V62/08614-01XE

The SN75976A is an improved replacement for the industry’s first 9-channel 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.

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 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 –55°C to 125°C.

Key Features

• Controlled Baseline
  • One Assembly Site
  • One Test Site
  • One Fabrication Site
• Extended Temperature Performance of –55°C to 125°C
• Enhanced Diminishing Manufacturing Sources (DMS) Support
• Enhanced Product-Change Notification
• Qualification Pedigree⁽¹⁾
• 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 Thin Shrink Small-Outline Package with 20-Mil Terminal Pitch (DGG)
• Two Skew Limits Available
• ESD Protection on Bus Terminals Exceeds
  12 kV
• Low Disabled Supply Current 8 mA Typical
• Thermal Shutdown Protection
• Positive and Negative Current Limiting
• Power-Up/Down Glitch Protection

⁽¹⁾ Component qualification in accordance with JEDEC and industry standards to ensure reliable operation over an extended temperature range. This includes, but is not limited to, Highly Accelerated Stress Test (HAST) or biased 85/85, temperature cycle, autoclave or unbiased HAST, electromigration, bond intermetallic life, and mold compound life. Such qualification testing should not be viewed as justifying use of this component beyond specified
performance and environmental limits.