Texas Instruments SN75LBC978DL, SN75LBC978DLR Datasheet

SN75LBC978

9-CHANNEL DIFFERENTIAL TRANSCEIVER

SLLS134E – APRIL 1992 – REVISED MA Y 1997

1

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

D

Nine Differential Channels for the Data and
Control Paths of the Differential Small
Computer Systems Interface (SCSI)

D

Meets or Exceeds the Requirements of
ANSI Standard RS-485 and ISO
8482:1987(E)

D

Packaged in Shrink Small-Outline Package
With 25-mil Terminal Pitch

D

Designed to Operate at 10 Million Transfers
Per Second

D

Low Disabled Supply Current

1.4 mA Typ

D

Thermal Shutdown Protection

D

Power-Up/Power-Down Glitch Protection

D

Positive and Negative Output-Current
Limiting

D

Open-Circuit Fail-Safe Receiver Design

description

The SN75LBC978 is a nine-channel differential
transceiver based on the 75LBC176 LinASIC
cell. Use of TI’s LinBiCMOS

†

process technolo­gy allows the power reduction necessary to
integrate nine differential balanced transceivers

†

.
On-chip enabling logic makes this device
applicable for the data path (eight data bits plus
parity) and the control path (nine bits) for the Small
Computer Systems Interface (SCSI) standard.
The WRAP function allows in-circuit testing and
wired-OR channels for the BSY, RST, and SEL
signals of the SCSI bus.

The SN75LBC978 is packaged in a shrink
small-outline package (DL) with improved thermal
characteristics using heat-sink terminals. This
package is ideal for low-profile, space-restricted
applications such as hard disk drives.

The switching speed of the SN75LBC978 is sufficient to transfer data over the data bus at 10 million transfers
per second. Each of the nine identical channels conforms to the requirements of the ANSI RS-485 and
ISO 8482:1987(E) standards referenced by ANSI X3.131-1993 (SCSI-2) and the proposed SCSI-3 standards.

The SN75LBC978 is characterized for operation from 0°C to 70°C.

LinASIC and LinBiCMOS are trademarks of Texas Instruments Incorporated.

†

Patent Pending

Copyright  1997, T exas Instruments Incorporated

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.

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

NC
WRAP2
WRAP1

1A

1DE/RE

2A

2DE/RE

3A

3DE/RE

4A

4DE/RE

V

CC

GND
GND
GND
GND
GND

V

CC

5A

5DE/RE

6A

6DE/RE

7A

7DE/RE

8A

8DE/RE

9A

9DE/RE

NC
NC
CE
9B+
9B–
8B+
8B–
7B+
7B–
6B+
6B–
V

CC

GND
GND
GND
GND
GND
V

CC

5B+
5B–
4B+
4B–
3B+
3B–
2B+
2B–
1B+
1B–

DL PACKAGE

(TOP VIEW)

Pins 13 through 17 and 40 through 44 are
connected together to the package lead
frame and signal ground.

SN75LBC978
9-CHANNEL DIFFERENTIAL TRANSCEIVER

SLLS134E – APRIL 1992 – REVISED MA Y 1997

2

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

logic diagram (positive logic)

1B–

1B+

7B–

7B+

2B–

2B+

3B–

3B+

4B–

4B+

5B–

5B+

6B–

6B+

8B–

8B+

9B–

9B+

1A

WRAP1

CE

1DE/RE

2A

2DE/RE

3A

3DE/RE

4A

4DE/RE

5A

5DE/RE

6A

6DE/RE

8A

8DE/RE

9A

9DE/RE

7DE/RE

7A

WRAP2

Channel 2

Channel 3

Channel 4

Channel 5

Channel 6

Channel 8

Channel 9

4
3

5

54

6
7
8
9

10
11

19
20

21
22

23

2

24

25
26

27
28

30
29

32
31

34
33

36
35

38
37
47
46

49
48

51
50
53
52

SN75LBC978

9-CHANNEL DIFFERENTIAL TRANSCEIVER

SLLS134E – APRIL 1992 – REVISED MA Y 1997

3

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

schematics of inputs and outputs

ALL INPUTS EXCEPT CE INPUT CE

B+ AND B– I/O PORTS RECEIVER OUTPUT

A Output

100 kΩ
B+ Only

100 kΩ
B– Only

18 kΩ

12 kΩ

1 kΩ

V

CC

Driver

Receiver

3 kΩ

B+ or B–

Input

V

CC

22 kΩ

50 kΩ

300 Ω

Input

V

CC

300 Ω

V

CC

absolute maximum ratings over operating free-air temperature range (unless otherwise noted)

†

Supply voltage range, V

CC

(see Note 1) –0.3 V to 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Bus voltage range –10 V to 15 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Data I/O and control (A-side) voltage range –0.3 V to 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Continuous power dissipation internally limited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operating free-air temperature range, T

A

0°C to 70°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Storage temperature range, T

stg

–65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds 260°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

†

Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

NOTE 1: All voltage values are dc and with respect to GND.

