –0.5 V. During
voltage transitions, inputs may unde rshoot V
for periods of up to 20 ns. See Figure 5. Maximum DC
voltage on input and I/O pins is V
voltage transitions, input and I/O pins may overshoot to
+ 2.0 V for periods up to 20 ns. See Figure 6.
V
CC
2. Minimum DC input voltage on A9 pin is –0.5 V. During
voltage transitions, A9 and OE# may unders hoot V
–2.0 V for periods of up to 20 ns. See Figure 5. Maximum
DC input voltage on A9 and OE# is 12 .5 V which may
overshoot to 13.5 V for periods up to 20 ns.
3. No more than one output shorted to ground at a time.
Duration of the short circuit should not be greater than
one second.
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device. This is
a stress rating only; functional operation of the device at
these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure of the device to absolute maximum rating conditions for
extended periods may affect device reliability.
CC
to –2.0 V
SS
+ 0.5 V. During
to
SS
+0.8 V
–0.5 V
–2.0 V
V
CC
+2.0 V
V
CC
+0.5 V
2.0 V
20 ns
20 ns
20 ns
Figure 5. Maximum Negative
Overshoot W aveform
20 ns
20 ns
20 ns
Figure 6. Maximum Positive
Overshoot Waveform
OPERATING RANGES
Commercial (C) Devices
Ambient Temperature (T
Industrial (I) Devices
Ambient Temperature (T
Extended (E) Devices
Ambient Temperature (T
Supply Voltages
V
CC
for ± 5% devices. . . . . . . . . . .+4.75 V to +5.25 V
V
CC
for ± 10% de vices. . . . . . . . . . . .+4.5 V to +5.5 V
V
CC
Operating rang es define those limits between which the
functionality of the device is guaranteed.
) . . . . . . . . . . . 0°C to +70°C
A
) . . . . . . . . . –40°C to +85°C
A
) . . . . . . . . –55°C to +125°C
A
Am29F040B19
DC CHARACTERISTICS
TTL/NMOS Compatible
Parameter
SymbolParameter Description Test DescriptionMinTypMaxUnit
V
I
I
I
I
V
V
V
V
I
LI
LIT
I
LO
CC1
CC2
CC3
V
IL
IH
ID
OL
OH
LKO
Input Load CurrentVIN = V
A9 Input Load CurrentV
Output Leakage CurrentV
V
Active Read Current (Notes 1, 2) CE# = VIL, OE# = V
CC
VCC Active Write (Program/Erase)
Current (Notes 2, 3, 4)
CC
OUT
CE#
VCC Standby Current (Note 2)CE# = V
Input Low Level–0.50.8V
Input High Level2.0VCC + 0.5V
Voltage for Autoselect
Input Load CurrentVIN = V
A9 Input Load CurrentV
Output Leakage CurrentV
V
Active Read Current
CC
(Notes 1, 2)
V
Active Program/Erase Current
CC
(Notes 2, 3, 4)
V
Standby Current (Notes 2, 5)CE# = V
CC
Input Low Level–0.50.8V
IL
Input High Level0.7 x V
IH
Voltage for Autoselect and Sector
ID
Protect
CC
OUT
CE# = V
CE#
V
CC
Output Low VoltageIOL = 12.0 mA, VCC = VCC Min0.45V
Output High VoltageIOH = –2.5 mA, V
IOH = –100 µ
Low V
Lock-out Voltage3.24.2V
CC
to VCC, V
SS
= V
Max, A9 = 12.5 V50µA
CC
= V
to VCC, VCC = V
SS
OE# = V
IL,
OE#
= VIL,
= VIH
± 0.5 V15µA
CC
CC
IH
= V
CC
CC
Max
Max
2030mA
3040mA
CC
VCC + 0.3V
1.0µA
±
1.0µA
±
= 5.25 V10.512.5V
= V
Min 0.85 VCC V
CC
= VCC Min VCC –0.4V
A, V
CC
CC
Notes for DC Characteristics (both tables):
1. The I
2. Maximum I
3. I
current listed includes both the DC operating current and the frequency dependent component (at 6 MHz).
