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Need info on vintage General Instrument Mosfets

Discussion in 'Electronic Components' started by wa2rqy, Nov 26, 2008.

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  1. wa2rqy

    wa2rqy Guest

    Hi All;
    I got a bunch of these older GI Mosfets but really was not able to
    find much info on the WWW.
    Any info would be helpful.
    I think they are from around 1976 or so and in plastic boxes marked:
    They were part of an Electronic Engineers stash of samples I guess?
  2. legg

    legg Guest

    1976 is quite early for these devices to be power mosfets. IR and
    Hitachi only started commercialization around that time. Are these
    date-coded? Are you sure you've read the logo correctly? What case
    size (TO3 metal most common, at that time)

    There were a lot of mosfet fabs that fell afoul of IR's patents in
    this period.
    GI did have power mosfets (Y-MOS)listed in their '86 catalog, which
    disappeared from the '87 catalog (after GI absorbed Varo).

    Part numbers were constructed

    P - Mosfet
    A,B, C - 60, 100 or 150V - Vds
    XXX - power rating in watts
    N - n-chanel
    xxx - Rdson in milliohms
    L,S,H - 0.8, 2.0, 4.0 - threshold voltage
    P,M,T - To218/to247, to3, to220 package.

    So a typical part was PA125N40SM

  3. Phil Allison

    Phil Allison Guest


    ** According to my transistor /fet data book from1976, all the above are P
    channel junction fets in TO72 cases.

    Vds = 25 to 60 volts, Pd = 125 to 200 mW

    ** Dunno - but more likely a mosfet.

    ....... Phil
  4. wa2rqy

    wa2rqy Guest

    Great, thanks Phil:)
    I knew I cud count on you guys!
  5. Phil Allison

    Phil Allison Guest

    "Phil Allison"

    ** Do you want the rest of the data on the first three ?

    ..... Phil
  6. legg

    legg Guest

    Towers shows
    MEM520 - 30V 50mA 250ohm PMOS-enhancement mode rf switch (2.5pF Ciss),
    MEM556 - 80V 20mA ~same (0.5pF Ciss). Both in TO72
    MEM554 - 20V NMOS dual-gate low frequency amplifier.

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