Datasheet
SN74ALVCH16272
12-BIT TO 24-BIT MULTIPLEXED BUS EXCHANGER
WITH 3-STATE OUTPUTS
SCES057C – OCTOBER 1995 – REVISED FEBRUARY 1999
3–75
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
D Member of the Texas Instruments
Widebus Family
D EPIC (Enhanced-Performance Implanted
CMOS) Submicron Process
D Bus Hold on Data Inputs Eliminates
the Need for External Pullup/Pulldown
Resistors
D Packaged in Plastic Shrink Small-Outline
(DL) and Thin Shrink Small-Outline (DGG)
Packages
description
This 12-bit to 24-bit bus exchanger is designed for
1.65-V to 3.3-V V
CC
operation.
The SN74ALVCH16272 is intended for applica-
tions where two separate datapaths must be
multiplexed onto, or demultiplexed from, a single
datapath. This device is particularly suitable as an
interface between conventional DRAMs and
high-speed microprocessors.
Data from the A inputs is stored in the internal
registers on the low-to-high transition of the clock
(CLK) input, when the CLKENA
inputs are low. A
two-stage pipeline is provided in each of the
A-to-1B and A-to-2B paths to serve as a shallow
write buffer.
Transparent latches are provided in the B-to-A
path to allow asynchronous operation to maximize
memory access throughput. These latches
transfer data when the latch-enable (LE
) inputs
are low. The select (SEL
) line selects 1B or 2B
data for the A outputs. Data flow is controlled by
the active-low output enables (OEA
, OEB).
To ensure the high-impedance state during power up or power down, OE
should be tied to V
CC
through a pullup
resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
Active bus-hold circuitry is provided to hold unused or floating data inputs at a valid logic level.
The SN74ALVCH16272 is characterized for operation from –40°C to 85°C.
PRODUCT PREVIEW
Copyright 1999, Texas Instruments Incorporated
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
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OEA
LE1B
2B3
GND
2B2
2B1
V
CC
A1
A2
A3
GND
A4
A5
A6
A7
A8
A9
GND
A10
A11
A12
V
CC
1B1
1B2
GND
1B3
LE2B
SEL
OEB
CLKENA2
2B4
GND
2B5
2B6
V
CC
2B7
2B8
2B9
GND
2B10
2B11
2B12
1B12
1B11
1B10
GND
1B9
1B8
1B7
V
CC
1B6
1B5
GND
1B4
CLKENA1
CLK
EPIC and Widebus are trademarks of Texas Instruments Incorporated.