On 26 Jun 2019 10:52:37 -0700, Winfield Hill <winfieldhill@yahoo.com> wrote:>John Larkin wrote... >> >> How about this? >>https://www.dropbox.com/s/1gud5ftlsmnsqtx/Wide_Range_TIA.jpg?raw=1 > > That could work, sort of. The beauty of the > Eckel circuit is the substantial range of its > overlapping simultaneous outputs, as you go > through range changes. > > You won't be trying to digitize an opamp all > the way to its saturation, and wait for the > next stage to begin working. > > If you have a very noisy signal, having two > amplifier signal versions, at different gains, > lets you process data from two channals and > get a clean result. > > Note, it has a similar parts count: one opamp > per range, and JFET instead of a diode. It'd > be a good addition to your bag of tricks. > > Also, Eckel's circuit can work through zero, > with bipolar input currents.Mine can work bipolar, with more diodes. But a photodiode deosn't need bipolar. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
9-decade transimpedance amplifier
Started by ●June 26, 2019
Reply by ●June 26, 20192019-06-26
Reply by ●June 26, 20192019-06-26
On Wednesday, June 26, 2019 at 12:48:43 PM UTC-4, Winfield Hill wrote:> Here's a TIA circuit published in 2012, in RSI, > by Yale physicist, Stephen Eckel. “A high dynamic > range, linear response transimpedance amplifier.” > > It's easy to implement, and super useful. The TIA > has multiple ranges, each with its own output, but > multiple ranges are active at once; there's no loss > of data as would happen switching range resistors. > > Stephen and his co-authors found a simple, clever > trick to prevent input TIA opamp saturation, using > JFETs to successively short series-placed higher- > value range resistors for strong input currents. > > They suggest a three-stage implementation, with a > 300:1 ratio for each, but you can use many stages > (each one takes few extra parts), to obtain high > accuracy with a say 12-bit ADC. Also, a high > input-opamp Vos needn't degrade the dynamic range. > > DropBox has a draft of our x-Chapters write-up: > https://www.dropbox.com/s/fs4edz7dqgwswoj/4x.3.7_Eckel_TIA.pdf?dl=0 > > I think you can download Stephen's RSI article here: > https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUKEwjk6KvVwYfjAhVlRN8KHaMfD48QFjAHegQICRAC&url=http%3A%2F%2Fwww.bmo.physik.uni-muenchen.de%2F~riedle%2FElektronik_I%2FKW103%2F2012_Eckel%2CSushkov_9-decade_RSI.pdf&usg=AOvVaw3g9i6-pWAwuuZlZLvlFArd > > > -- > Thanks, > - WinFun Thanks. George H.
Reply by ●June 26, 20192019-06-26
On Wednesday, June 26, 2019 at 1:24:07 PM UTC-4, John Larkin wrote:> On 26 Jun 2019 09:48:33 -0700, Winfield Hill <winfieldhill@yahoo.com> > wrote: > > > Here's a TIA circuit published in 2012, in RSI, > > by Yale physicist, Stephen Eckel. “A high dynamic > > range, linear response transimpedance amplifier.” > > > > It's easy to implement, and super useful. The TIA > > has multiple ranges, each with its own output, but > > multiple ranges are active at once; there's no loss > > of data as would happen switching range resistors. > > > > Stephen and his co-authors found a simple, clever > > trick to prevent input TIA opamp saturation, using > > JFETs to successively short series-placed higher- > > value range resistors for strong input currents. > > > > They suggest a three-stage implementation, with a > > 300:1 ratio for each, but you can use many stages > > (each one takes few extra parts), to obtain high > > accuracy with a say 12-bit ADC. Also, a high > > input-opamp Vos needn't degrade the dynamic range. > > > > DropBox has a draft of our x-Chapters write-up: > >https://www.dropbox.com/s/fs4edz7dqgwswoj/4x.3.7_Eckel_TIA.pdf?dl=0 > > > > I think you can download Stephen's RSI article here: > >https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUKEwjk6KvVwYfjAhVlRN8KHaMfD48QFjAHegQICRAC&url=http%3A%2F%2Fwww.bmo.physik.uni-muenchen.de%2F~riedle%2FElektronik_I%2FKW103%2F2012_Eckel%2CSushkov_9-decade_RSI.pdf&usg=AOvVaw3g9i6-pWAwuuZlZLvlFArd > > > How about this? > > https://www.dropbox.com/s/1gud5ftlsmnsqtx/Wide_Range_TIA.jpg?raw=1Huh, So first I assume the higher gains, (bigger Rs) are on top.. behind the diodes. Then a question; how does the current 'know' which path to take? Oh, If I put the high range on the bottom, then when it can't handle any more next one up takes over... Is that right? That's cute too! George H.