www.ti.com

DGG, DGV, OR DL PACKAGE

(TOP VIEW)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

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

BIASV

1A1

1A2

1A3

1A4

1A5

1A6

GND

1A7

1A8

1A9

1A10

1A11

1A12

2A1

2A2

2A3

GND

2A4

2A5

2A6

2A7

2A8

2A9

2A10

2A11

2A12

1OE

2OE

1B1

1B2

1B3

1B4

1B5

GND

1B6

1B7

1B8

1B9

1B10

1B11

1B12

2B1

2B2

2B3

GND

2B4

2B5

2B6

2B7

2B8

2B9

2B10

2B11

2B12

SN74CB3Q16811

24-BIT SWITCH WITH PRECHARGED OUTPUTS

2.5-V/3.3-V LOW-VOLTAGE FET BUS SWITCH

SCDS153B – OCTOBER 2003 – REVISED MARCH 2005

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 ensures that any glitch produced by insertion (or removal) of the card does 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.

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

Table 1. FUNCTION TABLE

(EACH 12-BIT BUS SWITCH)

INPUT

INPUT/OUTPUT

FUNCTION

OE

A

L

B

A port = B port

Disconnect

H

Z

B port = BIASV

2