SN74ALVCH16271
12-BIT TO 24-BIT MULTIPLEXED BUS EXCHANGER
WITH 3-STATE OUTPUTS
SCES017E – JULY 1995 – REVISED FEBRUARY 1999
DGG OR DL PACKAGE
(TOP VIEW)
Member of the Texas Instruments
Widebus Family
EPIC (Enhanced-Performance Implanted
CMOS) Submicron Process
OEA
LE1B
2B3
GND
2B2
1
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
OEB
CLKENA2
2B4
GND
2B5
2B6
2
ESD Protection Exceeds 2000 V Per
MIL-STD-883, Method 3015; Exceeds 200 V
Using Machine Model (C = 200 pF, R = 0)
3
4
5
Latch-Up Performance Exceeds 250 mA Per
JESD 17
2B1
6
V
7
V
CC
CC
A1
A2
A3
GND
A4
8
Bus Hold on Data Inputs Eliminates the
Need for External Pullup/Pulldown
Resistors
2B7
2B8
2B9
9
10
11
12
GND
2B10
2B11
2B12
1B12
1B11
1B10
GND
1B9
Package Options Include Plastic Shrink
Small-Outline (DL) and Thin Shrink
Small-Outline (DGG) Packages
A5 13
A6 14
A7 15
description
A8 16
This 12-bit to 24-bit bus exchanger is designed for
1.65-V to 3.6-V V operation.
A9 17
CC
GND 18
A10 19
A11 20
A12 21
The SN74ALVCH16271 is intended for
applications in which two separate data paths
must be multiplexed onto, or demultiplexed from,
a single data path. This device is particularly
suitable as an interface between conventional
DRAMs and high-speed microprocessors.
1B8
1B7
V
22
V
CC
CC
1B1 23
1B2 24
GND 25
1B3 26
LE2B 27
SEL 28
1B6
1B5
GND
1B4
CLKENA1
CLK
A data is stored in the internal A-to-B registers on
the low-to-high transition of the clock (CLK) input,
provided that the clock-enable (CLKENA) inputs
are low. Proper control of these inputs allows two
sequential 12-bit words to be presented as a
24-bit word on the B port.
Transparent latches in the B-to-A path 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, the output enables 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 SN74ALVCH16271 is characterized for operation from –40°C to 85°C.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
EPIC and Widebus are trademarks of Texas Instruments Incorporated.
Copyright 1999, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
1
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