Datasheet

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DESCRIPTION/ORDERING INFORMATION (CONTINUED)
SN74CB3Q3251
1-OF-8 FET MULTIPLEXER/DEMULTIPLEXER
2.5-V/3.3-V LOW-VOLTAGE HIGH-BANDWIDTH BUS SWITCH
SCDS173A – AUGUST 2004 – REVISED MARCH 2005
The SN74CB3Q3251 is a 1-of-8 multiplexer/demultiplexer with a single output-enable ( OE) input. The select (S0,
S1, S2) inputs control the data path of the multiplexer/demultiplexer. When OE is low, the
multiplexer/demultiplexer is enabled, and the A port is connected to the B port, allowing bidirectional data flow
between ports. When OE is high, the multiplexer/demultiplexer is disabled, and a high-impedance state exists
between the A and B ports.
This device is fully specified for partial-power-down applications using I
off
. The I
off
circuitry prevents damaging
current backflow through the device when it is powered down. The device has isolation during power off.
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.
ORDERING INFORMATION
T
A
PACKAGE
(1)
ORDERABLE PART NUMBER TOP-SIDE MARKING
QFN – RGY Tape and reel SN74CB3Q3251RGYR BU251
SSOP (QSOP) – DBQ Tape and reel SN74CB3Q3251DBQR BU251
–40°C to 85°C Tube SN74CB3Q3251PW
TSSOP – PW BU251
Tape and reel SN74CB3Q3251PWR
TVSOP – DGV Tape and reel SN74CB3Q3251DGVR BU251
(1) Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available at
www.ti.com/sc/package.
FUNCTION TABLE
INPUTS
INPUT/OUTPUT
FUNCTION
A
OE S2 S1 S0
L L L L B1 A port = B1 port
L L L H B2 A port = B2 port
L L H L B3 A port = B3 port
L L H H B4 A port = B4 port
L H L L B5 A port = B5 port
L H L H B6 A port = B6 port
L H H L B7 A port = B7 port
L H H H B8 A port = B8 port
H X X X Z Disconnect
2