LH540235M-20 SHARP [Sharp Electrionic Components], LH540235M-20 Datasheet - Page 36

• Manufacturer Part Number: LH540235M-20
• Description: 2048 x 18 / 4096 x 18 Synchronous FIFOs
• Manufacturer: SHARP [Sharp Electrionic Components]

TIMING DIAGRAMS (cont’d)
LH540235/45
APPLICATIONS INFORMATION
Standalone Configuration
application, the LH540235/45 is placed in standalone
mode by tying the two Expansion In pins WXI/ WEN
RXI/ REN
Load/Retransmit pin FL/ RT LOW for the duration of any
reset operation. (See Table 1.) Subsequently, FL/ RT may
be taken HIGH at will, whenever a retransmit operation is
desired. If not being used, FL/RT also may be tied to
ground, as shown in Figure 27.
BOLD ITALIC = Enhanced Operating Mode
36
BOLD ITALIC = Enhanced Operating Mode.
When depth cascading is not required for a given
2
to ground, while also holding the First
PROGRAMMABLE
ALMOST-EMPTY FLAG (PAE)
HALF-FULL FLAG (WXO/HF)
RCLK
WRITE CLOCK (WCLK)
WRITE ENABLE (WEN)
RXI
FULL FLAG (FF)
LOAD (LD)
FIRST LOAD (FL/ RT )
DATA IN
DURING A RESET
(MUST BE LOW
OPERATION)
Figure 25. Read-Expansion-In Timing,
IDT-Compatible Operating Mode
18
Figure 26. Standalone FIFO
(2048
RESET (RS)
2
D[17:0]
and
LH540235/45
18 / 4096 18)
MODE (EMODE)
ENHANCED
Q[17:0]
READ EXPANSION IN (RXI/ REN
Width Expansion
tiple LH540235/45 devices in parallel. Each device should
be configured for standalone mode, unless the depth of
one single FIFO is not adequate for the application. In this
event, word-width expansion may in principle be used
with either of the two depth-cascading schemes sup-
ported by the LH540235/45 architecture. In practice, the
reliability benefits of interlocked-paralleled operation are
available only with the pipelining scheme, making it the
preferred alternative. (Refer to discussion in a later sec-
tion.)
Word-width expansion is implemented by placing mul-
WRITE EXPANSION IN (WXI/ WEN
18
t
t
XIS
XI
2048 x 18/4096 x 18 Synchronous FIFOs
READ CLOCK (RCLK)
READ ENABLE (REN)
DATA OUT
EMPTY FLAG (EF)
PROGRAMMABLE
ALMOST-FULL FLAG (PAF)
OUTPUT ENABLE (OE)
2
)
2
)
540235-19
540235-21