SN54AS866, SN74AS866A

8BIT MAGNITUDE COMPARATORS

SDAS183A − DECEMBER 1982 − REVISED JUNE 1990

POST OFFICE BOX 655303

POST OFFICE BOX 1443

Copyright

1

Outline Packages, Both Plastic and Ceramic

Chip Carriers, and Standard Plastic and

Ceramic DIPs

Enables

description

These Advanced Schottky devices are capable of

performing

high-speed

arithmetic

or

logical

comparisons on two 8-bit binary or two’s

complement

words.

Three

fully

decoded

decisions about words P and Q are externally

available at the outputs. These devices are fully

expandable to any word length by connecting the

totem pole P>Q and P<Q outputs of each stage to

the P>Q and P<Q inputs of the next higher-order

stage. The cascading paths are implemented with

only a two-gate-level delay to reduce overall

comparison times for long words.

The open-

collector P=Q output may be wire-ANDed

together.

Both input words P and Q plus all three outputs

(P>Q, P<Q, and P = Q) are equipped with latches

to provide the designer with temporary data

storage for avoiding race conditions. The enable

circuitry is implemented with minimal delay times

to enhance performance when the devices are

cascaded for longer word lengths. Each latch is

transparent when the appropriate latch enable,

PLE, QLE, or OLE is high.

The enable inputs PLE and QLE and data inputs

P and Q utilize pnp input transistors to reduce the

low-level input current requirement to typically

−0.25 mA, which minimizes loading effects.

The Q register may be cleared to zero for a fast comparison of the P word to zero.

The SN54AS866 is characterized for operation over the full military temperature range of −55

°C to 125°C. The

SN74AS866A is characterized for operation from 0

°C to 70°C.

SN54AS866 ...JD PACKAGE

SN74AS866A ...N PACKAGE

(TOP VIEW)

SN54AS866 . . . FK PACKAGE

SN74AS866A . . . FN PACKAGE

(TOP VIEW)

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QLE

L/A

p < Qin

P > Qin

Q7

Q6

Q5

Q4

Q3

Q2

Q1

Q0

P = Qout

GND

CLRQ

PLE

P7

P6

P5

P4

P3

P2

P1

P0

P < Qout

P > Qout

OLE

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13 14

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P7

P6

P5

P4

P3

P2

P1

Q7

Q6

Q5

Q4

Q3

Q2

Q1

4

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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.