SN75970B Datasheet | Texas Instruments

description GND 15 GND 16 42 GND 41 GND The SN75970B SCSI differential converter- GND 17 40 GND control, when used in conjunction with one or more of its panion data transceiver(s), VCC 18 DRVBUS 19 39 VCC 38 BMSG - provides the superior electrical performance of SDB 20 37 BMSG+ differential SCSI from a single-ended SCSI bus AMSG - 21 36 BI/O - controller. A 16-bit, Fast-SCSI bus can be implemented with just three devices (two for data and one for control) in the space-efficient, 56-pin, shrink small-outline package (SSOP) as well as the even smaller TSSOP and a few external ponents. AI/O - ASEL- NC ABSY - NC ARST - 22 23 24 25 26 27 35 BI/O+ 34 BSEL+ 33 BSEL - 32 BBSY+ 31 BBSY - 30 BRST+ The SN75970B is available in a B2 (20 Mxfer) NC 28 29 BRST - version and a B1 (10 Mxfer) version. In a typical differential SCSI node, the SCSI controller provides the enables for each external RS-485 transceiver. This could require as many - No internal connection Terminals 13 through 17 and 40 through 44 are connected together to the package lead frame and signal ground. as 27 additional 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 SCSI control signals, the SN75970B control transceiver decodes the state of the bus and enables the SN75971B data transceiver(s) to transmit the single-ended SCSI input signals differentially to the cable or receive the differential cable signals and drive the single-ended outputs to the controller. The single-ended SCSI bus interface consists of CMOS bidirectional inputs and outputs. The drivers are rated at ±16 m A of output current. The receiver inputs are pulled high with approximately 4 m A to eliminate the need for external pullup resistors for the open-drain outputs of most single-ended SCSI controllers. The single-ended side of the device is not intended to drive the SCSI bus directly. Please be aware that an...