SN74CB3Q6800

10BIT FET BUS SWITCH WITH PRECHARGED OUTPUTS

2.5V/3.3V LOW VOLTAGE HIGHBANDWIDTH BUS SWITCH

SCDS142A − OCTOBER 2003 − REVISED NOVEMBER 2003

2

POST OFFICE BOX 655303

description/ordering information

The SN74CB3Q6800 is a high-bandwidth FET bus switch utilizing a charge pump to elevate the gate voltage

allows for minimal propagation delay and supports rail-to-rail switching on the data input/output (I/O) ports. The

device also features low data I/O capacitance to minimize capacitive loading and signal distortion on the data

bus. Specifically designed to support high-bandwidth applications, the SN74CB3Q6800 provides an optimized

interface solution ideally suited for broadband communications, networking, and data-intensive computing

systems.

The SN74CB3Q6800 is a 10-bit bus switch with a single output-enable (ON) input. When ON is low, the 10-bit

bus switch is ON and the A port is connected to the B port, allowing bidirectional data flow between ports. When

ON is high, the 10-bit bus switch is OFF and a high-impedance state exists between the A and B ports. The B

port is precharged to bias voltage (BIASV) through the equivalent of a 10-k

Ω resistor when ON is high, or if the

During insertion (or removal) of a card into (or from) an active bus, the card’s output voltage may be close to

GND. When the connector pins make contact, the card’s parasitic capacitance tries to force the bus signal to

GND, creating a possible glitch on the active bus. This glitching effect can be reduced by using a bus switch

with precharged bias voltage (BIASV) of the bus switch equal to the input threshold voltage level of the receivers

on the active bus. This method will ensure that any glitch produced by insertion (or removal) of the card will not

cross the input threshold region of the receivers on the active bus, minimizing the effects of live-insertion noise.

current backflow through the device when it is powered down. The device has isolation during power off.

resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

ORDERING INFORMATION

TA

PACKAGE†

ORDERABLE

PART NUMBER

TOP-SIDE

MARKING

SSOP (QSOP) − DBQ

Tape and reel

SN74CB3Q6800DBQR

CB3Q6800

−40

°C to 85°C

TSSOP − PW

Tube

SN74CB3Q6800PW

BY800

−40

°C to 85°C

TSSOP − PW

Tape and reel

SN74CB3Q6800PWR

BY800

TVSOP − DGV

Tape and reel

SN74CB3Q6800DGVR

BY800

† Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines

are available at www.ti.com/sc/package.

FUNCTION TABLE

INPUT

INPUT/OUTPUT

FUNCTION

INPUT

ON

INPUT/OUTPUT

A

FUNCTION

L

B

A port = B port

H

Z

Disconnect

B port = BIASV