SN54ABT16657, SN74ABT16657
16-BIT TRANSCEIVERS WITH PARITY GENERATORS/CHECKERS
AND 3-STATE OUTPUTS

SCBS103B – FEBRUARY 1992 – REVISED JANUARY 1997
1POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
C0068 Members of the Texas Instruments
Widebus Family
C0068 State-of-the-Art EPIC-II B BiCMOS Design
Significantly Reduces Power Dissipation
C0068 Latch-Up Performance Exceeds 500 mA Per
JEDEC Standard JESD-17
C0068 Typical V
OLP
(Output Ground Bounce) < 1 V
at V
CC
= 5 V, T
A
= 25°C
C0068 Distributed V
CC
and GND Pin Configuration
Minimizes High-Speed Switching Noise
C0068 Flow-Through Architecture Optimizes PCB
Layout
C0068 High-Drive Outputs (–32-mA I
OH
, 64-mA I
OL
)
C0068 Package Options Include Plastic 300-mil
Shrink Small-Outline (DL) and Thin Shrink
Small-Outline (DGG) Packages and 380-mil
Fine-Pitch Ceramic Flat (WD) Package
Using 25-mil Center-to-Center Spacings
description
The ’ABT16657 contain two noninverting octal
transceiver sections with separate parity
generator/checker circuits and control signals.
For either section, the transmit/receive (1T/R or
2T/R) input determines the direction of data flow.
When 1T/R (or 2T/R) is high, data flows from the
1A (or 2A) port to the 1B (or 2B) port (transmit
mode); when 1T/R (or 2T/R) is low, data flows
from the 1B (or 2B) port to the 1A (or 2A) port
(receive mode). When the output-enable (1OE or
2OE) input is high, both the 1A (or 2A) and 1B (or
2B) ports are in the high-impedance state.
Odd or even parity is selected by a logic high or low level, respectively, on the 1ODD/EVEN (or 2ODD/EVEN)
input. 1PARITY (or 2PARITY) carries the parity bit value; it is an output from the parity generator/checker in the
transmit mode and an input to the parity generator/checker in the receive mode.
In the transmit mode, after the 1A (or 2A) bus is polled to determine the number of high bits, 1PARITY (or
2PARITY) is set to the logic level that maintains the parity sense selected by the level at the 1ODD/EVEN (or
2ODD/EVEN) input. For example, if 1ODD/EVEN is low (even parity selected) and there are five high bits on
the 1A bus, then 1PARITY is set to the logic high level so that an even number of the nine total bits (eight 1A-bus
bits plus parity bit) are high.
Copyright  1997, Texas Instruments Incorporated
UNLESS OTHERWISE NOTED this document contains PRODUCTION
DATA information 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.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Widebus and EPIC-II B are trademarks of Texas Instruments Incorporated.
SN54ABT16657 . . . WD PACKAGE
SN74ABT16657 . . . DGG OR DL PACKAGE
(TOP VIEW)
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1OE
NC
1ERR
GND
1A1
1A2
V
CC
1A3
1A4
1A5
GND
1A6
1A7
1A8
2A1
2A2
2A3
GND
2A4
2A5
2A6
V
CC
2A7
2A8
GND
2ERR
NC
2OE
1T/R
1ODD/EVEN
1PARITY
GND
1B1
1B2
V
CC
1B3
1B4
1B5
GND
1B6
1B7
1B8
2B1
2B2
2B3
GND
2B4
2B5
2B6
V
CC
2B7
2B8
GND
2PARITY
2ODD/EVEN
2T/R
NC – No internal connection