• State-of-the-Art BiCMOS Design
Significantly Reduces ICCZ
• ESD Protection Exceeds 2000 V Per
MIL-STD-883C, Method 3015; Exceeds
200 V Using Machine Model (C = 200 pF,
R = 0)
• Latch Version of the ′BCT646
• Independent Latches and Enables for
A and B Buses
• Multiplexed Real-Time and Stored Data
• Package Options Include Plastic
Small-Outline (DW) Packages and Standard
Plastic 300-mil DIPs (NT)
OCTAL BUS TRANSCEIVER AND LATCH
WITH 3ĆSTATE OUTPUTS
SCBS088A − NOVEMBER 1991 − REVISED NOVEMBER 1993
DW OR NT PACKAGE
The SN74BCT956 consists of bus transceiver circuits, D-type latches, and control circuitry arranged for
multiplexed transmission of data directly from the input bus or from the internal latches. Data on the A or B bus
is stored in the latches when the appropriate latch-enable (LEAB or LEBA) input is low. Figure 1 illustrates the
four fundamental bus-management functions that can be performed with the SN74BCT956.
Output-enable (OE) and direction-control (DIR) inputs are provided to control the transceiver functions. In the
transceiver mode (OE low), data present at the high-impedance port may be stored in either latch or in both.
The select-control (SAB and SBA) inputs can multiplex stored and real-time (transparent mode) data. When the
appropriate latch-enable input is high, the latch is transparent, and real-time data is output regardless of the level
at the select control.
The direction control (DIR) determines which bus receives data when OE is low. In the isolation mode (OE high),
A data may be stored in one register and/or B data may be stored in the other register.
When an output function is disabled, the input function is still enabled and may be used to store and transmit
data. Only one of the two buses, A or B, may be driven at a time.
The SN74BCT956 is characterized for operation from 0°C to 70°C.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright 1993, Texas Instruments Incorporated
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