________________________________________________________________________________

MODEL:  std20.vhd                                                VERSION:    1.0
DESCRIPTION:  4-input positive-NAND gate                         DATE: 99 AUG 19
TIMING FILE:  std20.ftm                                          VERSION:    1.0
                                                                 DATE: 00 DEC 03
LOCATION:  http://www.FreeModelFoundry.com/fmf_models/std/std20.vhd
LOCATION:  http://www.FreeModelFoundry.com/fmf_models/std/std20.ftm

LIBRARY:  STND

GENERIC PART NUMBERS COVERED:  7420, 74AC20, 74ALS20A, 74AS20, 74HC20, 74LS20,
                               74S20, 74VHC20

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SUPPORTED PART NUMBERS
    ____________________________________________________________________________

                   Fairchild Semiconductor 

    Part Number                       Data Source
    ____________________________________________________________________________

    74AC20PC_3V3                           1

    74AC20MTC_3V3                          1

    74AC20SC_3V3                           1

    74AC20SJ_3V3                           1

    74AC20PC_5V                            1

    74AC20MTC_5V                           1

    74AC20SC_5V                            1

    74AC20SJ_5V                            1

    ____________________________________________________________________________

                   National Semiconductor

    Part Number                       Data Source
    ____________________________________________________________________________

    DM74LS20M                              2

    DM74LS20N                              2

    DM74S20N                               2

    ____________________________________________________________________________

                   Texas Instruments       

    Part Number                       Data Source
    ____________________________________________________________________________

    SN7420N                                3

    SN74ALS20AD                            4

    SN74ALS20AN                            4

    SN74AS20AD                             4

    SN74AS20AN                             4

    SN74HC20D                              5

    SN74HC20N                              5

    SN74HC20NS                             5

    SN74LS20D                              4

    SN74LS20N                              4

    SN74LS20NS                             4

    SN74S20D                               4

    SN74S20N                               4

    ____________________________________________________________________________

                   Toshiba

    Part Number                       Data Source
    ____________________________________________________________________________

    TC74VHC20F_5V                          6

    TC74VHC20FN_5V                         6

    TC74VHC20FS_5V                         6

    TC74VHC20FT_5V                         6


________________________________________________________________________________

DATA SOURCES

    These are the primary sources of data used in determining behaviour and 
    timing of the components represented by this model.

    1.   Fairchild Semiconductor DS009918-Revised November 1999

    2.   National Semiconductor 400044 1989

    3.   Texas Instruments SDLS079-Revised March 1988

    4.   Texas Instruments SDAS192B-Revised December 1994

    5.   Texas Instruments SCLS086D-Revised February 2000

    6.   Toshiba 961001EBA2 1997-01-30