May 23, 2012 #1 S stud.taneja Newbie level 6 Joined Sep 15, 2011 Messages 12 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,348 how do we generate a ramp voltage for comparator offset voltage calculation on a SOC for analog built-in-self test application?
how do we generate a ramp voltage for comparator offset voltage calculation on a SOC for analog built-in-self test application?
May 23, 2012 #2 erikl Super Moderator Staff member Joined Sep 9, 2008 Messages 8,108 Helped 2,695 Reputation 5,370 Reaction score 2,305 Trophy points 1,393 Location Germany Activity points 44,123 Constant current into and out of a capacitor. If your SOC includes a DAC anyway, you could use it together with a (slow) clock and a binary counter, s. this posting! Last edited: May 23, 2012
Constant current into and out of a capacitor. If your SOC includes a DAC anyway, you could use it together with a (slow) clock and a binary counter, s. this posting!
May 23, 2012 #3 S stud.taneja Newbie level 6 Joined Sep 15, 2011 Messages 12 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,348 but that would create discrete voltage levels is there any way to generate a perfect ramp without using complicated circuits
but that would create discrete voltage levels is there any way to generate a perfect ramp without using complicated circuits
May 23, 2012 #4 erikl Super Moderator Staff member Joined Sep 9, 2008 Messages 8,108 Helped 2,695 Reputation 5,370 Reaction score 2,305 Trophy points 1,393 Location Germany Activity points 44,123 stud.taneja said: that would create discrete voltage levels Click to expand... Does it matter if you have a fine resolution? stud.taneja said: is there any way to generate a perfect ramp without using complicated circuits Click to expand... Sure; told you above! Another way: A SOC surely has a clock. Divide it down to an appropriate frequency and integrate it to a triangle ramp.
stud.taneja said: that would create discrete voltage levels Click to expand... Does it matter if you have a fine resolution? stud.taneja said: is there any way to generate a perfect ramp without using complicated circuits Click to expand... Sure; told you above! Another way: A SOC surely has a clock. Divide it down to an appropriate frequency and integrate it to a triangle ramp.
May 23, 2012 #5 S stud.taneja Newbie level 6 Joined Sep 15, 2011 Messages 12 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,348 yes it does matter a lot as i have to measure the comparator offset voltages which are in mV integration thing is OK but it will require a cap which will bring a large area
yes it does matter a lot as i have to measure the comparator offset voltages which are in mV integration thing is OK but it will require a cap which will bring a large area
May 23, 2012 #6 erikl Super Moderator Staff member Joined Sep 9, 2008 Messages 8,108 Helped 2,695 Reputation 5,370 Reaction score 2,305 Trophy points 1,393 Location Germany Activity points 44,123 stud.taneja said: yes it does matter a lot as i have to measure the comparator offset voltages which are in mV Click to expand... There are DACs with sub-mV resolution. Seems you don't have one, poor guy! stud.taneja said: integration thing is OK but it will require a cap which will bring a large area Click to expand... Depends on your comparator speed: 10nA/10pF = 1mV/µs could be a compromise. Otherwise use my 3rd suggestion: slow clock integration.
stud.taneja said: yes it does matter a lot as i have to measure the comparator offset voltages which are in mV Click to expand... There are DACs with sub-mV resolution. Seems you don't have one, poor guy! stud.taneja said: integration thing is OK but it will require a cap which will bring a large area Click to expand... Depends on your comparator speed: 10nA/10pF = 1mV/µs could be a compromise. Otherwise use my 3rd suggestion: slow clock integration.
May 24, 2012 #7 S stud.taneja Newbie level 6 Joined Sep 15, 2011 Messages 12 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,348 we do have a dac with sub-mV threshhold but i need one for high frequency interfacing (250 MHz - 500 MHz) . Are such DACs available ---------- Post added at 15:48 ---------- Previous post was at 14:56 ---------- also tell the possibility of generating a sine wave using PWM
we do have a dac with sub-mV threshhold but i need one for high frequency interfacing (250 MHz - 500 MHz) . Are such DACs available ---------- Post added at 15:48 ---------- Previous post was at 14:56 ---------- also tell the possibility of generating a sine wave using PWM