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INV/NON

GND

GND

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+

SN75LVDM976

SN75LVDM977

SLLS292B – APRIL 1998 – REVISED JANUARY 2000

9-CHANNEL DUAL-MODE TRANSCEIVERS

•

9 Channels for the Data and Control Paths of

the Small Computer Systems Interface (SCSI)

•

Supports Single-Ended and Low-Voltage

Differential (LVD) SCSI

•

CMOS Input Levels ('LVDM976) or TTL Input

Levels ('LVDM977) Available

•

Includes DIFFSENS Comparators on CDE0

•

Single-Ended Receivers Include Noise Pulse

Rejection Circuitry

•

Packaged in Thin Shrink Small-Outline

Package With 20-Mil Terminal Pitch

•

Low Disabled Supply Current 7 mA Maximum

•

Power-Up/Down Glitch Protection

•

•

Pin-Compatible With the SN75976ADGG

High-Voltage Differential Transceiver

The SN75LVDM976 and SN75LVDM977 have nine

transceivers for transmitting or receiving the signals

to or from a SCSI data bus. They offer electrical

compatibility to both the single-ended signaling of

X3.277:1996-SCSI-3 Parallel Interface (Fast-20) and

the new low-voltage differential signaling method of

proposed standard 1142-D SCSI Parallel Interface –

2 (SPI-2).

The differential drivers are nonsymmetrical. The SCSI

bus uses a dc bias on the line to allow terminated fail

safe and wired-OR signaling. This bias can be as

high as 125 mV and induces a difference in the

high-to-low and low-to-high transition times of a

AVAILABLE OPTIONS

symmetrical driver. In order to reduce pulse skew, an

PACKAGE

LVD SCSI driver's output characteristics become

TSSOP (DGG)

nonsymmetrical. In other words, there is more

TSSOP (DGG)

TTL INPUTS

assertion current than negation current to or from the

CMOS INPUT LEVELS

LEVELS

driver. This allows the actual differential signal

0°C to

SN75LVDM976DGG

SN75LVDM977DGG

voltage on the bus to be symmetrical about 0 V. Even

70°C

though

the

driver

output

characteristics

are

nonsymmetrical, the design of the 'LVDM976 drivers

maintains balanced signaling. Balanced means that

the current that flows in each signal line is nearly

equal but opposite in direction and is one of the keys

to the low-noise performance of a differential bus.

(1)

The R suffix designates a taped and reeled package.

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.

PRODUCTION DATA information is current as of publication date.

Copyright © 1998–2000, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.