Mastodawn

Aeaeaeargh.
Some friends have challenged me to design a working ham transceiver I can make an actual QSO with, with a damn one euro (1€) component BOM, from LCSC.
Thankfully excluding shipping, so don't have to build something like 25 or 50pcs to hit the price point. :D
But it's going to be a real challenge, as I don't actually know CW.
And I want a synthetized rig for some band VHF and up. Quite possibly 2m.
As 23cm seems to require a 1,5€ or 2€ BOM to pull off.

@ftg Can you get a 5V regulator, some sort of reference crystal, a 74HC4024, some 1N4148s, 74HC4060 and 74HC4046 for that price? I reckon even that minimal synthesizer, which will still need multiplier chain or mixer to hit 2m, will be past a single €

Philip Bragg Dec 25

@ftg You may be able to do a 1MHz VFO mix synth for less

@synx508
Cheapest 74HC4024 is €0.3458
Cheapest 74HC4046 is €0.3908 (two in stock) or €0.6195. But there's tons of other 4046's as well.
Cheapest 74HC4060 is €0.1093.

So total for those would be 0.8459, before any passives, voltage regulators or even the VCO itself.

Btw a Toshiba 74VHC4040 is specified to 210MHz and costs €0.1879.

Philip Bragg Dec 25

@ftg Maybe you can use a XOR as the PD if you've got a failsafe VCO config

@synx508
Yeah a XOR is the current plan. as a single gate one is cents.
But I'm so tempted to add one 7474 and some BJT's and make it a proper phase frequency detector with charge pump output.
The very strict budget does help with scope creep. 😜

Philip Bragg Dec 25

@ftg I always forget those single gate ICs still exist

Rue Mohr Dec 25

@synx508 @ftg there is an '08 in there I think....

Henning Paul DC4HP Dec 25

@synx508 @ftg What do you mean by "still"? I learnt about their existence only 15 years ago.

Philip Bragg Dec 25

@hennichodernich @ftg There are so many ICs from that era that have since vanished, while older ICs have survived. The last time I tried to source some "tinylogic" devices I found that the range was smaller. I'm not sure if that was a temporary thing, though…

@synx508 @hennichodernich
Yeah that's the problem with the newer logic families. They just go away or are single source.
While 74HC just continues to be available in SOIC.
But the small, single or double gate parts are also good for fast designs that use them for RF, as grounding, bypassing and general layout is much easier to do well.
After other projects are done, I want to see how sharp edges I can get from a single gate NAND or inverter in DFN.

Philip Bragg Dec 25

@ftg @hennichodernich This has reminded me that the venerable 4046 was finally designed properly for typical applications and then discontinued https://www.nexperia.com/product/74HCT9046AD

74HCT9046AD (PLL with band gap controlled VCO)

74HCT9046AD - The 74HCT9046A. This device features reduced input threshold levels to allow interfacing to TTL logic levels. Inputs also include clamp diodes, this enables the use of current limiting resistors to interface inputs to voltages in excess of VCC.

Nexperia

Philip Bragg Dec 25

@ftg @hennichodernich (and the 7046 with the actually usable lock detector circuit, but that seems to be available still)

@synx508 @hennichodernich
Yeah the demise of 9046 was a damn shame.
I do still have some 7046's in my stocks, waiting for a project.

Henning Paul DC4HP Dec 25

@ftg @synx508 I consider onsemi's NC7SZ family as second source for 74LVC1G and both are easily available.

@hennichodernich @ftg @synx508 We use these things by the dozen at work for line drivers, re-drivers, signal gating, and voltage translation. Anything doing functional safety uses a pile of them to help manage fault exclusion.