Philips Semiconductors

Product specification

CBT6820

20-bit bus switch with precharged outputs and

Schottky undershoot protection for live insertion

2

1999 Apr 05

853–2152 21177

FEATURES

changes

during live insertion

DESCRIPTION

The CBT6820 provides twenty bits of high-speed TTL-compatible

bus switching. The low on-state resistance of the switch allows

bi-directional connections to be made while adding near-zero

propagation delay. The device also precharges the B port to a

user-selectable bias voltage (BIASV) to minimize live-insertion

noise.

The device is organized as two 10-bit switch with individual enable

(OE) input. When OE is low, the switch is on and port A is

connected to port B. When OE is high, the switch between port A

and port B is open and the B port is precharged to BIASV through

the equivalent of a 10-k

Ω resistor.

Special clamp circuitry and Schottky diode clamps to ground are

used to prevent an under voltage on the A side (Vin

< GND) from

causing the B side precharge voltage to drop below the ‘‘1” state.

PIN CONFIGURATION

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

21

22

23

24

41

42

43

44

45

46

47

48

SA00520

1A1

1A2

1A3

1A4

1A5

1A6

GND

1A7

1A8

1A9

1A10

2A1

2A2

2A3

GND

2A4

2A5

2A6

2A7

2A8

2A9

2A10

1OE

2OE

1B1

1B2

1B3

1B4

1B5

GND

1B6

1B7

1B8

1B9

1B10

2B1

2B2

2B3

GND

2B4

2B5

2B6

2B7

2B8

2B9

2B10

BIASV

QUICK REFERENCE DATA

SYMBOL

PARAMETER

CONDITIONS

TYPICAL

UNIT

Propagation delay

An to Bn or Bn to An

0.25

ns

Input capacitance

4.5

pF

Input/output capacitance

9.5

pF

ORDERING INFORMATION

PACKAGES

TEMPERATURE RANGE

OUTSIDE NORTH AMERICA

NORTH AMERICA

DWG NUMBER

48-Pin Plastic TSSOP Type II

–40

°C to +85°C

CBT6820 DGG

CBT6820 DGG

SOT362–1