SN75LBC970A Datasheet | Texas Instruments

description The SN75LBC970A SCSI differential convertercontrol is an adaptation of the industry’s first 9-channel RS-485 transceiver, the SN75LBC976. When used in conjunction with one or more of its panion data transceiver(s), SN75LBC971A, the chip set provides the superior electrical performance of differential SCSI from a single-ended SCSI bus 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) and a few external ponents. GND GND GND VCC DRVBUS SDB AMSG - AI/O - ASEL- NC ABSY - NC ARST - NC 15 16 17 18 19 20 21 22 23 24 25 26 27 28 42 GND 41 GND 40 GND 39 VCC 38 BMSG - 37 BMSG+ 36 BI/O - 35 BI/O+ 34 BSEL+ 33 BSEL - 32 BBSY+ 31 BBSY - 30 BRST+ 29 BRST - In a typical differential SCSI node, the SCSI controller provides the enables for each external - no internal connection RS-485 transceiver. This could require as many as 27 additional terminals for a 16-bit differential bus controller or relegate a 16-bit single-ended Terminals 13 through 17 and 40 through 44 are connected together to the package lead frame and signal ground. controller to only an 8-bit differential bus. Using the standard nine SCSI control signals, the SN75LBC970A control transceiver decodes the state of the bus and enables the SN75LBC971A 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...