SN74ALVCH16271
12-BIT TO 24-BIT MULTIPLEXED BUS EXCHANGER
WITH 3-STATE OUTPUTS
www.ti.com
SCES017G–JULY 1995–REVISED SEPTEMBER 2004
FEATURES
DGG OR DL PACKAGE
(TOP VIEW)
•
•
•
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Member of the Texas Instruments Widebus™
Family
OEA
LE1B
2B3
1
2
3
4
5
6
7
8
9
10
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
Bus Hold on Data Inputs Eliminates the Need
for External Pullup/Pulldown Resistors
Latch-Up Performance Exceeds 250 mA Per
JESD 17
GND
2B2
GND
2B5
ESD Protection Exceeds JESD 22
- 2000-V Human-Body Model (A114-A)
- 200-V Machine Model (A115-A)
2B1
2B6
V
CC
V
CC
A1
A2
A3
2B7
2B8
2B9
DESCRIPTION/ORDERING INFORMATION
This 12-bit to 24-bit bus exchanger is designed for
1.65-V to 3.6-V VCC operation.
GND 11
A4 12
A5 13
GND
2B10
2B11
2B12
1B12
1B11
1B10
GND
1B9
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.
14
15
16
17
A6
A7
A8
A9
GND 18
19
20
21
22
23
24
25
26
27
28
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.
A10
A11
A12
1B8
1B7
V
CC
V
CC
1B1
1B2
1B6
1B5
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).
GND
1B3
LE2B
SEL
GND
1B4
CLKENA1
CLK
line
space
To ensure the high-impedance state during power up or power down, the output enables should be tied to VCC
through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the
driver.
Active bus-hold circuitry holds unused or undriven inputs at a valid logic state. Use of pullup or pulldown resistors
with the bus-hold circuitry is not recommended.
ORDERING INFORMATION
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
TA
PACKAGE(1)
Tube
SN74ALVCH16271DL
SN74ALVCH16271DLR
SSOP - DL
TSSOP - DGG
ALVCH16271
-40°C to 85°C
Tape and reel
Tape and reel
SN74ALVCH16271DGGR ALVCH16271
(1) Package drawings, standard packing quantities, thermal data, symbolization, and PCB design
guidelines are available at www.ti.com/sc/package.
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.
Widebus is a trademark of Texas Instruments.
PRODUCTION DATA information is current as of publication date.
Copyright © 1995–2004, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.