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My pcb has a vlsi with a pad through which i must draw or inject current.A cpld (XC2C32A) will control the digital signal and when '0' i want to source current and sink when '1'.
I would prefer -10uA to 10uA and as for the voltage source i have some regulators that provide me +1.8V, +3.3V, +5V and -5V respectively.Will any of these do?
I would prefer -10uA to 10uA and as for the voltage source i have some regulators that provide me +1.8V, +3.3V, +5V and -5V respectively.Will any of these do?
No, I mean how far from ground (how many volts, millivolts, kilovolts) will the node that you are sinking or sourcing current to/from move away from ground potential.
When I asked you what sort of digital signal you said 1 bit, for source or sink. Would you like to redefine it?
Are you using 1 bit for source or sink and another 10 bits (parallel) to determine current?
+/- 5V may be a constraining factor.
When I asked you what sort of digital signal you said 1 bit, for source or sink. Would you like to redefine it?
Are you using 1 bit for source or sink and another 10 bits (parallel) to determine current?
+/- 5V may be a constraining factor.
Who are "they". And why are you being asked to design something when you admit you have so few skills?
If you're thinking about a potentiometer and saying "10 bit resolution" in the same breath, then I fear you lack some basic understanding.
You need to know how much voltage swing will be required otherwise you can't know what supply voltages are going to be needed.
How can anyone design something if they have no idea of the basic parameters?
What are you doing?
It's for school,everyone has to start from somewhere.
I know that potentiometers provide constant values,i just wanted to say if there are potentiometers with equivalent precision,as a DAC with 10 bits resolution.I mean i imagine it's hard to adjust a pot from say 1.01uA to go to 1.02uA.
I know that potentiometers provide constant values,i just wanted to say if there are potentiometers with equivalent precision,as a DAC with 10 bits resolution.I mean i imagine it's hard to adjust a pot from say 1.01uA to go to 1.02uA.
If it's for school, then it belongs in homework help.
It also means that you should have a better definition of the problem than what you've given us so far.
How about you tell us *exactly* what your assignment is and we'll try to help you understand the question.
It also means that you should have a better definition of the problem than what you've given us so far.
How about you tell us *exactly* what your assignment is and we'll try to help you understand the question.
I have to design a pcb to test some structures of a vlsi.(I didn't design the vlsi,just the pcb to be placed on and check some functions of it).I have the pin description and some documents about the vlsi and i have almost finished the schematic.This is the last thing i have to do,what further information about the current source are required to proceed?
If there is something else missing i could ask my professor
If there is something else missing i could ask my professor
The main thing to ask is how he wants you to control the constant current source. From the description it sounds like you are driving it with a digital signal, however that current sink/source may be an A-D and he is expecting a 10 bit digital signal from it.
He may just want a big fancy knob, perhaps on a multi-turn pot to make it more easily adjustable.
He may just want a big fancy knob, perhaps on a multi-turn pot to make it more easily adjustable.
Well, pots can give you far more precision, but generally far less accuracy. Which is more important.
Unless his use of the term "10 bit" was an irrelevant throw-away, you've got to assume it means something.
OK, is this an assignment (or similar) or are you a grad-student who's been given a really vague "do this" from his professor?
Unless his use of the term "10 bit" was an irrelevant throw-away, you've got to assume it means something.
OK, is this an assignment (or similar) or are you a grad-student who's been given a really vague "do this" from his professor?
No,i haven't got my degree yet.Everyone has an assignment to work for the semester and this is mine,but it's up to us to decide how we want to do it,there is nothing strict.
If we can do it with a pot,it would be ok.Even if i want to implement it with a DAC later i will be able to change the design my self.
If we can do it with a pot,it would be ok.Even if i want to implement it with a DAC later i will be able to change the design my self.
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