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Functional Deion
Read Mode
The A278308A has two control functions， both of which
must be logically active in order to obtain data at the
outputs. CE is the power control and should be used for
device selection. OE is the output control and should
be used to data to the output pins， which is independent
of device selection. Assuming that addresses are stable，
address access time (tAA) is equal to the delay from CE
to output (tCE). Data is available at the output after a
delay (tOE) from the falling edge of OE ， as long as CE
has been low and the addresses have been stable for at
least tACC - tOE.
Standby Mode
The A278308A has a standby mode which reduces the
active current from 30mA to 100μA. The A278308A is
placed in the standby mode by applying a CMOS high
signal to CE . When in the standby mode， the output are
in a high impedance state， independent of the OE .
Absolute Maximum Ratings*
Ambient Operating Temperature (TA) . . . -10°C to +85°C
Storage Temperature Plastic Package (TSTG) . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55°C to 125°C
Applied Input Voltage (VI):
All Pins Except A9， VPP and VCC . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . .-0.6V to VCC + 0.6V
A9， VPP . . . . . . . . . . . . . . . . . . . . . . . -0.6V to 13.5V
VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.6V to 7.0V
Output Voltage (VO) . . . . . . . . . . . -0.6V to 7.0V (Note 1) |
Auto Identify Mode
The auto identify mode allows the reading out of a binary
code from a EPROM that will identify its manufacturer
and type. This mode is intended for use by programming
equipment for the purpose of automatically matching the
device to be programmed with its corresponding
programming algorithm.
To activate the mode， the programming equipment must
apply 12.0V ± 0.5V on address line A9 of the A278308A.
Three identification code can be read from data output
pin by toggling A0 and A1. The other addresses must be
held at VIL during this mode. Byte 0 (with A0 at VIL， A1 at
VIL) represents the manufacturer code which is 37H.
Byte 1 and Byte 2 represent the device code and
continuation code， which is 64H and 7FH respectively.
All identifiers for these codes will possess odd parity，
with MSB (IO7) defined the parity bit.
*Comments
Stresses above those listed under "Absolute Maximum
Ratings" may cause permanent damage to this device.
These are stress ratings only. Functional operation of
this device at these or any other conditions above those
indicated in the operational sections of this specification
is not implied or intended. Exposure to the absolute
maximum rating conditions for extended periods may
affect device reliability. |
