I am planning on making a +5V supply for DAC board.A bit unsure what are the parts used /recommended after reading the few pages.Does anyone has a readily available parts list for SALAS REFLEKTOR. Perhaps which are the critical components that need high quality (1% tolerance and low ESR CAPS etc) parts. A list is much appreciated though.
Thanks Salas. Which all resistors and caps are critical in the circuit.What is the maximum current draw possible from this circuit?
R7 can be a special one like Vishay VAR. All others can be 100ppm Dale or alike.
C1 can be a good polypropylene of your preference. C2 can be Nichicon Muse, Elna Silmic II. Q1,Q2 you can tie them face to face. As shown with 2.7 Ohm R1 it should draw about 250mA and you can use it for up to 150mA load with good results. In case you want more, the CCS is set with ICCS=VbeQ5/R1. As long as you burn 100-150mA spare above max load, you can scale it correctly.
C1 can be a good polypropylene of your preference. C2 can be Nichicon Muse, Elna Silmic II. Q1,Q2 you can tie them face to face. As shown with 2.7 Ohm R1 it should draw about 250mA and you can use it for up to 150mA load with good results. In case you want more, the CCS is set with ICCS=VbeQ5/R1. As long as you burn 100-150mA spare above max load, you can scale it correctly.
P.S. Don't push the 9610 above 1A. If stronger current is needed find a more capable Mosfet with relatively low Ciss characteristic. Safe operation area and sinking needs must be studied in each particular case.
Thanks Salas.My plan is to use one of reflektors with raspberry pi with a maximum rated current draw close to 600mA. What should be the value of R1 to choose. Will I.5Ohm be close?
It depends on the Vbe your Q5 is going to show. If we assume 0.65V then you will need a 0.82R 2W resistor.
In the end you will verify the practical voltage drop across R1 which is Vbe and you will divide by R1 value to know your exact CCS current.
Much appreciated.Thank you.🙂.Do you think I will need a heatsink with that kind of power needs? Which all semiconductors need a heatsink?
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I recommend that you investigate whether adding an electrolytic across Q5 Collector/Emitter works to reject interference
Some PNP with low noise. BC327-25 for instance. Slower though, 12pF Cob vs 8.5pF. Half the fT.
Thanks Salas. What is the possible substitute for the 1.8 and 1.9V LED? What is the anticipated effect on circuit with a slower transistor Like BC327?
Why you would want to sub the LEDS? With that output Mosfet type's Vgs it will create about 2mA through the mirror legs and Vf or Vbe won't be max. Use one green one red as the guys did and if its more than 5V use two same red.
Somewhat less bandwidth and phase margin is anticipated. Its not wise changing types in working examples proposed by users when 2N4403 are very easy to find and very cheap is my 2C.
Somewhat less bandwidth and phase margin is anticipated. Its not wise changing types in working examples proposed by users when 2N4403 are very easy to find and very cheap is my 2C.
Salas eventhough it is easy for me to source them in US, I have a friend in India who is verymuch following this thread and asking these questions as there is difficulty in sourcing these components. Even LED is a tough task to find when it comes to exact specs.That is why I am asking these substitute questions.
It is also hard to find 2Sk117 there. Can 2SK118 can be used or what about 2SK170?
It is also hard to find 2Sk117 there. Can 2SK118 can be used or what about 2SK170?
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Can he find BC560? For LEDs ref he can synthesize 3.8V from yellow, red, IR, 1N4148 as a mixed team in any form testing at 2mA. 2SK118 can be used at 1-2mA IDSS without the associated resistor for the 2SK117. Its bit noisier in lower source impedance though. Not too relevant here of course.
He is trying to get 2N4403 online. Is there any modification needed if he chose to use BC560.
So if I use 2SK118 I can omit the 82 ohm resistor from George's circuit?
I am unsure about the combination of LED since the problem for my friend is to get LED with exact specs and not obtaining LED. As an example he got few LED which local vendors claim as 1.9 and 1.8 but no way to check their claims. Thy is why I wad preceding to go with a part number with the expectation of getting an exact match.I saw some circuits in grid forum with a diode? used in place of LED. Is that an option?
So if I use 2SK118 I can omit the 82 ohm resistor from George's circuit?
I am unsure about the combination of LED since the problem for my friend is to get LED with exact specs and not obtaining LED. As an example he got few LED which local vendors claim as 1.9 and 1.8 but no way to check their claims. Thy is why I wad preceding to go with a part number with the expectation of getting an exact match.I saw some circuits in grid forum with a diode? used in place of LED. Is that an option?
There is Reflektor and there is an example of it as George put it together. I can't know what ifs in certainty. You got to try it with what there is available and seems close enough. If you will have problems bring your experimental data first. For 2mA idss low noise FETs you won't need the moderation resistor. Those circuits are not for kits or products, only for personal use BTW.
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