SN75971B1DL

Drivers, Receivers, Transceivers Overview

The SN75971B1DL is a 9-channel RS-485 transceiver designed for SCSI differential data conversion. It operates with a supply voltage range of 4.75 V to 5.25 V and supports data transfer rates up to 10 Mxfer. The device features bidirectional single-ended inputs/outputs rated at ±16 mA and bipolar differential I/Os meeting EIA-485 standards. Electrical characteristics include a typical disabled supply current of 32 mA, propagation delays ranging from 4 ns to 12.9 ns depending on direction and temperature, and receiver input hysteresis of 35 mV to 45 mV. It is housed in a 56-pin SSOP package.

Drivers, Receivers, Transceivers Feature Summary

• Provides high-voltage differential SCSI conversion from single-ended controllers when paired with the SN75970B control transceiver.
• Includes thermal shutdown protection and positive/negative current limiting for enhanced reliability.
• Features open-circuit failsafe receivers and power-up/down glitch protection.
• Offers internal latch circuits for independent direction control of each data bit.

Drivers, Receivers, Transceivers Applications

• Implementing 16-bit Ultra-SCSI (Fast-20) buses using three devices.
• Converting 8-bit single-ended SCSI bus signals to differential formats.
• Connecting single-ended SCSI controllers to differential SCSI cables.

Drivers, Receivers, Transceivers Procurement Notes

Verify the specific B1 suffix indicates the 10 Mxfer speed grade during procurement. Confirm the DL package designation corresponds to the shrink small-outline package with 25 mil terminal pitch. Ensure compatibility with the required 5 V supply voltage and check for RoHS compliance status if environmental regulations apply to the manufacturing process.

Drivers, Receivers, Transceivers Selection Notes

Select this component when interfacing single-ended SCSI controllers with differential SCSI buses requiring 9 channels of data and parity conversion. The B1 variant is suitable for systems operating at speeds up to 10 Mxfer. Consider the SN75970B as the necessary companion control transceiver to manage bus direction and enable signals effectively.

Drivers, Receivers, Transceivers Part Context

The SN75971B series consists of two speed grades: the B1 version supporting 10 Mxfer and the B2 version supporting 20 Mxfer. Both variants share identical pinouts and functional descriptions but differ in switching characteristics. This part belongs to the SCSI differential converter family, specifically designated for data transmission rather than control signal handling.

Drivers, Receivers, Transceivers Replacement Considerations

The SN75971B2DL serves as a higher-speed alternative within the same family, offering 20 Mxfer performance while maintaining electrical compatibility. Other similar parts include the SN75LBC971A, which provides comparable SCSI differential data conversion capabilities.

Drivers, Receivers, Transceivers FAQ

How does the SN75971B determine data direction?

Direction is controlled by the DRVBUS and SDB inputs. When DRVBUS is low, a bidirectional latch sets the direction based on asserted inputs. When DRVBUS is high, the SDB signal determines the flow between the differential and single-ended sides.

What is the purpose of the DSENS and RESET pins?

Both DSENS and RESET are TTL-level inputs that initialize internal latches and disable all drivers when held low. They provide external control for bus resets or to disable outputs if an incorrect cable connection is detected.

Does the device perform parity checking?

No, the SN75971B does not perform parity checking. The parity signal passes through the device transparently, functioning identically to the other eight data bits.