> > > > -- > > John Larkin Highland Technology, Inc > picosecond timing precision measurement > > jlarkin att highlandtechnology dott com > http://www.highlandtechnology.com
Reply by ●June 26, 20192019-06-26
Winfield Hill <winfieldhill@yahoo.com> wrote:> Here's a TIA circuit published in 2012, in RSI, > by Yale physicist, Stephen Eckel. �A high dynamic > range, linear response transimpedance amplifier.� > > It's easy to implement, and super useful. The TIA > has multiple ranges, each with its own output, but > multiple ranges are active at once; there's no loss > of data as would happen switching range resistors. > > Stephen and his co-authors found a simple, clever > trick to prevent input TIA opamp saturation, using > JFETs to successively short series-placed higher- > value range resistors for strong input currents. > > They suggest a three-stage implementation, with a > 300:1 ratio for each, but you can use many stages > (each one takes few extra parts), to obtain high > accuracy with a say 12-bit ADC. Also, a high > input-opamp Vos needn't degrade the dynamic range. > > DropBox has a draft of our x-Chapters write-up: > https://www.dropbox.com/s/fs4edz7dqgwswoj/4x.3.7_Eckel_TIA.pdf?dl=0 > > I think you can download Stephen's RSI article here: > https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUK > Ewjk6KvVwYfjAhVlRN8KHaMfD48QFjAHegQICRAC&url=http%3A%2F%2Fwww.bmo.physik. > uni-muenchen.de%2F~riedle%2FElektronik_I%2FKW103%2F2012_Eckel%2CSushkov_9 > -decade_RSI.pdf&usg=AOvVaw3g9i6-pWAwuuZlZLvlFArdEasier download link: http://www.bmo.physik.uni-muenchen.de/~riedle/Elektronik_I/KW103/2012 _Eckel,Sushkov_9-decade_RSI.pdf
Reply by ●June 26, 20192019-06-26
Steve Wilson wrote...> > Winfield Hill wrote: > >> I think you can download Stephen's RSI article here: ... > > Easier download link: > >http://www.bmo.physik.uni-muenchen.de/~riedle/Elektronik_I/KW103/2012 >_Eckel,Sushkov_9-decade_RSI.pdfIt appears some people were paying attention, and trying to get the word out, past the paywall. -- Thanks, - Win
Reply by ●June 26, 20192019-06-26
On Wed, 26 Jun 2019 12:19:35 -0700 (PDT), George Herold <gherold@teachspin.com> wrote:>On Wednesday, June 26, 2019 at 1:24:07 PM UTC-4, John Larkin wrote: >> On 26 Jun 2019 09:48:33 -0700, Winfield Hill <winfieldhill@yahoo.com> >> wrote: >> >> > Here's a TIA circuit published in 2012, in RSI, >> > by Yale physicist, Stephen Eckel. �A high dynamic >> > range, linear response transimpedance amplifier.� >> > >> > It's easy to implement, and super useful. The TIA >> > has multiple ranges, each with its own output, but >> > multiple ranges are active at once; there's no loss >> > of data as would happen switching range resistors. >> > >> > Stephen and his co-authors found a simple, clever >> > trick to prevent input TIA opamp saturation, using >> > JFETs to successively short series-placed higher- >> > value range resistors for strong input currents. >> > >> > They suggest a three-stage implementation, with a >> > 300:1 ratio for each, but you can use many stages >> > (each one takes few extra parts), to obtain high >> > accuracy with a say 12-bit ADC. Also, a high >> > input-opamp Vos needn't degrade the dynamic range. >> > >> > DropBox has a draft of our x-Chapters write-up: >> >https://www.dropbox.com/s/fs4edz7dqgwswoj/4x.3.7_Eckel_TIA.pdf?dl=0 >> > >> > I think you can download Stephen's RSI article here: >> >https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUKEwjk6KvVwYfjAhVlRN8KHaMfD48QFjAHegQICRAC&url=http%3A%2F%2Fwww.bmo.physik.uni-muenchen.de%2F~riedle%2FElektronik_I%2FKW103%2F2012_Eckel%2CSushkov_9-decade_RSI.pdf&usg=AOvVaw3g9i6-pWAwuuZlZLvlFArd >> >> >> How about this? >> >> https://www.dropbox.com/s/1gud5ftlsmnsqtx/Wide_Range_TIA.jpg?raw=1 >Huh, So first I assume the higher gains, (bigger Rs) are on top.. >behind the diodes. Then a question; how does the current 'know' which path >to take? > >Oh, If I put the high range on the bottom, then when it can't handle any >more next one up takes over... Is that right? That's cute too! > >George H.Right, higher gain, big Rf, is on the bottom. When that stage rails, the excess input current moves up to the next stage. The diode drop produces a low-order error that is easily fudged away. It only works right with a current-source input. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●June 26, 20192019-06-26
On 26/06/2019 5:48 pm, Winfield Hill wrote:> Here's a TIA circuit published in 2012, in RSI, > by Yale physicist, Stephen Eckel. “A high dynamic > range, linear response transimpedance amplifier.” > > It's easy to implement, and super useful. The TIA > has multiple ranges, each with its own output, but > multiple ranges are active at once; there's no loss > of data as would happen switching range resistors. > > Stephen and his co-authors found a simple, clever > trick to prevent input TIA opamp saturation, using > JFETs to successively short series-placed higher- > value range resistors for strong input currents. > > They suggest a three-stage implementation, with a > 300:1 ratio for each, but you can use many stages > (each one takes few extra parts), to obtain high > accuracy with a say 12-bit ADC. Also, a high > input-opamp Vos needn't degrade the dynamic range. > > DropBox has a draft of our x-Chapters write-up: > https://www.dropbox.com/s/fs4edz7dqgwswoj/4x.3.7_Eckel_TIA.pdf?dl=0 > > I think you can download Stephen's RSI article here: > https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUKEwjk6KvVwYfjAhVlRN8KHaMfD48QFjAHegQICRAC&url=http%3A%2F%2Fwww.bmo.physik.uni-muenchen.de%2F~riedle%2FElektronik_I%2FKW103%2F2012_Eckel%2CSushkov_9-decade_RSI.pdf&usg=AOvVaw3g9i6-pWAwuuZlZLvlFArd > >Marvellous - thank you! Jfets are nice because when fully depleted off there is no parasitic s-d diode that curses gumdrop mosfets. But gumdrop mosfets are much cheaper than jfets these days. I wonder if one could use series connected source-source 2N7002 and s-s BSS84 to replace those jfets? Eight mosfets could work out cheaper than four jfets? While gate leakage should be a non-issue I don't know how s-d channel leakage compares? piglet
Reply by ●June 26, 20192019-06-26
On Wednesday, June 26, 2019 at 4:06:48 PM UTC-4, John Larkin wrote:> On Wed, 26 Jun 2019 12:19:35 -0700 (PDT), George Herold > <gherold@teachspin.com> wrote: > > >On Wednesday, June 26, 2019 at 1:24:07 PM UTC-4, John Larkin wrote: > >> On 26 Jun 2019 09:48:33 -0700, Winfield Hill <winfieldhill@yahoo.com> > >> wrote: > >> > >> > Here's a TIA circuit published in 2012, in RSI, > >> > by Yale physicist, Stephen Eckel. “A high dynamic > >> > range, linear response transimpedance amplifier.” > >> > > >> > It's easy to implement, and super useful. The TIA > >> > has multiple ranges, each with its own output, but > >> > multiple ranges are active at once; there's no loss > >> > of data as would happen switching range resistors. > >> > > >> > Stephen and his co-authors found a simple, clever > >> > trick to prevent input TIA opamp saturation, using > >> > JFETs to successively short series-placed higher- > >> > value range resistors for strong input currents. > >> > > >> > They suggest a three-stage implementation, with a > >> > 300:1 ratio for each, but you can use many stages > >> > (each one takes few extra parts), to obtain high > >> > accuracy with a say 12-bit ADC. Also, a high > >> > input-opamp Vos needn't degrade the dynamic range. > >> > > >> > DropBox has a draft of our x-Chapters write-up: > >> >https://www.dropbox.com/s/fs4edz7dqgwswoj/4x.3.7_Eckel_TIA.pdf?dl=0 > >> > > >> > I think you can download Stephen's RSI article here: > >> >https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUKEwjk6KvVwYfjAhVlRN8KHaMfD48QFjAHegQICRAC&url=http%3A%2F%2Fwww.bmo.physik.uni-muenchen.de%2F~riedle%2FElektronik_I%2FKW103%2F2012_Eckel%2CSushkov_9-decade_RSI.pdf&usg=AOvVaw3g9i6-pWAwuuZlZLvlFArd > >> > >> > >> How about this? > >> > >> https://www.dropbox.com/s/1gud5ftlsmnsqtx/Wide_Range_TIA.jpg?raw=1 > >Huh, So first I assume the higher gains, (bigger Rs) are on top.. > >behind the diodes. Then a question; how does the current 'know' which path > >to take? > > > >Oh, If I put the high range on the bottom, then when it can't handle any > >more next one up takes over... Is that right? That's cute too! > > > >George H. > > Right, higher gain, big Rf, is on the bottom. When that stage rails, > the excess input current moves up to the next stage. The diode drop > produces a low-order error that is easily fudged away. > > It only works right with a current-source input.Right PD biased up to at least -10V, or something. We sell a PD with a 10 position switch, 1,3.3,10... It's OK, when I tried to make it faster I found the switch added ~5 pF of C. Otherwise I'm not sure what's wrong with a gain switch. A lower capacitance switch would be nice. Square posts with jumpers would be less than 5pF, but more of a pain to change. George H.> > > -- > > John Larkin Highland Technology, Inc > picosecond timing precision measurement > > jlarkin att highlandtechnology dott com > http://www.highlandtechnology.com
Reply by ●June 26, 20192019-06-26
On Wednesday, June 26, 2019 at 5:22:34 PM UTC-4, piglet wrote:> On 26/06/2019 5:48 pm, Winfield Hill wrote: > > Here's a TIA circuit published in 2012, in RSI, > > by Yale physicist, Stephen Eckel. “A high dynamic > > range, linear response transimpedance amplifier.” > > > > It's easy to implement, and super useful. The TIA > > has multiple ranges, each with its own output, but > > multiple ranges are active at once; there's no loss > > of data as would happen switching range resistors. > > > > Stephen and his co-authors found a simple, clever > > trick to prevent input TIA opamp saturation, using > > JFETs to successively short series-placed higher- > > value range resistors for strong input currents. > > > > They suggest a three-stage implementation, with a > > 300:1 ratio for each, but you can use many stages > > (each one takes few extra parts), to obtain high > > accuracy with a say 12-bit ADC. Also, a high > > input-opamp Vos needn't degrade the dynamic range. > > > > DropBox has a draft of our x-Chapters write-up: > > https://www.dropbox.com/s/fs4edz7dqgwswoj/4x.3.7_Eckel_TIA.pdf?dl=0 > > > > I think you can download Stephen's RSI article here: > > https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUKEwjk6KvVwYfjAhVlRN8KHaMfD48QFjAHegQICRAC&url=http%3A%2F%2Fwww.bmo.physik.uni-muenchen.de%2F~riedle%2FElektronik_I%2FKW103%2F2012_Eckel%2CSushkov_9-decade_RSI.pdf&usg=AOvVaw3g9i6-pWAwuuZlZLvlFArd > > > > > > > Marvellous - thank you! > > Jfets are nice because when fully depleted off there is no parasitic s-d > diode that curses gumdrop mosfets. But gumdrop mosfets are much cheaper > than jfets these days. I wonder if one could use series connected > source-source 2N7002 and s-s BSS84 to replace those jfets? Eight mosfets > could work out cheaper than four jfets? While gate leakage should be a > non-issue I don't know how s-d channel leakage compares? > > pigletI was going to ask what about source-source fets, and found this, https://electronics.stackexchange.com/questions/79028/understanding-two-mosfet-with-sources-connected Is that right... just looking at pics not reading comments/ words. George H.
