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Part: 5962-9689301QXA
Category:
Interface and Interconnect
-> RS-485
Description: ti SN55976A, 9-Channel Differential Transceiver
Company: Texas Instruments, Inc.
Datasheet: Download 5962-9689301QXA datasheet File size : 279 kB
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Datasheet text preview:
SN75976A, SN55976A 9-CHANNEL DIFFERENTIAL TRANSCEIVER
SLLS218B MAY 1995 REVISED MAY 1997
D D D D D D D D D D D
Improved Speed and Package Replacement for the SN75LBC976 Designed to Operate at up to 20 Million Data Transfers per Second (Fast-20 SCSI) Nine Differential Channels for the Data and Control Paths of the Small Computer Systems Interface (SCSI) and Intelligent Peripheral Interface (IPI) SN75976A Packaged in Shrink Small-Outline Package with 25-Mil Terminal Pitch (DL) and Thin Shrink Small-Outline Package with 20-Mil Terminal Pitch (DGG) SN55976A Packaged in a 56-Pin Ceramic Flat Pack (WD) Two Skew Limits Available ESD Protection on Bus Terminals Exceeds 12 kV Low Disabled Supply Current 8 mA Typ Thermal Shutdown Protection Positive- and Negative-Current Limiting Power-Up/Down Glitch Protection
SN75976A DGG or DL SN55976A WD (TOP VIEW)
description
The SN75976A is an improved replacement for 23 34 the industry's first 9-channel RS-485 24 33 transceiver -- the SN75LBC976. The A version 25 32 offers improved switching performance, a smaller 26 31 package, and higher ESD protection. The 27 30 SN75976A is offered in two versions. The '976A2 28 29 skew limits of 4 ns for the differential drivers and 5 ns for the differential receivers complies with the Terminals 13 through 17 and 40 through 44 are recommended skew budget of the Fast-20 SCSI connected together to the package lead frame standard for data transfer rates up to 20 million and signal ground. 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.
GND BSR CRE 1A 1DE/RE 2A 2DE/RE 3A 3DE/RE 4A 4DE/RE VC C GND GND GND GND GND VCC 5A 5DE/RE 6A 6DE/RE 7A 7DE/RE 8A 8DE/RE 9A 9DE/RE
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35
CDE2 CDE1 CDE0 9B+ 9B 8B+ 8B 7B+ 7B 6B+ 6B VCC GND GND GND GND GND VCC 5B+ 5B 4B+ 4B 3B+ 3B 2B+ 2B 1B+ 1B
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.
Copyright © 1997, 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.
POST OFFICE BOX 655303
· DALLAS, TEXAS 75265
1
SN75976A, SN55976A 9-CHANNEL DIFFERENTIAL TRANSCEIVER
SLLS218B MAY 1995 REVISED MAY 1997
description (continued)
In addition to speed improvements, the '976A can withstand electrostatic discharges exceeding 12 kV using the human-body model, and 600 V using the machine model of MIL-PRF-38535, Method 3015.7 on the RS-485 I/O terminals. This is six times the industry standard and provides protection from the noise that can be coupled into external cables. The other terminals of the device can withstand discharges exceeding 4 kV and 400 V respectively. Each of the nine channels of the '976A typically meet or exceed the requirements of EIA RS-485 (1983) and ISO 8482-1987/ TIA TR30.2 referenced by American National Standard of Information (ANSI) Systems, X3.131-1994 (SCSI-2) standard, X2.277-1996 (Fast-20 Parallel Interface), and the Intelligent Peripheral Interface Physical Layer-ANSI X3.129-1986 standard. The SN75976A is characterized for operation over an ambient air temperature range of 0°C to 70°C. The SN55976A is characterized for operation over an ambient air temperature range of 55°C to 125°C.
AVAILABLE OPTIONS Skew Limit (ns) Driver 8 0°C to 70°C to 70°C 4 to 125°C 55°C to 125°C 8 5 9 Receiver 9 TSSOP (DGG) SN75976A1DGG SN75976A1DGGR SN75976A2DGG SN75976A2DGGR -- -- PACKAGE SSOP (DL) SN75976A1DL SN75976A1DLR SN75976A2DL SN75976A2DLR -- -- CERAMIC FLAT PACK (WD) -- -- SN55976A1WD SN55976A2WD
TA
4 5 The R suffix indicates taped and reeled packages.
