4017 guestion

[bcroe at juno.com]

The 4000 series has survived 3 decades cause of some good
stuff.  3 to 15 volt operation, great noise margin, little EMI,
negligible
(almost unmeasureable) power, rail to rail swing (for those into 
analog stuff), practically infinite input impedance, and ability to 
directly control a big honking FET.  But output drive is limited.  For
the common "B" series at temp we see
VCC      output  current
 5V          0.36 ma
10V         0.9  ma
15V          2.4ma

Putting a 4049B/4050B buffer will give you 6 times those 
numbers.  If you're running Vcc between 3 and 5 volts, you can 
use an HC or AC CMOS buffer to get more current.  That voltage
won't drive the original FETs, but some newer "L" logic FETs 
are intended to be compatible with a 5 volt supply.

Bruce Roe

On Mon, 18 Feb 2002 23:48:26 -0800 "944Technologist" <f_wilk at hotmail.com>
writes:
> A 4017B will source between 1ma & 2ma so get a low current LED.
> 
> FR Wilk

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