The AT27C800 is a low-power, high performance 8,388,608-bit UV erasable programmable read only memory (EPROM) organized as either 512K by 16 or 1024K by 8
bits. It requires a single 5 V power supply in normal r ead mode oper ation. Any word
can be accessed in less than 100 ns, eliminating the need for speed-reducing WAIT
states. The x16 organization makes this part ideal for high-performance 16- and 32-bit
microprocessor systems.
(continued)
AT27C800
8-Megabit
(512K x 16 or
1024K x 8)
UV Erasable
EPROM
The AT27C800 can be organized as either word-wide or
µ
µ
µ
µ
µ
byte-wide. The organi zation is selected via the BYTE
/V
PP
pin. When BYTE/VPP is asserted high (VIH), the word-wide
organization is selected and the O15/A-1 pin is used for
O15 data output. When BYT E
/VPP is asserted low (VIL),the
byte wide organization is se lected and the O 15/A-1 pin is
used for the address pin A-1. When the AT27C800 is logically regarded as x 16 (word-wide), but read in the bytewide mode, then with A-1=V
bit word are selected with A-1 =V
the lower eight bits of the 16
IL
the upper 8 bits of the
IH
16-bit word are selected.
In read mode, the AT27C800 typically consumes 15 mA.
Standby mode supply current is typically less than 10
A.
The AT27C800 is available in industry standard JEDECapproved one-time program mable (OTP)PDIP, SOIC
(SOP), and TSOP as well as UV erasable windowed Cerdip packages. The device features two-line contro l(CE
,OE)
to eliminate bus contention in high-speed systems.
With high den sity 51 2K word o r 1 024K -bit stora ge c apab il-
ity, the AT27C800 allo ws firm ware to b e to be st ored reliably and to be accessed by the system without the delays
of mass storage media.
Atmel’s AT27C800 has additional features that ensure high
quality and effici ent pr oducti on us e. The Rapid
TM
Programming Algorithm reduces the time required to program the
part and guarantees reliable programming. Programming
time is typically only 50
s/word. The Integrated Product
Identification Code elect ronically i dentifies th e device and
manufacturer. This feature is used by industry standard
programming equi pmen t to sele ct t he prop er progr ammi ng
equipment and voltages.
Erasure Characteristics
The entire memory array of the AT27C8 00 is erased (all
outputs re ad as V
) after exposure to ultraviolet light at a
OH
wavelength of 2,537Å. Complete erasure i s as su red after a
minimum of 20 minutes of exposure using 12,000
W/cm
intensity lamps spaced one inch away from the chip. Minimum erase time for lamps a t other intensi ty rating s can be
calculated from the minimum integrated erasure dose of 15
W.sec/cm
2
. To prevent unintentional erasure, an opaque
label is recommended to cover the clear window on any UV
erasable EPROM that will be subjected to co ntinuous
flourescent indoor lighting or sunlight.
System Considerations
Switching between active and standby conditions via the
Chip Enable pin may produce tran sient voltage excursions.
Unless accommodated by the system design, these transients may exceed data sheet limits, resulting in device
non-conformance. At a minimum, a 0.1
low inherent inductance, ceramic capacitor should be utilized for each device. This capacitor should be connec ted
between the V
and Ground terminals of the device, as
CC
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.
F high frequency,
and Ground
CC
2
Block Diagram
2
AT27C800
Absolute Maximum Ratings*
AT27C800
Temperature Under Bias...................-55 ° C to +125°C
*NOTICE:Stresses beyond those listed under “Absolute
Maximum Ratings” may cause permanent dam-
Storage Temperature ........................-65 ° C to +150°C
age to the device . This is a stress rating only and
functional oper atio n of the device at the se o r any
Voltage on Any Pin with
with Respect to Ground.....................-2.0V to +7.0V
Voltage on A9 with
Respect to Ground .........................-2.0V to +14.0V
VPP Supply Voltage with
Respect to Ground ..........................-2.0V to +14.0V
Integrated UV Erase Dose............... 7258 W •sec/cm
(1)
(1)
Note:1.Minimum voltage is -0.6V DC which may under-
(1)
2
other conditions beyond those indicated in the
operational sections of this specification is not
implied. Exposure to absolute maximum rating
conditions f or extende d periods may aff ect de vice
reliability .
shoot to -2.0V for pulses of less than 20 ns. Maximum output pin voltag e is Vcc + 0.75V DC which
may overshoot to + 7.0V for pulses of less than
20 ns.
0706050403020100
Manufacturer0000111101E1E
Device Type 111111000F8F8
Hex Data
8
AT27C800
Rapid Programming Algorithm
µ
µ
A 50 µs CE pulse width is used to program. The address is
set to the first location. V
is raised to 13.0V. Each address is first pr ogrammed with
one 50
reprogramming loop is executed for each address. In the
event a word fails to pass verification, up to 10 successive
50
pulse. If the word fails to verify after 10 pulses have been
applied, the part is considered failed. After the word verifies
properly, the next address is selected until all have been
checked. V
words are read again and compared with the original data
to determine if the device passes or fails.
s CE pulse without verification. Then a verification/
s pulses are applied with a verification after each