IDT72V261LA Integrated Device Technology, IDT72V261LA Datasheet - Page 24

• Manufacturer Part Number: IDT72V261LA
• Description: 3.3 Volt Cmos Supersync Fifo
• Manufacturer: Integrated Device Technology

OPTIONAL CONFIGURATIONS
WIDTH EXPANSION CONFIGURATION
control signals of multiple devices. Status flags can be detected from
any one device. The exceptions are the EF and FF functions in IDT
Standard mode and the IR and OR functions in FWFT mode. Because
of variations in skew between RCLK and WCLK, it is possible for EF/FF
deassertion and IR/OR assertion to vary by one cycle between FIFOs.
In IDT Standard mode, such problems can be avoided by creating
NOTES:
1. Use an AND gate in IDT Standard mode, an OR gate in FWFT mode.
2. Do not connect any output control signals directly together.
3. FIFO #1 and FIFO #2 must be the same depth, but may be different word widths.
IDT72V261LA/72V271LA
3.3 VOLT CMOS SuperSync FIFO™ 16,384 x 9 and 32,768 x 9
Word width may be increased simply by connecting together the
GATE
(1)
FIRST WORD FALL THROUGH/
DATA IN
SERIAL INPUT (FWFT/SI)
MASTER RESET (MRS)
PARTIAL RESET (PRS)
FULL FLAG/INPUT READY (FF/IR)
FULL FLAG/INPUT READY (FF/IR) #2
RETRANSMIT (RT)
m + n
PROGRAMMABLE (PAF)
WRITE CLOCK (WCLK)
WRITE ENABLE (WEN)
HALF-FULL FLAG (HF)
Figure 19. Block Diagram of 16,384 x 18 and 32,768 x 18 Width Expansion
D
0
- Dm
LOAD (LD)
m
#1
72V261LA
72V271LA
IDT
FIFO
#1
Dm
m
+1
- Dn
Q
0
24
n
- Qm
composite flags, that is, ANDing EF of every FIFO, and separately
ANDing FF of every FIFO. In FWFT mode, composite flags can be
created by ORing OR of every FIFO, and separately ORing IR of every
FIFO.
72V271LA devices. D0 - D8 from each device form a 18-bit wide input
bus and Q0-Q8 from each device form a 18-bit wide output bus. Any
word width can be attained by adding additional IDT72V261LA/72V271LA
devices.
Figure 21 demonstrates a width expansion using two IDT72V261LA/
72V261LA
72V271LA
FIFO
IDT
#2
READ CLOCK (RCLK)
n
READ ENABLE (REN)
OUTPUT ENABLE (OE)
EMPTY FLAG/OUTPUT READY (EF/OR) #2
EMPTY FLAG/OUTPUT READY (EF/OR) #1
PROGRAMMABLE (PAE)
Qm
+1
- Qn
COMMERCIAL AND INDUSTRIAL
m + n
TEMPERATURE RANGES
DATA OUT
4673 drw 22
GATE
(1)