Maker Pro
Maker Pro

FREE MC4024's

T

Tim Shoppa

Jan 1, 1970
0
I just found a Metric Buttload of MC4024's (1978/1979 date codes). Mostly
MC4024P plastic DIP packages, a few MC4024L ceramic DIP packages. Found
the datasheet on Jim Thompson's website, stuck
one on a breadboard, hooked up a scope, and watched it do its stuff as
I tweaked Vin. Other than that, doesn't seem too awfully exciting.
(No offense, Jim, just that it's hard for me to get excited over a
15MHz VCO without a built-in phase detector).

I think I got these some years ago to use as VCO's in PLL data separators
for disk data (5MHz MFM, or maybe even 250/500kHz 8" floppy stuff). Probably
with tapped ring counters to do the "counting" and decoding.

Anyone interested in a few or a bunch of 'em for free? If so, drop me an
E-mail with "MC4024" in the subject and requested quantity and
your name and shipping address. I reserve the right to prioritize
sending them out, after all I'm paying for postage... US recipients will
probably come first just because of less paperwork/postage hassle.

Tim.
 
J

Jim Thompson

Jan 1, 1970
0
I just found a Metric Buttload of MC4024's (1978/1979 date codes). Mostly
MC4024P plastic DIP packages, a few MC4024L ceramic DIP packages. Found
the datasheet on Jim Thompson's website, stuck
one on a breadboard, hooked up a scope, and watched it do its stuff as
I tweaked Vin. Other than that, doesn't seem too awfully exciting.
(No offense, Jim, just that it's hard for me to get excited over a
15MHz VCO without a built-in phase detector).
[snip]

Considering that I designed it ~1968 it's not too shabby. The
matching PFD is the MC4044.

The MC4024 core structure was also fabricated on MECL III and will do
~300MHz.

Other of my PLL designs are now made in the 12000 series.

...Jim Thompson
 
T

Tim Shoppa

Jan 1, 1970
0
Jim Thompson said:
Considering that I designed it ~1968 it's not too shabby. The
matching PFD is the MC4044.

The MC4024 core structure was also fabricated on MECL III and will do
~300MHz.

Other of my PLL designs are now made in the 12000 series.

As long as we're on the subject, have you ever posted a schematic of
the MC1648 or discussed the AGC mechanism it uses?

Tim.
 
J

Jim Thompson

Jan 1, 1970
0
As long as we're on the subject, have you ever posted a schematic of
the MC1648 or discussed the AGC mechanism it uses?

Tim.

No I haven't, but it looks like I should... the publicized schematic
seems to be with errors.

When I have some free time (I'm up to my ears in work right now), I'll
post a description of how it works.

...Jim Thompson
 
L

Leon Heller

Jan 1, 1970
0
Jim Thompson said:
No I haven't, but it looks like I should... the publicized schematic
seems to be with errors.

When I have some free time (I'm up to my ears in work right now), I'll
post a description of how it works.

I've played about with two transistors in the same oscillator circuit (from
AoE) but couldn't get anything like a sine wave out of them. I suppose that
is achieved via the AGC.

Leon
 
T

Tim Shoppa

Jan 1, 1970
0
Jim Thompson said:
No I haven't, but it looks like I should... the publicized schematic
seems to be with errors.

When I have some free time (I'm up to my ears in work right now), I'll
post a description of how it works.

Casting about via Google I eventually found a datasheet:

http://www.dafh.org/gbppr/lpfm/Mc1648.pdf

My understanding is that AGC gain is set by varying the current through
Q6/Q7's emitter-coupled tail. What confuses me at the moment is how
VEE actually goes to the base of Q8 and the whole "bottom line"
of the schematic, which I would expect to be Vee, seems to be modulated
by AGC (maybe that should be thought of as the AGC line?)

I *think* this would really limit the swing range of everything,
which seems to be a bad thing for good spectral purity.

Is one of the mistakes in the schematic that pin 8 (V_EE) really deserves
a dot to the bottom line? Or should I think of that as what the AGC
actually modulates?

Tim.
 
J

Jim Thompson

Jan 1, 1970
0
Jim Thompson said:
On 24 Oct 2004 16:23:13 -0700, [email protected] (Tim Shoppa)
wrote: [snip]
As long as we're on the subject, have you ever posted a schematic of
the MC1648 or discussed the AGC mechanism it uses?

Tim.

No I haven't, but it looks like I should... the publicized schematic
seems to be with errors.

When I have some free time (I'm up to my ears in work right now), I'll
post a description of how it works.

I've played about with two transistors in the same oscillator circuit (from
AoE) but couldn't get anything like a sine wave out of them. I suppose that
is achieved via the AGC.