CC
The frequency component typically is less than 2 mA/MHz, with OE# at V
specifications are tested with VCC = V
CC
active while Embedded Algorithm (program or erase) is in progress.
CC
CCmax
.
.
IH
4. Not 100% tested.
5. For CMOS mode only, I
= 20 µA max at extended temperatures (> +85°C).
CC3
20Am29F040B
TEST CONDITIONS
Device
Under
Test
C
L
6.2 k
5.0 V
2.7 k
Ω
Ω
Output Load1 TTL gate
Output Load Capacitance, C
(including jig capacitance)
Input Rise and Fall Times520ns
Input Pulse Levels0.0–3.00.45–2.4V
Table 6. Test Specifications
Test Condition-55All others Unit
L
30100 pF
Note: Diodes are IN3064 or equivalent
Figure 7. Test Setup
KEY TO SWITCHING WAVEFORMS
WAVEFORMINPUTSOUTPUTS
Don’t Care, Any Change PermittedChanging, State Unknown
Does Not ApplyCenter Line is High Impedance State (High Z)
Input timing measurement
reference levels
Output timing measurement
reference levels
Steady
Changing from H to L
Changing from L to H
1.5 0.8, 2.0V
1.50.8, 2.0V
Am29F040B21
AC CHARACTERISTICS
Read Only Operations
Parameter Symbols
DescriptionTest Setup
t
AVAV
t
AVQV
t
ELQV
t
GLQV
t
EHQZ
t
GHQZ
t
AXQX
t
t
ACC
t
t
t
OEH
t
t
t
Read Cycle Time (Note 3)Min557090120150ns
RC
Address to Output Delay
Chip Enable to Output DelayOE# = VILMax557090120150ns
CE
Output Enable to Output DelayMax3030355055ns
OE
Output Enable Hold
Time (Note 3)
Chip Enable to Output High Z
DF
(Notes 2, 3)
Output Enable to Output High Z
DF
(Notes 2, 3)
Output Hold Time from Addresses, CE#
OH
or OE#, Whichever Occurs First
Notes:
1. See Figure 7 and Table 6 for test conditions.
2. Output driver disable time.
3. Not 100% tested.
Speed Options (Note 1)
UnitJEDECStd-55-70-90-120-150
CE# = V
OE# = V
IL,
Max557090120150ns
IL
ReadMin00000ns
Toggle and
Data# Polling
Min1010101010ns
Max1820203035ns
1820203035ns
Min00000ns
Addresses
CE#
OE#
WE#
Outputs
0 V
t
RC
Addresses Stable
t
ACC
t
OE
t
OEH
t
CE
HIGH Z
Output Valid
Figure 8. Read Operation Timings
t
OH
t
DF
HIGH Z
22Am29F040B
AC CHARACTERISTICS
Erase and Program Operations
Parameter Symbols
t
AVAV
t
AVWL
t
WLAX
t
DVWH
t
WHDX
t
GHWL
t
ELWL
t
WHEH
t
WLWH
t
WHWL
t
WHWH1
t
WHWH2
t
WC
t
AS
t
AH
t
DS
t
DH
t
OES
t
GHWL
t
CS
t
CH
t
WP
t
WPH
t
WHWH1
t
WHWH2
Speed Options
Description
UnitJEDECStd-55-70-90-120-150
Write Cycle Time (Note 1)Min557090120150ns
Address Setup TimeMin0ns
Address Hold TimeMin4045455050ns
Data Setup TimeMin2530455050ns
Data Hold TimeMin0ns
Output Enable Setup TimeMin0ns
Read Recover Time Before Write
V A = Valid address; not required for DQ6. Illustration shows first two status cycle after command sequence, last status read cycle,
and array data read cycle.
