Datasheet
SCDS154B − OCTOBER 2003 − REVISED DECEMBER 2004
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
description/ordering information (continued)
The SN74CB3Q3244 is organized as two 4-bit bus switches with separate output-enable (1OE, 2OE) inputs.
It can be used as two 4-bit bus switches or as one 8-bit bus switch. When OE
is low, the associated 4-bit bus
switch is ON, and the A port is connected to the B port, allowing bidirectional data flow between ports. When
OE
is high, the associated 4-bit bus switch is OFF, and the 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
†
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
QFN − RGY Tape and reel SN74CB3Q3244RGYR BU244
SOIC − DW
Tube SN74CB3Q3244DW
CB3Q3244
SOIC − DW
Tape and reel SN74CB3Q3244DWR
CB3Q3244
SSOP − DB Tape and reel SN74CB3Q3244DBR BU244
−40°C to 85°C
SSOP (QSOP) − DBQ Tape and reel SN74CB3Q3244DBQR CB3Q3244
−40 C to 85 C
TSSOP − PW
Tube SN74CB3Q3244PW
BU244
TSSOP − PW
Tape and reel SN74CB3Q3244PWR
BU244
TVSOP − DGV Tape and reel SN74CB3Q3244DGVR BU244
VFBGA − GQN Tape and reel SN74CB3Q3244GQNR BU244
†
Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines
are available at www.ti.com/sc/package.
terminal assignments
1234
A 1A1 1OE V
CC
2OE
B 1A2 2A4 2B4 1B1
C 1A3 2B3 2A3 1B2
D 1A4 2A2 2B2 1B3
E GND 2B1 2A1 1B4
FUNCTION TABLE
(each 4-bit bus switch)
INPUT
INPUT/OUTPUT
FUNCTION
INPUT
OE
INPUT/OUTPUT
A
FUNCTION
L B A port = B port
H Z Disconnect
GQN PACKAGE
(TOP VIEW)
1234
A
B
C
D
E