SN75LBC971A Datasheet | Texas Instruments

description GND 14 GND 15 43 GND 42 GND The SN75LBC971A SCSI differential converter-data is GND 16 41 GND an adaptation of the industry’s first 9-channel RS-485 GND 17 40 GND transceiver, the SN75LBC976. When used in conjunction with its panion control transceiver, the VCC 18 ABD4 - 19 39 VCC 38 BDB4 - SN75LBC970A, the resulting chip set provides the NC 20 37 BDB4 + superior electrical performance of differential SCSI from a single-ended SCSI bus or controller. A 16-bit SCSI bus can be implemented with just three devices (two data and one control) in the space efficient, 56-pin, shrink small-outline package (SSOP) and a few external ponents. An 8-bit SCSI bus requires only one data and one control transceiver. ADB3 - NC ADB2 - NC ADB1 - NC ADB0 - 21 22 23 24 25 26 27 36 BDB3 - 35 BDB3 + 34 BDB2 - 33 BDB2 + 32 BDB1 - 31 BDB1 + 30 BDB0 - In a typical differential SCSI node, the SCSI controller NC 28 29 BDB0 + provides an enable for each external RS-485 transceiver channel. This could require as many as 27 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 SCSI Pins 13 - 17 and 40 - 44 are connected together to the package lead frame and to signal ground. NC - No internal connection control signals, the SN75LBC970A control transceiver decodes the state of the bus and enables the SN75LBC971A 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 disable all outputs should a single-ended cable be inadvertently connected to a differential...