28F016C3 查看數據表（PDF） - Intel
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28F016C3 Datasheet PDF : 59 Pages
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3 VOLT ADVANCED+ BOOT BLOCK
E
substantially reduces power consumption. Outputs
are placed in a high-impedance state independent
of the status of the OE# signal. If CE# transitions to
a logic-high level during erase or program
operations, the device will continue to perform the
operation and consume corresponding active power
until the operation is completed.
System engineers should analyze the breakdown of
standby time versus active time and quantify the
respective power consumption in each mode for
their specific application. This will provide a more
accurate measure of application-specific power and
energy requirements.
3.6.4
DEEP POWER-DOWN MODE
The deep power-down mode is activated when
RP# = VIL (GND ± 0.2 V). During read modes, RP#
going low de-selects the memory and places the
outputs in a high impedance state. Recovery from
deep power-down requires a minimum time of tPHQV
for read operations and tPHWL/tPHEL for write
operations.
During program or erase modes, RP# transitioning
low will abort the in-progress operation. The
memory contents of the address being programmed
or the block being erased are no longer valid as the
data integrity has been compromised by the abort.
During deep power-down, all internal circuits are
switched to a low power savings mode (RP#
transitioning to VIL or turning off power to the device
clears the status register).
3.7 Power-Up/Down Operation
The device is protected against accidental block
erasure or programming during power transitions.
Power supply sequencing is not required, since the
device is indifferent as to which power supply, VPP
or VCC, powers-up first.
3.7.1
RP# CONNECTED TO SYSTEM
RESET
The use of RP# during system reset is important
with automated program/erase devices since the
system expects to read from the flash memory
when it comes out of reset. If a CPU reset occurs
without a flash memory reset, proper CPU
initialization will not occur because the flash
memory may be providing status information
instead of array data. Intel recommends connecting
RP# to the system CPU RESET# signal to allow
24
proper CPU/flash initialization following system
reset.
System designers must guard against spurious
writes when VCC voltages are above VLKO. Since
both WE# and CE# must be low for a command
write, driving either signal to VIH will inhibit writes to
the device. The CUI architecture provides additional
protection since alteration of memory contents can
only occur after successful completion of the two-
step command sequences. The device is also
disabled until RP# is brought to VIH, regardless of
the state of its control inputs. By holding the device
in reset (RP# connected to system PowerGood)
during power-up/down, invalid bus conditions during
power-up can be masked, providing yet another
level of memory protection.
3.7.2
VCC, VPP AND RP# TRANSITIONS
The CUI latches commands as issued by system
software and is not altered by VPP or CE#
transitions or WSM actions. Its default state upon
power-up, after exit from reset mode or after VCC
transitions above VLKO (Lockout voltage), is read
array mode.
After any program or block erase operation is
complete (even after VPP transitions down to
VPPLK), the CUI must be reset to read array mode
via the Read Array command if access to the flash
memory array is desired.
3.8 Power Supply Decoupling
Flash memory’s power switching characteristics
require careful device decoupling. System
designers should consider three supply current
issues:
1. Standby current levels (ICCS)
2. Read current levels (ICCR)
3. Transient peaks produced by falling and rising
edges of CE#.
Transient current magnitudes depend on the device
outputs’ capacitive and inductive loading. Two-line
control and proper decoupling capacitor selection
will suppress these transient voltage peaks. Each
flash device should have a 0.1 µF ceramic
capacitor connected between each VCC and GND,
and between its VPP and GND. These high-
frequency, inherently low-inductance capacitors
should be placed as close as possible to the
package leads.
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