SN75LBC968 Datasheet, PDF (1/16 Pages) Texas Instruments – 9-CHANNEL BUS TRANSCEIVER WITH ACTIVE TERMINATION

SN75LBC968
9-CHANNEL BUS TRANSCEIVER
WITH ACTIVE TERMINATION
SLLS179C – APRIL 1994 – REVISED JANUARY 1999
D Nine Single-Ended SCSI Transceiver
Channels With Active Termination
DL PACKAGE
(TOP VIEW)
D Programmable Drivers Provide Active
Negation (Totem Pole) or Wired-OR (Open
Drain) Outputs
D 24-mA Current-Mode Active Termination
With Common Nine-Channel Bus Enable
D Low Output Capacitance Presented to SCSI
GND 1
TE 2
GND 3
1A 4
1DE/RE 5
2A 6
56 8B
55 GND
54 CE
53 NC
52 NC
51 NC
Bus, 13.5 pF Typ
D 3.3 V Compatible Logic Inputs Provide
2DE/RE 7
3A 8
50 7B
49 NC
Bridge from 3 V Controllers to 5 V SCSI
3DE/RE 9
48 6B
Bus
4A ¹⁰ 47 NC
D Designed to Operate at 10-Million Data
Transfers Per Second (Fast-SCSI)
D Controlled Driver Rise and Fall Times
5 ns Min
D High-Receiver Input-Voltage Hysteresis
500 mV Typ
D Receiver Input-Noise Pulse Filter
5 ns Typ
D Each Driver and Receiver Meets ANSI
4DE/RE ¹¹
V_CC1 ¹²
GND ¹³
GND ¹⁴
GND ¹⁵
GND ¹⁶
GND ¹⁷
V_CC ¹⁸
5A ¹⁹
5DE/RE ²⁰
46 _5B
45 _VCC
44 _GND
43 _GND
42 _GND
41 _GND
40 _GND
39 _VCC
38 _NC
37 _4B
X3.131-1994 (SCSI-2) and the Proposed
6A ^{21 36} NC
SCSI-3 Standards
6DE/RE ^{22 35} 3B
D Power-Up/Power-Down Glitch Protection
D High Impedance Driver With V_CC at 0 V
description
The SN75LBC968 is a nine-channel transceiver
7A ²³
7DE/RE ²⁴
8A ²⁵
8DE/RE ²⁶
9A ²⁷
9DE/RE ²⁸
34 _NC
33 _2B
32 _NC
31 _1B
30 _NC
29 _9B
with active termination that drives and receives
the signals from the single-ended, parallel data
NC – No internal connection
buses such as the Small Computer-Systems
Interface (SCSI) bus. The features of the line drivers, receivers, and active-termination circuits provide the
optimum signal-to-noise ratios for reliable data transmission. Integration of the termination and transceivers in
the LinBiCMOS™ process provides the necessary analog-circuit performance, has low quiescent power, and
reduces the capacitance presented to the bus over separate termination and I/O circuits.
The transceivers of the SN75LBC968 can be enabled to function as totem-pole or open-drain outputs. The
open-drain mode drives the wired-OR lines of SCSI (BSY, SEL, and RST) by inputting the data to the direction
control input DE/RE instead of the A input. When driving the data through the A input, the outputs become totem
poles and provide active signal negation for a higher voltage level on low-to-high signal transitions on heavily
loaded buses. In either mode, the turn-on and turn-off output transition times are limited to minimize crosstalk
through capacitive coupling to adjacent lines and RF emissions from the cable. The receivers are also designed
for optimum analog performance by precisely controlling the input-voltage thresholds, providing wide
input-voltage hysteresis and including an input-noise filter. These features significantly increase the likelihood
of detecting only the desired data signal and rejecting noise.
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.
LinBiCMOS is a trademark of Texas 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.
Copyright © 1999, Texas Instruments Incorporated
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