IDT72805LB
IDT72815LB
IDT72825LB
IDT72835LB
IDT72845LB
CMOS DUAL SyncFIFO™
DUAL 256 x 18, DUAL 512 x 18,
DUAL 1,024 x 18, DUAL 2,048 x 18
and DUAL 4,096 x 18
• Single or double register-buffered Empty and Full Flags
FEATURES:
• Easily expandable in depth and width
• The IDT72805LB is equivalent to two IDT72205LB 256 x 18 FIFOs
• The IDT72815LB is equivalent to two IDT72215LB 512 x 18 FIFOs
• The IDT72825LBis equivalenttotwoIDT72225LB1,024 x 18FIFOs
• The IDT72835LBis equivalenttotwoIDT72235LB2,048 x 18FIFOs
• The IDT72845LBis equivalenttotwoIDT72245LB4,096 x 18FIFOs
• Offers optimal combination of large capacity (8K), high speed,
design flexibility, and small footprint
• Asynchronous or coincident Read and Write clocks
• Asynchronous or synchronous programmable Almost-Empty
and Almost-Full flags with default settings
• Half-Full flag capability
• Output Enable puts output data bus in high-impedance state
• High-performance submicron CMOS technology
• Available in the 128-pin Thin Quad Flatpack (TQFP). Also
available for the IDT72805LB/72815LB/72825LB, in the 121-lead,
16 x 16 mm plastic Ball Grid Array (PBGA)
• Ideal for the following applications:
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Network switching
Two level prioritization of parallel data
Bidirectional data transfer
Bus-matching between 18-bit and 36-bit data paths
Width expansion to 36-bit per package
Depth expansion to 8,192 words per package
• Industrial temperature range (–40°C to +85°C) is available
DESCRIPTION:
TheIDT72805LB/72815LB/72825LB/72835LB/72845LBaredual18-bit-wide
synchronous(clocked)First-in,First-out(FIFO)memories.OnedualIDT72805LB/
72815LB/72825LB/72835LB/72845LB device is functionally equivalent to two
• 10ns read/write cycle time, 6.5ns access time
• IDT Standard or First Word Fall Through timing
FUNCTIONAL BLOCK DIAGRAM
HFA/(WXOA)
PAEA
FFA/IRA
EFA/
ORA
WCLKA
WCLKB
DA0-DA17
WENA
LDA
WENB
DB0-DB17
LDB
PAFA
INPUT
OFFSET
INPUT
OFFSET
REGISTER
REGISTER
REGISTER
REGISTER
FFB/IRB
FLAG
PAFB
WRITE
FLAG
LOGIC
WRITE
EFB/ORB
PAEB
HFB/(WXOB)
CONTROL
LOGIC
RAM
LOGIC
CONTROL
LOGIC
ARRAY
RAM
256 x 18
512 x 18
1,024 x 18
2,048 x 18
4,096 x 18
ARRAY
256 x 18
512 x 18
1,024 x 18
2,048 x 18
4,096 x 18
READ
POINTER
WRITE
READ
POINTER
WRITE
POINTER
POINTER
READ
CONTROL
LOGIC
FLA
WXIA
(HFA)/WXOA
RXIA
READ
CONTROL
LOGIC
EXPANSION
LOGIC
EXPANSION
LOGIC
OUTPUT
REGISTER
OUTPUT
RXOA
REGISTER
RESET
LOGIC
RSA
RESET
LOGIC
RSB
RXOB
RXIB
(HFB)/WXOB
WXIB
FLB
RCLKB
RCLKA
OEB
QA0-QA17
RENB
RENA
OEA
QB0-QB17
3139 drw 01
IDTandtheIDTlogoareregisteredtrademarks.TheSyncFIFOisatrademarkofIntegratedDeviceTechnology,Inc.
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
FEBRUARY 2003
1
2003 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice.
DSC-3139/4