SN74CBT6800C

10BIT FET BUS SWITCH WITH PRECHARGED OUTPUTS

5V BUS SWITCH WITH -2V UNDERSHOOT PROTECTION

SCDS138 − OCTOBER 2003

2

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

description/ordering information (continued)

The SN74CBT6800C 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 BIASV through the equivalent of a 10-k

Ω resistor when ON is high, or if the device is

powered down (VCC = 0 V).

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.

This device is fully specified for partial-power-down applications using Ioff. The Ioff feature ensures that

damaging current will not 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, ON 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.

ORDERING INFORMATION

TA

PACKAGE†

ORDERABLE

PART NUMBER

TOP-SIDE

MARKING

SOIC − DW

Tube

SN74CBT6800CDW

CBT6800C

SOIC − DW

Tape and reel

SN74CBT6800CDWR

CBT6800C

SSOP − DB

Tube

SN74CBT6800CDB

CT6800C

−40

°C to 85°C

SSOP − DB

Tape and reel

SN74CBT6800CDBR

CT6800C

−40

°C to 85°C

SSOP (QSOP) − DBQ

Tape and reel

SN74CBT6800CDBQR

CBT6800C

TSSOP − PW

Tube

SN74CBT6800CPW

CT6800C

TSSOP − PW

Tape and reel

SN74CBT6800CPWR

CT6800C

TVSOP − DGV

Tape and reel

SN74CBT6800CDGVR

CT6800C

† 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