4049 current consumption?

[JimRayden]

Well, we all know 4049 is a sucker when it comes to current, right? I'm wondering if the consumption depends on the number of stages in use or is it constant? I'm guessing the first but I wanted to make sure before heading on with the design.

Oh and remind me the current limiting trick too. It was a resistor in series with 9V but what value?

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Jimbo

[twabelljr]

'Hot Harmonics" uses a 200 ohm current limiting resistor, and 3 stages of the 4049.

[gez]

Low(er) supply voltage = battery friendly.

I used to use a Si diode in series with a 3V3 zener to drop supply to 5V, though you need a little RC filter just before the Vdd connection as zeners can introduce noise.   The diode can double as a protection diode for the rest of the circuit if opamps etc are used.  This trick only works if you have at least a few inverter stages (zeners need a certain current draw to do what it says on the tin)

5V regulator is a better approach, though the above is best for current consumption.  ESR and Rapid sell a micropower 5V regulator which I favour (miniscule tick-over current)...can't remember the code...it's not one that trips off the tongue.

Anything under 5V supply just starts sounding bad to me...all subjective though.

Edit:

PS  The more stages the higher the current consumption.  Look at the data sheet for the 4069 and there are curves showing the relationship between current and supply.  Same stuff can be found in the Art of Electronics.  It makes a hell of a difference running things at 5V...no current hogs at this voltage...

[JimRayden]

Thanks gez.

--------
Jimbo

[gez]

The Lama uses a largish resistor from V+ to Vdd pin to drop some of the supply.  From what I gather, this ends up running the chip from around 5V too.

[JimRayden]

The Lama uses a largish resistor from V+ to Vdd pin to drop some of the supply.  From what I gather, this ends up running the chip from around 5V too.

Yea, that was the trick I had in mind. I guess I'll just try resistor values until I reach 5V at the Vcc. If that won't extend bat life, I'll go with zener.

---------
Jimbo

[puretube]

Mark had a nice "sag" proposal with a current regulator by *forgot the name* (sorry)...

[MartyMart]

I'm just doing the exact same thing, I have a 4049 based circuit using a
J201 to boost the front end and two stages on the 4049.
At first had a 200Ohm R from 9v, so pin 1 was getting around 8.4 v
This was sounding good but very "tight" and a little "splatty" when the gain
was lowered.
I used a 5v6 zener to pin 1 and removed the 100 Ohm resistor.
I now have about 4 volts to the chip and it sounds fantastic !!
Much more "loose" and amp sounding, with no loss of gain or volume, infact
there seems to be more breakup with this voltage "sag" on the 4049
The sound is hard to decribe, loose and floppy is as close as I can get !

Worth a try for sure, it's got it's own "voice" now which I love

MM

[Mark Hammer]

Mark had a nice "sag" proposal with a current regulator by *forgot the name* (sorry)...

That would be this article and design by the late Charles R. Fischer, using an LM334Z current regulator for the 4049 chip specifically. http://www.generalguitargadgets.com/index.php?option=content&task=view&id=174&Itemid=200

[gez]

I'm just doing the exact same thing, I have a 4049 based circuit using a
J201 to boost the front end and two stages on the 4049.

One thing to bear in mind with lower supplies to the chip and an input stage that is powered from full supply, is it's easier to bring the protective diodes of the inverter chip into conduction when AC coupled, though whether this occurs all depends on how hot the driving stage is.  If you've used an input resistor to the 1st inverter (most designs do) it's unlikely you'll fry the chip or anything, but if you're decoupling AC feedback it's best to include a protection resistor on the input.

PS  The gain of inverters actually increases as supply lowers so this, in conjunction with reduced headroom, would give you more distortion...nice isn't it?! 

[MartyMart]

Thanks Gez, as with 'all' my cmos circuits, there is a "quirk" which occurs
at both 8v and 4v to the 4049.
Higher gain settings are fine and dandy, but lower gain produces a hard and splatty
crunch, even with pups rolled down a lot.
Seems like its only a "high gainer"  !!
Unless i need to back off the Fetzer valve up the front perhaps ?
( have a 150 reverse log pot between fetzer and first cmos stage )

MM.

[gez]

Higher gain settings are fine and dandy, but lower gain produces a hard and splatty crunch, even with pups rolled down a lot.

Try 3 stages and reduce the gain a little in each.

[JimRayden]

Higher gain settings are fine and dandy, but lower gain produces a hard and splatty crunch, even with pups rolled down a lot.

Try 3 stages and reduce the gain a little in each.

This brings me to my other question, for which I haven't noticed an answer. Does current draw depend on the number of stages used? Or, how much does it change?

----------
Jimbo

[gez]

Answer was above Jim - "PS  The more stages the higher the current consumption.  Look at the data sheet for the 4069 and there are curves showing the relationship between current and supply.  Same stuff can be found in the Art of Electronics"

Check pages 6 & 7 in this data sheet to give you a rough idea of figures (data sheet is BS compatible):

http://www.matrixrunner.net/pdf/hef4069.pdf