SN75LBC978
9-CHANNEL DIFFERENTIAL TRANSCEIVER

SLLS134E – APRIL 1992 – REVISED MA Y 1997

4

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

recommended operating conditions

MIN NOM MAX UNIT

Supply voltage, V

CC

4.75 5 5.25 V

p

12

Voltage at any bus terminal (separately or common-mode), V

O

,

V

I

, or

V

IC

B

+ or B–

–7

V

High-level input voltage, V

IH

All except B+ and B– 2 V

Low-level input voltage, V

IL

All except B+ and B– 0.8 V

p

B+ or B– –60 mA

High-level output current, I

OH

A –8 mA

p

B+ or B– 60 mA

Low-level output current, I

OL

A 8 mA

Operating free-air temperature, T

A

0 70 °C

device electrical characteristics over recommended ranges of operating conditions

PARAMETER TEST CONDITIONS MIN TYP†MAX UNIT

p

A, WRAP, DE/RE

–200 µA

IIHHigh-level input current

CE

V

IH

= 2

V

100 µA

p

A, WRAP, DE/RE

See Figure 1

–200 µA

IILLow-level input current

CE

V

IL

= 0.8

V

100 µA

All drivers and receivers
disabled

CE at 0 V 1.4 3 mA

I

CC

Supply current

All receivers enabled

No load,
CE at 5 V,

VID = 5 V,
WRAP and DE/RE

at 0 V

29 45 mA

All drivers enabled

No load,
WRAP at 0 V

CE and DE/RE at 5 V,

7 10 mA

COBus port output capacitance B+ or B– 19 pF

p

p

One driver 460 pF

C

pd

Power dissipation capacitance

One receiver 40 pF

driver electrical characteristics over recommended ranges of operating conditions (unless
otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

|VOD| Differential output voltage V

test

= –7 V to 12 V , See Figure 2 1 2 V

I

OS

Output short-circuit current See Figure 3 ±250 mA

I

OZ

High-impedance-state output current See receiver input current

SN75LBC978

9-CHANNEL DIFFERENTIAL TRANSCEIVER

SLLS134E – APRIL 1992 – REVISED MA Y 1997

5

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

receiver electrical characteristics over recommended ranges of operating conditions (unless
otherwise noted) (see Figure 3)

PARAMETER TEST CONDITIONS MIN TYP†MAX UNIT

V

OH

High-level output voltage VID = 200 mV , IOH = –8 mA 2.5 V

V

OL

Low-level output voltage VID = –200 mV, IOL = 8 mA 0.8 V

V

IT+

Differential-input high-level threshold voltage IOH = –8 mA 0.2 V

V

IT–

Differential-input low-level threshold voltage IOL = 8 mA –0.2 V

V

hys

Receiver input hysteresis voltage (V

IT+

– V

IT–

) 45 mV

VI = 12 V,
Other input at 0 V

VCC = 5 V,

0.7 1 mA

p

VI = 12 V,
Other input at 0 V

VCC = 0 V,

0.8 1 mA

IIReceiver input current

B+ and B

–

VI = –7 V,
Other input at 0 V

VCC = 5 V,

–0.5 –0.8 mA

VI = –7 V,
Other input at 0 V

VCC = 0 V,

–0.4 –0.8 mA

p

p

VO = GND –200

IOZHigh-impedance-state output current

VO = V

CC

50

µ

A

driver switching characteristics over recommended ranges of operating conditions (unless
otherwise noted)

PARAMETER TEST CONDITIONS MIN

TYP

†

MAX UNIT

See Figure 4 11.8 26.4

t

d(OD)

Differential delay time, high- to low-level output (t

d(ODH)

) or low-

-

p

VCC = 5 V,
See Figure 4

TA = 25°C,

14 18 22

ns

()

to high-level out ut (t

d(ODL)

)

VCC = 5 V,
See Figure 4

TA = 70°C,

18 22 26

Skew limit, the maximum difference in propagation delay times

15

t

sk(lim)

,gy

between any two drivers on any two devices

VCC = 5 V,

See Note 2 8

ns

t

sk(p)

Pulse skew (|t

d(ODL)

– t

d(ODH)

|)

0 6 ns

t

t

Transition time (tr or tf)

See Figure 4

10 ns

receiver switching characteristics over recommended ranges of operating conditions (unless
otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP†MAX UNIT

See Figure 5

19.5 30.7

t

pd

Propagation delay time, high- to low-level output (t

PHL

) or low- to

-

p

VCC = 5 V,
See Figure 5

TA = 25°C,

20.2 24.7 29.2
ns

high-level out ut (t

PLH

)

VCC = 5 V,
See Figure 5

TA = 70°C,

21.1 25.6 30.1

Skew limit, the maximum difference in propagation delay times

12

t

sk(lim)

,gy

between any two drivers on any two devices

VCC = 5 V,

See Note 2 9

ns

t

sk(p)

Pulse skew (|t

PHL

– t

PLH

|)

2 6 ns

t

t

Transition time (tr or tf)

See Figure 5

3 ns

†

All typical values are at VCC = 5 V, TA = 25°C.

‡

Cpd determines the no-load dynamic current consumption; IS = Cpd ⋅ VCC ⋅ f + ICC.

NOTE 2: This specification applies to any 5°C band within the operating temperature range.