[sdiy] CMOS 4000 series, B or UB

[harrybissell]

Actually, CMOS was available in "A" or "B" series.
B is the buffered aprts are are more common, and preferred
for almost EVERY application except linear ones.

The "A" series parts have largely disappeared... except for
the 4049 and 4069 which are 'UB" (unbuffered)

The trouble with A series parts is that the threshold voltages
varied with the number of inputs high... So a three input gate could
respond
differently if one input went high, or if two went high, or three... 

The "B" series is almost totally independant of logic states on
threshold
voltage (as a good logic family should be).  There is a slight penalty
in propagation delay in the "B" series.

In most cases "A" and "B" can be swapped, except in linear circuits

H^) harry

Andre Majorel wrote:
> 
> Folks, is this a correct summary of the situation ?
> 
> All CMOS 4000 series chips are buffered (B) except :
> 
>   4000 dual 3-input NOR gate and inverter       (usually B but UB exists)
>   4001 quad 2-input NOR gate                    (B/UB)
>   4002 dual 4-input NOR gate                    (usually B but UB exists)
>   4007 dual complementary pair and inverter     (UB only)
>   4009 hex inverter                             (B/UB)
>   4010 hex buffer                               (usually B but UB exists)
>   4011 quad 2-input NAND gate                   (B/UB)
>   4012 dual 4-input NAND gate                   (usually B but UB exists)
>   4030 quad XOR gate                            (usually B but UB exists)
>   4041 quad true/complement buffer              (usually B but UB exists)
>   4049 hex inverter                             (B/UB)
>   4069 hex inverter                             (UB only)
> 
> Plus 4023 and 4025 where the function and bufferedness are
> dependent variables :
> 
>   4023UB triple 3-input NOR gate                (uncommon)
>   4023B  triple 3-input NAND gate
>   4025UB triple 3-input NAND gate               (uncommon)
>   4025B  triple 3-input NOR gate
> 
> Thanks.
> 
> --
> André Majorel <amajorel at teaser.fr>
> http://www.teaser.fr/~amajorel/