2
POST OFFICE BOX 655303
· DALLAS, TEXAS 75265
SN75976A, SN55976A 9-CHANNEL DIFFERENTIAL TRANSCEIVER
SLLS218B MAY 1995 REVISED MAY 1997
Terminal Functions
TERMINAL NAME 1A to 9A NO. 4,6,8,10, 19,21,23, 25,27 29,31,33, 35,37,.46, 48,50,52 30,32,34, 36,38,47, 49,51,53 2 Logic Level TTL I/O I/O Termination Pullup DESCRIPTION 1A to 9A carry data to and from the communication controller.
1B to 9B
RS-485
I/O
Pulldown
1B to 9B are the inverted data signals of the balanced pair to/from the bus. 1B+ to 9B+ are the noninverted data signals of the balanced pair to/from the bus. BSR is the bit significant response. BSR disables receivers 1 through 8 and enables wired-OR drivers when BSR and DE/RE and CDE1 or CDE2 are high. Channel 9 is placed in a high-impedance state with BSR high. CDE0 is the common driver enable 0. Its input signal enables all drivers when CDE0 and 1DE/RE 9DE/RE are high. CDE1 is the common driver enable 1. Its input signal enables drivers 1 to 4 when CDE1 is high and BSR is low. CDE2 is the common driver enable 2. When CDE2 is high and BSR is low, drivers 5 to 8 are enabled. CRE is the common receiver enable. When high, CRE disables receiver channels 5 to 9. 1DE/RE9DE/RE are direction controls that transmit data to the bus when it and CDE0 are high. Data is received from the bus when 1DE/RE9DE/RE and CRE and BSR are low and CDE1 and CDE2 are low. GND is the circuit ground. All GND terminals except terminal 1 are physically tied to the die pad for improved thermal conductivity.
1B+ to 9B+
RS-485
I/O
Pullup
BSR
TTL
Input
Pullup
CDE0 CDE1 CDE2 CRE 1DE/RE to 9DE/RE
54 55 56 3 5,7,9,11, 20,22,24, 26,28 1,13,14, 15,16,17, 40,41,42, 43,44 12,18,39, 45
TTL TTL TTL TTL TTL
Input Input Input Input Input
Pulldown Pulldown Pulldown Pullup Pullup
GND
NA
Power
NA
VCC
NA
Power
NA
Supply voltage
Terminal 1 must be connected to signal ground for proper operation.
POST OFFICE BOX 655303
· DALLAS, TEXAS 75265
3
SN75976A, SN55976A 9-CHANNEL DIFFERENTIAL TRANSCEIVER
SLLS218B MAY 1995 REVISED MAY 1997
logic diagram (positive logic)
CDE0 CDE1 BSR 54 55 2
1A
4
30 29
1B+ 1B
1DE/RE
5
2A 2DE/RE 3A 3DE/RE 4A 4DE/RE
6 7 8 9 10 11
Channel 2 Channel 3 Channel 4
32 31 34 33 36 35
2B+ 2B 3B+ 3B 4B+ 4B
CDE2
56
CRE 5A
3 19 38 37 5B+ 5B
5DE/RE
20
6A 6DE/RE 7A 7DE/RE 8A 8DE/RE
21 22 23 24 25 26 2 3 BSR CRE 54
Channel 6 Channel 7 Channel 8
47 46 49 48 51 50
6B+ 6B 7B+ 7B 8B+ 8B
9A 9DE/RE
27 28
BSR
CDE0
53 52
9B+ 9B
4
POST OFFICE BOX 655303
· DALLAS, TEXAS 75265
SN75976A, SN55976A 9-CHANNEL DIFFERENTIAL TRANSCEIVER
SLLS218B MAY 1995 REVISED MAY 1997
schematics of inputs and outputs
DE/RE, CRE, BSR, AND A Inputs 100 k 1 k Input Input 100 k 8V 8V 1 k CDE0, CDE1, AND CDE2 Inputs VCC VCC
B + Input VCC 100 k 16 V Input 18 k Input
B Input VCC
2 k
16 V
2 k 18 k
100 k 4 k 16 V 16 V 4 k
B + AND B Outputs VCC VCC 2 k 16 V 18 k Output 8V 16 V 40 Output A Output
4 k
POST OFFICE BOX 655303
· DALLAS, TEXAS 75265
5
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