Figure 12. Toggle Bit Timings (During Embedded Algorithms)
Am29F040B25
AC CHARACTERISTICS
Enter
Embedded
Erasing
WE#
DQ6
DQ2
DQ2 and DQ6 toggle with OE# and CE#
Erase
Erase
Suspend
Erase Suspend
Suspend Program
Read
Enter Erase
Erase
Suspend
Program
Erase Suspend
Read
Erase
Resume
Erase
Erase
Complete
Note: Both DQ6 and DQ2 toggle with OE# or CE#. See the text on DQ6 and DQ2 in the section “Write Operation Status” for more
information.
Figure 13. DQ2 vs. DQ6
26Am29F040B
AC CHARACTERISTICS
Erase and Program Operations
Alternate CE# Controlled Writes
Parameter Symbols
Description
t
AVAV
t
AVEL
t
ELAX
t
DVEH
t
EHDX
t
GHEL
t
WLEL
t
EHWH
t
ELEH
t
EHEL
t
WHWH1
t
WHWH2
t
WC
t
AS
t
AH
t
DS
t
DH
t
GHEL
t
WS
t
WH
t
CP
t
CPH
t
WHWH1
t
WHWH2
Write Cycle Time (Note 1)Min557090120150ns
Address Setup TimeMin0ns
Address Hold TimeMin4045455050ns
Data Setup TimeMin2530455050ns
Data Hold TimeMin0ns
Read Recover Time Before Write Min0ns
CE# Setup TimeMin0ns
CE# Hold TimeMin0ns
Write Pulse WidthMin3035455050ns
Write Pulse Width HighMin2020202020ns
Byte Programming Operation
(Note 2)
Sector Erase Operation
(Note 2)
Typ7µs
Typ1sec
Notes:
1. Not 100% tested.
2. See the “Erase and Programming Performance” section for more information.
Speed Options
UnitJEDECStd-55-70-90-120-150
Am29F040B27
AC CHARACTERISTICS
555 for program
2AA for erase
PA for program
SA for sector erase
555 for chip erase
Data# Polling
Addresses
t
t
WC
WH
t
AS
t
AH
PA
WE#
t
GHEL
OE#
t
t
BUSY
WHWH1 or 2
DQ7#D
OUT
CE#
Data
t
CP
t
WS
t
RH
t
CPH
t
DS
t
DH
A0 for program
55 for erase
PD for program
30 for sector erase
10 for chip erase
Notes:
1. PA = Program Address, PD = Program Data, SA = Sector Address, DQ7# = Complement of Data Input, D
2. Figure indicates the last two bus cycles of the command sequence.
Excludes 00h programming prior to
erasure (Note 4)
Excludes system-level overhead
(Note 5)
Notes:
°
1. Typical program and erase times assume the following conditions: 25
C, 5.0 V VCC, 1,000,000 cycles. Additionally,
programming typicals assume checkerboard pattern.
2. Under worst case conditions of 90°C, V
= 4.5 V (4.75 V for -55), 1,000,000 cycles.
CC
3. The typical chip programming time is considerably less than the maximum chip programming time listed, since most bytes
program faster than the maximum byte program time listed. If the maximum byte program time given is exceeded, only then
does the device set DQ5 = 1. See the section on DQ5 for further information.
4. In the pre-programming step of the Embedded Erase algorithm, all bytes are programmed to 00h before erasure.
5. System-level overhead is the time required to execute the four-bus-cycle command sequence for programming. See Table 4
for further information on command definitions.
6. The device has a guaranteed minimum erase and program cycle endurance of 1,000,000 cycles.
LATCHUP CHARACTERISTICS
MinMax
Input Voltage with respect to V
Current–100 mA+100 mA
V
CC
on all I/O pins–1.0 VVCC + 1.0 V
SS
Includes all pins except VCC. Test conditions: VCC = 5.0 V, one pin at a time.