FLASH MEMORY. A28F400BX-T Datasheet

A28F400BX-T MEMORY. Datasheet pdf. Equivalent

A28F400BX-T Datasheet
Recommendation A28F400BX-T Datasheet
Part A28F400BX-T
Feature A28F400BX-T; A28F400BX-T B 4-MBIT (256K x16 512K x8) BOOT BLOCK FLASH MEMORY FAMILY Automotive Y x8 x16 Input Ou.
Manufacture Intel
Download A28F400BX-T Datasheet

Intel A28F400BX-T
A28F400BX-T B
4-MBIT (256K x16 512K x8) BOOT BLOCK FLASH
Y x8 x16 Input Output Architecture
A28F400BX-T A28F400BX-B
For High Performance and High
Integration 16-bit and 32-bit CPUs
Y Optimized High Density Blocked
One 16 KB Protected Boot Block
Two 8 KB Parameter Blocks
One 96 KB Main Block
Three 128 KB Main Blocks
Top or Bottom Boot Locations
Y Extended Cycling Capability
1 000 Block Erase Cycles
Y Automated Word Byte Write and Block
Command User Interface
Status Register
Erase Suspend Capability
Y SRAM-Compatible Write Interface
Y Automatic Power Savings Feature
1 mA Typical ICC Active Current in
Static Operation
Y Very High-Performance Read
90 ns Maximum Access Time
45 ns Maximum Output Enable Time
Y Low Power Consumption
25 mA Typical Active Read Current
Y Deep Power-Down Reset Input
Acts as Reset for Boot Operations
Y Automotive Temperature Operation
b40 C to a125 C
Y Write Protection for Boot Block
Y Hardware Data Protection Feature
Erase Write Lockout During Power
Y Industry Standard Surface Mount
JEDEC ROM Compatible
44-Lead PSOP
Y 12V Word Byte Write and Block Erase
VPP e 12V g5% Standard
Y ETOXTM III Flash Technology
5V Read
Other brands and names are the property of their respective owners
Information in this document is provided in connection with Intel products Intel assumes no liability whatsoever including infringement of any patent or
copyright for sale and use of Intel products except as provided in Intel’s Terms and Conditions of Sale for such products Intel retains the right to make
changes to these specifications at any time without notice Microcomputer Products may have minor variations to this specification known as errata
November 1995
Order Number 290501-003

Intel A28F400BX-T
A28F400BX-T B
Intel’s 4-Mbit Flash Memory Family is an extension of the Boot Block Architecture which includes block-
selective erasure automated write and erase operations and standard microprocessor interface The 4-Mbit
Flash Memory Family enhances the Boot Block Architecture by adding more density and blocks x8 x16 input
output control very high speed low power an industry standard ROM compatible pinout and surface mount
packaging The 4-Mbit flash family is an easy upgrade from Intel’s 2-Mbit Boot Block Flash Memory Family
The Intel A28F400BX-T B are 16-bit wide flash memory offerings optimized to meet the rigorous environmen-
tal requirements of Automotive Applications These high density flash memories provide user selectable bus
operation for either 8-bit or 16-bit applications The A28F400BX-T and A28F400BX-B are 4 194 304-bit non-
volatile memories organized as either 524 288 bytes or 262 144 words of information They are offered in 44-
Lead plastic SOP packages The x8 x16 pinout conforms to the industry standard ROM EPROM pinout Read
and Write characteristics are guaranteed over the ambient temperature range of b40 C to a125 C
These devices use an integrated Command User Interface (CUI) and Write State Machine (WSM) for simplified
word byte write and block erasure The A28F400BX-T provide block locations compatible with Intel’s
MCS-186 family 80286 i386TM i486TM i860TM and 80960CA microprocessors The A28F400BX-B provides
compatibility with Intel’s 80960KX and 80960SX families as well as other embedded microprocessors
The boot block includes a data protection feature to protect the boot code in critical applications With a
maximum access time of 90 ns these 4-Mbit flash devices are very high performance memories which
interface at zero-wait-state to a wide range of microprocessors and microcontrollers
Manufactured on Intel’s 0 8 micron ETOXTM III process the 4-Mbit flash memory family provides world class
quality reliability and cost-effectiveness at the 4-Mbit density level

