LH28F320SKTD-ZR Sharp Microelectronics, LH28F320SKTD-ZR Datasheet - Page 36

• Manufacturer Part Number: LH28F320SKTD-ZR
• Description: IC FLASH 32MBIT 70NS 48TSOP
• Manufacturer: Sharp Microelectronics

Specifications of LH28F320SKTD-ZR

• Format - Memory: FLASH
• Memory Type: FLASH
• Memory Size: 32M (4Mx8, 2Mx16)
• Speed: 70ns
• Interface: Parallel
• Voltage - Supply: 2.7 V ~ 3.6 V, 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 48-TSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 425-2463; LHF32KZR

5 DESIGN CONSIDERATIONS
5.1 Three-Line Output Control
The device will often be used in large memory arrays.
SHARP
accommodate multiple memory connections. Three-
Line control provides for:
To use these control inputs efficiently, an address
decoder should enable BE# while OE# should be
connected to all memory devices and the system’s
READ# control line. This assures that only selected
memory
deselected memory devices are in standby mode.
RP#
POWERGOOD signal to prevent unintended writes
during system power transitions. POWERGOOD
should also toggle during system reset.
5.2 STS and Block Erase, Bank Erase,
STS is an open drain output that should be
connected to V
hardware method of detecting block erase, bank
erase, (multi) word/byte write and block lock-bit
configuration
transitions low after block erase, bank erase, (multi)
word/byte
commands and returns to V
finished
alternate
Configuration command.
a. Lowest possible memory power dissipation.
b. Complete assurance that data bus contention will
not occur.
(Multi) Word/Byte Write and Block
Lock-Bit Configuration Polling
should
executing
devices
provides
STS
write or block lock-bit configuration
completion.
CC
be
by a pullup resistor to provide a
pin
have
connected
the
three
configurations,
internal
OH
active
In
control
when the WSM has
default
to
algorithm.
outputs
the
inputs
mode,
see
system
while
For
the
LHF32KZR
to
it
STS can be connected to an interrupt input of the
system CPU or controller. It is active at all times.
STS, in default mode, is also High Z when the device
is in block erase suspend (with (multi) word/byte write
inactive), (multi) word/byte write suspend or deep
power-down modes.
5.3 Power Supply Decoupling
Flash memory power switching characteristics require
careful device decoupling. System designers are
interested in three supply current issues; standby
current levels, active current levels and transient
peaks produced by falling and rising edges of BE#
and OE#. Transient current magnitudes depend on
the device outputs’ capacitive and inductive loading.
Two-line control and proper decoupling capacitor
selection will suppress transient voltage peaks. Each
device should have a 0.1µF ceramic capacitor
connected between its V
V
capacitors should be placed as close as possible to
package leads. Additionally, for every eight devices,
a 4.7µF electrolytic capacitor should be placed at the
array’s power supply connection between V
GND. The bulk capacitor will overcome voltage
slumps caused by PC board trace inductance.
5.4 V
Updating flash memories that reside in the target
system requires that the printed circuit board
designer pay attention to the V
The V
block erase, bank erase, (multi) word/byte write and
block lock-bit configuration. Use similar trace widths
and layout considerations given to the V
bus. Adequate V
decrease V
PP
and GND. These high-frequency, low inductance
PP
PP
pin supplies the memory cell current for
Trace on Printed Circuit Boards
PP
voltage spikes and overshoots.
PP
supply traces and decoupling will
CC
and GND and between its
PP
Power supply trace.
CC
CC
power
and
33