Reply by ●June 26, 20192019-06-26
On Wed, 26 Jun 2019 17:43:27 -0700 (PDT), George Herold <gherold@teachspin.com> wrote:>On Wednesday, June 26, 2019 at 4:06:48 PM UTC-4, John Larkin wrote: >> On Wed, 26 Jun 2019 12:19:35 -0700 (PDT), George Herold >> <gherold@teachspin.com> wrote: >> >> >On Wednesday, June 26, 2019 at 1:24:07 PM UTC-4, John Larkin wrote: >> >> On 26 Jun 2019 09:48:33 -0700, Winfield Hill <winfieldhill@yahoo.com> >> >> wrote: >> >> >> >> > Here's a TIA circuit published in 2012, in RSI, >> >> > by Yale physicist, Stephen Eckel. �A high dynamic >> >> > range, linear response transimpedance amplifier.� >> >> > >> >> > It's easy to implement, and super useful. The TIA >> >> > has multiple ranges, each with its own output, but >> >> > multiple ranges are active at once; there's no loss >> >> > of data as would happen switching range resistors. >> >> > >> >> > Stephen and his co-authors found a simple, clever >> >> > trick to prevent input TIA opamp saturation, using >> >> > JFETs to successively short series-placed higher- >> >> > value range resistors for strong input currents. >> >> > >> >> > They suggest a three-stage implementation, with a >> >> > 300:1 ratio for each, but you can use many stages >> >> > (each one takes few extra parts), to obtain high >> >> > accuracy with a say 12-bit ADC. Also, a high >> >> > input-opamp Vos needn't degrade the dynamic range. >> >> > >> >> > DropBox has a draft of our x-Chapters write-up: >> >> >https://www.dropbox.com/s/fs4edz7dqgwswoj/4x.3.7_Eckel_TIA.pdf?dl=0 >> >> > >> >> > I think you can download Stephen's RSI article here: >> >> >https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUKEwjk6KvVwYfjAhVlRN8KHaMfD48QFjAHegQICRAC&url=http%3A%2F%2Fwww.bmo.physik.uni-muenchen.de%2F~riedle%2FElektronik_I%2FKW103%2F2012_Eckel%2CSushkov_9-decade_RSI.pdf&usg=AOvVaw3g9i6-pWAwuuZlZLvlFArd >> >> >> >> >> >> How about this? >> >> >> >> https://www.dropbox.com/s/1gud5ftlsmnsqtx/Wide_Range_TIA.jpg?raw=1 >> >Huh, So first I assume the higher gains, (bigger Rs) are on top.. >> >behind the diodes. Then a question; how does the current 'know' which path >> >to take? >> > >> >Oh, If I put the high range on the bottom, then when it can't handle any >> >more next one up takes over... Is that right? That's cute too! >> > >> >George H. >> >> Right, higher gain, big Rf, is on the bottom. When that stage rails, >> the excess input current moves up to the next stage. The diode drop >> produces a low-order error that is easily fudged away. >> >> It only works right with a current-source input. >Right PD biased up to at least -10V, or something. >We sell a PD with a 10 position switch, 1,3.3,10... >It's OK, when I tried to make it faster I found the switch >added ~5 pF of C. Otherwise I'm not sure what's wrong >with a gain switch. A lower capacitance switch would be nice. >Square posts with jumpers would be less than 5pF, but more of >a pain to change. > >George H. >I did one photodiode amp using Phil's bootstrap cascode architecture, except that I used two cascode NPNs, each going to its own opamp. By seesawing the base voltages, I could select one or the other. That got me two 10:1 gain ranges. I got another 10:1 downstream. Great circuit, bad customer. -- John Larkin Highland Technology, Inc lunatic fringe electronics
