Resistor Values, MC1648

matic on the data sheet?

Jim Thompson certainly will - he claims to have designed it.

Since the current drain for the circuit as a whole is listed as 41mA, and y ou know the voltages coming out, it should be possible to work out the resi stor values from scratch - it's not a large circuit. Since Jim Thompson wil l presumably tell us what they are, it would be something of a waste of tim e for anybody else to try and work out plausible values.

The Motorola circuit diagram that I found didn't show the negative rail for the chip to be connected to Vee, which should be a typo - there presumably should have been a dot on the lead connecting the free end of the resistor tied to the base of Q8 to Vee.

--
Bill Sloman, Sydney

Who me? I designed it ;-)

Tomorrow. ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

With so much Analog going EOL this week, I'd like to be able keep using one of my favorite parts... Hence the question...

Steve

Unfortunately I haven't been able to find those resistor values :-[

I designed it 51 years ago, so the values are foggy... I might be able to back it out from current consumption... I tend to be very consistent in my ways ;-)

Why do you need the internal values?

Where have you been buying the MC1648? I think Lansdale still sells it.

There's also the MC12148, alter version, that is faster. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
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| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
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I love to cook with wine.     Sometimes I even put it in the food.

Can you still get them?

There are tons of all-done VCOs on the market these days.

Anybody ever seen just how they test and package old dice at Lansdale or the other big place ("leading edge of trailing technology")that claims to have all the designs and test equipment from decades ago for all sort of chips?

How the heck do they maintain that equipment? Is there some 500,000sf warehouse full of this equipment, and filing cabinets full of prints and masks and some old guy that sort of remembers a few details?

Will these places really make me a radiation hardened 64 bit memory chip on sapphire if I pay for it, if they lack the dice? Where would they even have old dusty wafers made?

Lansdale bought up a lot of the old equipment as well as EOL die AND mask sets. I visited there (Tempe, AZ) some years ago... pretty impressive equipment, small number of employees... high prices for legacy ;-)

I probably have a die photo of the MC1648 somewhere from which I could back out the resistor values (sheet rho was 200 Ohms/square AND the schematic IS correct except for no values).

I don't know about SOS (shredded beef in gravy on toast, aka shit-on-shingle >:-} but there are still lots of small foundries running legacy processes... a lot of the world still needs +/- 30V OpAmps... these recent 3.3V designs can't do the trick. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

There still have to be some processes that are just plain out dead though. Who's keeping docs on how these are performed, after everything is adjusted to make things production ready? It seems like there's just lots of lost knowledge there, sort of like how would you anybody setup a typewritter assembly line for maximum output.

Sooner or later everything reaches EOL... even me... coming up on 76

...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

If you want small quantities from Lansdale you might be in for a shock... Last two times I talked to them, they really want you to buy a few wafers, diced, sliced and processed. I can understand why they cannot make a profit for stocking onesies.

Yes, I can buy stock VCOs. But some times rolling your own is more fun and useful.

Steve

Say you need just a few pieces and they want to sell wafers. Say you buy the wafers and just toss what you don't need.

Are you looking at chips that are like $10,000 a piece or something like that in the end?

If you want to roll your own, the MC1648 skeleton is NOT the way to go... it's 51 years old, pre-PNP's, pre-CMOS.

The way to go _is_ with a bipolar diff-pair as the core (as in the MC1648)... guaranteed to oscillate, and AGC-able via the tail current.

Just use a high speed comparator to measure peak amplitude and _slowly_ adjust tail current. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

On Wed, 14 Oct 2015 18:46:59 -0700 (PDT) snipped-for-privacy@gmail.com wrote in Message id: :

Just came across this one.

No idea if it's accurate...

That's my MC1648 plus some amplification (MC1648 nominally produces only 300mV P-P) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Doh! Of course... (Not paying attention.)

:)

-Lasse

The MC1648 features AGC which gives it pretty decent (for the era *) spectral characteristics, plus has a PECL output to loop back to a phase detector.

(*) Modern version...

(I can't show the guts... it's an actual chip design protected by NDA... but it's a diff-pair LC tank oscillator AGC'd via the tail current. AGC voltage was measured as this was used in a way to sense the environment the LC tank was immersed in :-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.