SN54ABT16821, SN74ABT16821

20-BIT BUS-INTERFACE FLIP-FLOPS

WITH 3-STATE OUTPUTS

SCBS216B – JUNE 1992 – REVISED JANUARY 1997

1

POST OFFICE BOX 655303

Widebus

™ Family

Significantly Reduces Power Dissipation

MIL-STD-883, Method 3015; Exceeds 200 V

Using Machine Model (C = 200 pF, R = 0)

Minimizes High-Speed Switching Noise

Layout

Shrink Small-Outline (DGG), 300-mil Shrink

Small-Outline (DL) Packages and 380-mil

Fine-Pitch Ceramic Flat (WD) Package

Using 25-mil Center-to-Center Spacings

description

These 20-bit flip-flops feature 3-state outputs

designed specifically for driving highly capacitive

or relatively low-impedance loads. They are

particularly suitable for implementing wider buffer

registers, I/O ports, bidirectional bus drivers with

parity, and working registers.

The ’ABT16821 can be used as two 10-bit

flip-flops or one 20-bit flip-flop. The 20 flip-flops

are edge-triggered D-type flip-flops. On the

positive transition of the clock (CLK) input, the

device provides true data at the Q outputs.

A buffered output-enable (OE) input can be used to place the ten outputs in either a normal logic state (high

or low logic level) or a high-impedance state. In the high-impedance state, the outputs neither load nor drive

the bus lines significantly. The high-impedance state and increased drive provide the capability to drive bus lines

without need for interface or pullup components.

OE does not affect the internal operation of the flip-flops. Old data can be retained or new data can be entered

while the outputs are in the high-impedance state.

resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

The SN54ABT16821 is characterized for operation over the full military temperature range of –55

°C to 125°C.

The SN74ABT16821 is characterized for operation from –40

°C to 85°C.

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.

Widebus and EPIC-

ΙΙB are trademarks of Texas Instruments Incorporated.

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.

SN54ABT16821 . . . WD PACKAGE

SN74ABT16821 . . . DGG OR DL PACKAGE

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1OE

1Q1

1Q2

GND

1Q3

1Q4

1Q5

1Q6

1Q7

GND

1Q8

1Q9

1Q10

2Q1

2Q2

2Q3

GND

2Q4

2Q5

2Q6

2Q7

2Q8

GND

2Q9

2Q10

2OE

1CLK

1D1

1D2

GND

1D3

1D4

1D5

1D6

1D7

GND

1D8

1D9

1D10

2D1

2D2

2D3

GND

2D4

2D5

2D6

2D7

2D8

GND

2D9

2D10

2CLK