SN75971B Datasheet | Texas Instruments

description GND 14 GND 15 43 GND 42 GND The SN75971B SCSI differential converter-data is a 9-channel RS-485 transceiver. When used in conjunction with its panion control transceiver, the SN75970B, the resulting chip set provides the superior electrical performance of differential SCSI from a single-ended SCSI bus or controller. A 16-bit Ultra-SCSI (or Fast-20) SCSI bus can be implemented GND 16 GND 17 VCC 18 ABD4 - 19 NC 20 ADB3 - 21 NC 22 41 GND 40 GND 39 VCC 38 BDB4 - 37 BDB4 + 36 BDB3 - 35 BDB3 + with just three devices (two data and one control) in the ADB2 - 23 34 BDB2 - space efficient, 56-pin, shrink small-outline package NC 24 33 BDB2 + (SSOP) or thin shink small outline package (TSSOP) ADB1 - 25 32 BDB1 - and a few external ponents. An 8-bit SCSI bus NC 26 31 BDB1 + requires only one data and one control transceiver. ADB0 - 27 30 BDB0 - The SN75971B is available in a B2 (20 Mxfer) NC 28 29 BDB0 + version and a B1 (10 Mxfer) version. Pins 13 - 17 and 40 - 44 are connected In a typical differential SCSI node, the SCSI controller provides an enable for each external RS-485 transceiver channel. This could require as many as 27 together to the package lead frame and to signal ground. NC - No internal connection extra terminals for a 16-bit differential bus controller or relegate a 16-bit, single-ended controller to only an 8-bit differential bus. Using the standard nine SCSIcontrol signals, the SN75970B control transceiver decodes the state of the bus and enables the SN75971B data transceiver to transmit the single-ended SCSI input signals (A side) differentially to the cable or receive the differential cable signals (B side) and drive the single-ended outputs to the controller. A reset function, which disables all outputs and clears internal latches, can be acplished from two external inputs and two internally-generated signals. RESET (reset) and DSENS (differential sense) are available to external circuits for a bus reset or to...