SN75976A, SN55976A

9-CHANNEL DIFFERENTIAL TRANSCEIVER

SLLS218B – MAY 1995 – REVISED MAY 1997

1

POST OFFICE BOX 655303

for the SN75LBC976

Data Transfers per Second (Fast-20 SCSI)

Control Paths of the Small Computer

Systems Interface (SCSI) and Intelligent

Peripheral Interface (IPI)

Small-Outline Package with 25-Mil Terminal

Pitch (DL) and Thin Shrink Small-Outline

Package with 20-Mil Terminal Pitch (DGG)

Flat Pack (WD)

Exceeds 12 kV

description

The SN75976A is an improved replacement for

the

industry’s

first

9-channel

RS-485

transceiver — the SN75LBC976. The A version

offers improved switching performance, a smaller

package, and higher ESD protection. The

SN75976A is offered in two versions. The ’976A2

skew limits of 4 ns for the differential drivers and

5 ns for the differential receivers complies with the

recommended skew budget of the Fast-20 SCSI

standard for data transfer rates up to 20 million

transfers per second. The ’976A1 supports the

Fast SCSI skew budget for 10 million

transfers per second. The skew limit ensures that the propagation delay times, not only from channel-to-channel

but from device-to-device, are closely matched for the tight skew budgets associated with high-speed parallel

data buses.

The patented thermal enhancements made to the 56-pin shrink small-outline package (SSOP) of the SN75976

have been applied to the new, thin shrink, small-outline package (TSSOP). The TSSOP package offers even

less board area requirements than the SSOP while reducing the package height to 1 mm. This provides more

board area and allows component mounting to both sides of the printed circuit boards for low-profile,

space-restricted applications such as small form-factor hard disk drives.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

Terminals 13 through 17 and 40 through 44 are

connected together to the package lead frame

and signal ground.

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

GND

BSR

CRE

1A

1DE/RE

2A

2DE/RE

3A

3DE/RE

4A

4DE/RE

GND

GND

GND

GND

GND

5A

5DE/RE

6A

6DE/RE

7A

7DE/RE

8A

8DE/RE

9A

9DE/RE

CDE2

CDE1

CDE0

9B+

8B+

7B+

6B+

GND

GND

GND

GND

GND

5B+

4B+

3B+

2B+

1B+

SN75976A DGG or DL

SN55976A WD

(TOP VIEW)

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

Copyright

© 1997, Texas Instruments Incorporated