Intel A28F400BX-T
A28F400BX-T B
Throughout this datasheet the A28F400BX refers to
both the A28F400BX-T and A28F400BX-B devices
Section 1 provides an overview of the 4-Mbit flash
memory family including applications pinouts and
pin descriptions Section 2 describes in detail the
specific memory organization for the A28F400BX
Section 3 provides a description of the family’s prin-
ciples of operations Finally the family’s operating
specifications are described
1 1 Main Features
The A28F400BX boot block flash memory family is a
very high performance 4-Mbit (4 194 304 bit) memo-
ry family organized as either 256-KWords (262 144
words) of 16 bits each or 512-Kbytes (524 288
bytes) of 8 bits each
Seven Separately Erasable Blocks including a
Hardware-Lockable boot block (16 384 Bytes)
Two parameter blocks (8 192 Bytes each) and
Four main blocks (1 block of 98 304 Bytes and 3
blocks of 131 072 Bytes) are included on the 4-Mbit
family An erase operation erases one of the main
blocks in typically 3 seconds and the boot or param-
eter blocks in typically 1 5 seconds independent of
the remaining blocks Each block can be indepen-
dently erased and programmed 1 000 times
The Boot Block is located at either the top
(A28F400BX-T) or the bottom (A28F400BX-B) of the
address map in order to accommodate different mi-
croprocessor protocols for boot code location The
hardware lockable boot block provides the most
secure code storage The boot block is intended to
store the kernel code required for booting-up a sys-
tem When the RP pin is between 11 4V and 12 6V
the boot block is unlocked and program and erase
operations can be performed When the RP pin is
at or below 6 5V the boot block is locked and pro-
gram and erase operations to the boot block are
The A28F400BX products are available in the ROM
EPROM compatible pinout and housed in the
44-Lead PSOP (Plastic Small Outline) package as
shown in Figure 3
The Command User Interface (CUI) serves as the
interface between the microprocessor or microcon-
troller and the internal operation of the A28F400BX
flash memory
Program and Erase Automation allows program
and erase operations to be executed using a two-
write command sequence to the CUI The internal
Write State Machine (WSM) automatically executes
the algorithms and timings necessary for program
and erase operations including verifications there-
by unburdening the microprocessor or microcontrol-
ler Writing of memory data is performed in word or
byte increments typically within 9 ms which is a
100% improvement over previous flash memory
The Status Register (SR) indicates the status of the
WSM and whether the WSM successfully completed
the desired program or erase operation
Maximum Access Time of 90 ns (TACC) is achieved
over the automotive temperature range 10% VCC
supply range (4 5V to 5 5V) and 100 pF output load
IPP maximum Program current is 40 mA for x16
operation and 30 mA for x8 operation IPP Erase
current is 30 mA maximum VPP erase and pro-
gramming voltage is 11 4V to 12 6V (VPP e 12V
g 5%) under all operating conditions Typical
ICC Active Current of 25 mA is achieved
The 4-Mbit boot block flash memory family is also
designed with an Automatic Power Savings (APS)
feature to minimize system battery current drain and
allows for very low power designs Once the device
is accessed to read array data APS mode will imme-
diately put the memory in static mode of operation
where ICC active current is typically 1 mA until the
next read is initiated
When the CE and RP pins are at VCC and the
BYTE pin is at either VCC or GND the CMOS
Standby mode is enabled where ICC is typically
80 mA
A Deep Power-Down Mode is enabled when the
RP pin is at ground minimizing power consumption
and providing write protection during power-up con-
ditions ICC current during deep power-down mode
is 50 mA typical An initial maximum access time or
Reset Time of 300 ns is required from RP switch-
ing until outputs are valid Equivalently the device
has a maximum wake-up time of 210 ns until writes
to the Command User Interface are recognized
When RP is at ground the WSM is reset the
Status Register is cleared and the entire device is
protected from being written to This feature pre-
vents data corruption and protects the code stored
in the device during system reset The system Reset
pin can be tied to RP to reset the memory to nor-
mal read mode upon activation of the Reset pin
With on-chip program erase automation in the
4-Mbit family and the RP functionality for data pro-
tection when the CPU is reset and even if a program
or erase command is issued the device will not rec-
ognize any operation until RP returns to its normal

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