at27bv400 ATMEL Corporation, at27bv400 Datasheet - Page 2

• Manufacturer Part Number: at27bv400
• Description: 4-megabit 256k 512k Unregulated Battery-voltage High Speed Eprom
• Manufacturer: ATMEL Corporation

mode operation. The by-16 organization makes this part
ideal for portable and hand held 16- and 32-bit micropro-
cessor systems using either regulated or unregulated bat-
tery power.
Atmel’s innovative design techniques provide fast speeds
that rival 5V parts while keeping the low power consump-
tion of a 3V supply. At V
accessed in less than 120ns. With a typical power dissipa-
tion of only 10 mW at 5mHZ and V
consumes less than one fifth the power of a standard 5V
EPROM.
Standby mode supply current is typically less than 1 mA at
3V. The AT27BV400 simplifies system design and
stretches battery lifetime even further by eliminating the
need for power supply regulation.
The AT27BV400 can be organized as either word-wide or
byte-wide. The organization is selected via the BYTE/V
pin. When BYTE/V
organization is selected and the O15/A-1 pin is used for
O15 data output. When BYTE/V
byte wide organization is selected and the O15/A-1 pin is
used for the address pin A-1. When the AT27BV400 is logi-
cally regarded as x16 (word-wide), but read in the byte-
wide mode, then with A-1= V
word are selected with A-1 = V
bit word are selected.
The AT27BV400 is available in industry standard JEDEC-
approved one-time programmable (OTP) PLCC, SOIC
(SOP), and TSOP packages. The device features two-line
control(CE,OE) to eliminate bus contention.
With high density 256K word or 512K byte storage capabil-
ity, the AT27BV400 allows firmware to be to be stored reli-
ably and to be accessed by the system without the delays
of mass storage media.
The AT27BV400 operating with V
level outputs that are compatible with standard TTL logic
Block Diagram
2
PP
is asserted high (V
AT27BV400
CC
IL
the lower 8 bits of the 16-bit
IH
= 2.7V, any word can be
PP
the upper 8 bits of the 16-
CC
CC
is asserted low (V
at 3.0V produces TTL
= 3V, the AT27BV400
IH
), the word-wide
IL
),the
PP
devices operating at V
compatible with JEDEC approved low voltage battery oper-
ation (LVBO) interface specifications. The device is also
capable of standard 5-volt operation making it ideally suited
for dual supply range systems or card products that are
pluggable in both 3-volt and 5-volt hosts.
Atmel’s AT27BV400 has additional features that ensure
high quality and efficient production use. The Rapid
gramming Algorithm reduces the time required to program
the part and guarantees reliable programming. Program-
ming time is typically only 50 s/word. The Integrated Prod-
uct Identification Code electronically identifies the device
and manufacturer. This feature is used by industry standard
programming equipment to select the proper programming
equipment and voltages. The AT27BV400 programs
exactly the same way as a standard 5V AT27C400 and
uses the same programming equipment.
System Considerations
Switching between active and standby conditions via the
Chip Enable pin may produce transient voltage excursions.
Unless accommodated by the system design, these tran-
sients may exceed data sheet limits, resulting in device
non-conformance. At a minimum, a 0.1 F high frequency,
low inherent inductance, ceramic capacitor should be uti-
lized for each device. This capacitor should be connected
between the V
close to the device as possible. Additionally, to stabilize the
supply voltage level on printed circuit boards with large
EPROM arrays, a 4.7 F bulk electrolytic capacitor should
be utilized, again connected between the V
terminals. This capacitor should be positioned as close as
possible to the point where the power supply is connected
to the array.
CC
and Ground terminals of the device, as
CC
= 5V. At V
CC
= 2.7V, the part is
CC
and Ground
TM
Pro-