Cool, you still know what LDO stands for! Many engineers seem to think it's synonymous with series regulator.
I take that as a compliment.
Patrick
DIY members complimenting each other - how refreshing on a Sunday morning!
Not all is lost it seems 😎
Jan
Not all is lost it seems 😎
Jan
Put the lack of understanding together with the prevailing audiophile dogma and you get people who replace the supposedly crappy 10uF X7R (not to mention X5R) LT304x output cap with a huge audiophile-approved through-hole film cap and then blame LT304x for the poor resultMark, the capacitor is used for DC decoupling- not AC signal coupling. Most here would never use a class II dielectric for the latter function. Film and electrolytic caps are severely limited at HF because of ESL/ESR - the very things you say X7R are bad at.

What I'd really want is a lt3042 for grown up men. Say TO-220-5
A while ago, Jan and I did discuss whether a DIY version can be made.
The idea is to allow more flexibilities, whether higher voltage (100's of volts) or higher current (2~5A or so).
It turns out to be more difficult than I thought, but then I am not fit with opamps anyhow.
So maybe the guru's here have better ideas.
The LT304x essentially consists of 2 parts :
1) a voltage reference consisting of a stable current source, a resistor for converting current to voltage, and a cap to suppress the noise;
2) an opamp in follower mode to drive the output load.
The input voltage of the LT304x is limited to 20V.
In theory one can float its "Gnd" to allow much higher voltage.
But the voltage at the opamp +Vin has to be restrained at start up, or the opamp will die.
Increase in current can be done with external PNP or NPN, as in 3042 datasheet P.27.
But can we not just do it with a high-power opamp, or an opamp plus a FET, e.g. ?
The current source is not so difficult.
A long tail JFET plus a source resistor will get us a 10~100µA CCS which is probably stable and low noise enough.
But getting a unity-gain stable, high current opamp to remain so with a high capacitive load is not always simple.
The other features we don't always need.
At least I don't, other than current limit, at times.
Patrick
I must be getting too old for this. I totally forgot that I had changed the AVCC setup in my ES9038Q2M. LT3042 is the regulator but it does not feed AVCC. The following op amp buffer feeds both AVCC and I/V reference. No wonder it sounds so good in subjective sighted listening tests 🙂 But in my AK4490 design LT3042 feeds the Vref directly. That sounds even better
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@bohrok2610I belive anybody claiming hearing differences between non pathological DAC implementation (and all Toppings products are definitely not) is not a discussion serious partner, and qualifies as a delusional audiphool.,,,
Since we all know that you are no audiophool, there is a good chance your implementation of ES9038Q2M or both is somewhat pathological.
For higher currents there already is LT8627SP. The package however is not exactly TO-220-5 🙂What I'd really want is a lt3042 for grown up men. Say TO-220-5
even when PowerGood is missing.
Not only that. My ears are normally so filled with wax that I probably only heard the wax resonating and giving a sensation of a much wider and higher soundstage 🙂@bohrok2610
Since we all know that you are no audiophool, there is a good chance your implementation of ES9038Q2M or both is somewhat pathological.
So you need less than 4uVrms noise at 16A?LT8627 is a switcher with 5x RMS noise.
Not ?
Patrick
My ears are normally so filled with wax ...
Precious earwax, worth it's weight in gold. 😀
Patrick, you basically describe my T-reg regulator 😎A while ago, Jan and I did discuss whether a DIY version can be made.
The idea is to allow more flexibilities, whether higher voltage (100's of volts) or higher current (2~5A or so).
It turns out to be more difficult than I thought, but then I am not fit with opamps anyhow.
So maybe the guru's here have better ideas.
The LT304x essentially consists of 2 parts :
1) a voltage reference consisting of a stable current source, a resistor for converting current to voltage, and a cap to suppress the noise;
2) an opamp in follower mode to drive the output load.
The input voltage of the LT304x is limited to 20V.
In theory one can float its "Gnd" to allow much higher voltage.
But the voltage at the opamp +Vin has to be restrained at start up, or the opamp will die.
Increase in current can be done with external PNP or NPN, as in 3042 datasheet P.27.
But can we not just do it with a high-power opamp, or an opamp plus a FET, e.g. ?
The current source is not so difficult.
A long tail JFET plus a source resistor will get us a 10~100µA CCS which is probably stable and low noise enough.
But getting a unity-gain stable, high current opamp to remain so with a high capacitive load is not always simple.
The other features we don't always need.
At least I don't, other than current limit, at times.
Patrick
Using a current source and R to set the (filtered) ref, a floating opamp error amp and a pass element.
It works from 5V or so to 500V by changing just 1 resistor ...
Jan
But not 2~5A ?
Or you already tested all combinations ? 🙂
BTW, the current source you use is seemingly not particularly low noise.
Patrick
Or you already tested all combinations ? 🙂
BTW, the current source you use is seemingly not particularly low noise.
Patrick
400mA @ 500V with the 12N60xxx.But not 2~5A ?
Or you already tested all combinations ? 🙂
BTW, the current source you use is seemingly not particularly low noise.
Patrick
A hefty FET gives you 5A at up to, ohh, 100V?
Choose your pass device by SOA, set the current limit accordingly, and the sky is the limit!
And the ref noise can be made almost arbitrarily low.
Jan
For the record, it was Hilbiber's article in the 1964 ISSCC Digest of Technical Papers rather than Electronics Letters. Apparently this was the very first article about bandgap references. In the early 1970's, variants that needed much less voltage and produced much more noise were developped, and those are used everywhere now.You can stack instead of amplify PTAT voltages, that's the way the bandgap from the 1960's Electronics Letters article works. That's much less noisy.
Hilbiber's article in the 1964 ISSCC Digest of Technical Papers
Attachments
Yes, that's the one.
Where did you find it? You normally have to pay a fortune to access anything via the IEEE site.
Where did you find it? You normally have to pay a fortune to access anything via the IEEE site.
https://class.ece.iastate.edu/djchen/ee501/2013/BandGapRefOriginalPaperByD.F.HilbiberISSCC1964.pdfWhere did you find it?
It's Iowa State, but may not be a "valid" website (it may be old files not intentionally exposed).
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