Leon

What page of AoE? It's pretty hard to not get a sine wave when you
use a tank, you just get a far better noise floor when you use AGC
(rather than limiting) to control amplitude.

...Jim Thompson
 
J

Jim Thompson

Jan 1, 1970
0
Casting about via Google I eventually found a datasheet:

http://www.dafh.org/gbppr/lpfm/Mc1648.pdf

My understanding is that AGC gain is set by varying the current through
Q6/Q7's emitter-coupled tail. What confuses me at the moment is how
VEE actually goes to the base of Q8 and the whole "bottom line"
of the schematic, which I would expect to be Vee, seems to be modulated
by AGC (maybe that should be thought of as the AGC line?)

I *think* this would really limit the swing range of everything,
which seems to be a bad thing for good spectral purity.

Is one of the mistakes in the schematic that pin 8 (V_EE) really deserves
a dot to the bottom line? Or should I think of that as what the AGC
actually modulates?

Tim.

Both VEEs lack a dot. See my patent for an explanation.

...Jim Thompson
 
W

Winfield Hill

Jan 1, 1970
0
Jim Thompson wrote...
Both VEEs lack a dot. See my patent for an explanation.

Number? Or is it on your web-site?
 
J

Jim Thompson

Jan 1, 1970
0
Jim Thompson wrote...

Number? Or is it on your web-site?

3,644,835 Phase Detector and Digital Phase-Locked Loop - Analog Phase
Detector with "Howland" current mirror load - Military Application

3,649,929 Sine and Square-Wave Oscillator with AGC - MC1648

3,665,343 Voltage Controlled Multivibrator - MC4024/MC1658 and
variants

Full patent list on website.

...Jim Thompson
 
I assume this is NOT the 4024 CMOS chip? I am in desperate need of some 4024s
in the metal can package (they are no longer made).
 
J

Jim Thompson

Jan 1, 1970
0
I assume this is NOT the 4024 CMOS chip? I am in desperate need of some 4024s
in the metal can package (they are no longer made).
[snip]

Isn't the CMOS 4024 a counter and NOT a VCM (voltage-controlled
multivibrator), which the MC4024 is?

...Jim Thompson
 
W

Winfield Hill

Jan 1, 1970
0
[email protected] wrote...
I assume this is NOT the 4024 CMOS chip? I am in desperate need
of some 4024s in the metal can package (they are no longer made).

You're referring to the cd4024T in a 12-lead TO-5-size package?
 
T

Tim Shoppa

Jan 1, 1970
0
I assume this is NOT the 4024 CMOS chip? I am in desperate need of some 4024s
in the metal can package (they are no longer made).

These are not CMOS, they are good old MC4024 bipolar process VCO's. If
you get me your mailing address I can get you these in plastic or ceramic
DIP's. You can probably rig up an adapter to get them to your circular
pinout. (It was always easier to go the other way around and put the
TO-can legs in DIP pattern holes.)

Tim.
 
T

Tim Shoppa

Jan 1, 1970
0
Jim Thompson said:
3,649,929 Sine and Square-Wave Oscillator with AGC - MC1648

Wow, that's a good read. I did much better with that than I do
with most patents. I feel like taking some CA3046's or discrete
transistors and playing around with the ideas!

The MC1648 data sheet says it only works with LC tanks and not with
crystals, but if I built one out of transistors it would probably
oscillate with a series-resonant crystal where the wire is between
the collector of one Q and the base of the other Q? (A resistor or
RFC from the collector to Vcc too).

Tim.
 
J

Jim Thompson

Jan 1, 1970
0
Wow, that's a good read. I did much better with that than I do
with most patents. I feel like taking some CA3046's or discrete
transistors and playing around with the ideas!

The MC1648 data sheet says it only works with LC tanks and not with
crystals, but if I built one out of transistors it would probably
oscillate with a series-resonant crystal where the wire is between
the collector of one Q and the base of the other Q? (A resistor or
RFC from the collector to Vcc too).

Tim.

It should, though my favorite approach is emitter-coupled... XTAL
between emitters, resistors to ground from each emitter, tank in one
collector, direct to VCC for the other collector. Connect "tank
collector" to base of other device, base of device with tank to VCC.

Hope that's clear... I despise ASCII schematics :)

...Jim Thompson
 
J

Jim Thompson

Jan 1, 1970
0
Wow, that's a good read. I did much better with that than I do
with most patents.
[snip]

I should have commented in my other post:

I always work closely with patent attorneys, and pretty-much write the
patent myself (except for the legalese in the claims), otherwise
they'll describe and claim all the wrong things ;-)

...Jim Thompson
 
Top