Hi, all--I'm looking for a curve tracer. Ideally it would be USB-powered, and come with software that would make plots and generate data files. Nothing too fancy, just I_C and I_B vs V_CE and V_BE, and the equivalent for FETs. A plus would be automatic computation of beta, V_GSth, Early voltage, and even some of the DC SPICE parameters like emitter and base resistance. It would be especially nice if it could measure gate current with a resolution of a picoamp or less. Any suggestions? Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Curve tracers
Started by ●February 11, 2013
Reply by ●February 11, 20132013-02-11
On Mon, 11 Feb 2013 13:42:01 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>Hi, all--I'm looking for a curve tracer. Ideally it would be >USB-powered, and come with software that would make plots and generate >data files. Nothing too fancy, just I_C and I_B vs V_CE and V_BE, and >the equivalent for FETs. A plus would be automatic computation of beta, >V_GSth, Early voltage, and even some of the DC SPICE parameters like >emitter and base resistance.You could probably simply import the data points as tables into PSpice and PSpice would do the computations... and I'd guess LTspice could do the same, though it's not as robust with macros as PSpice. USB powered? If 1 Amp maximum would work. I'd be more inclined to use external power and the USB only for control and data.> >It would be especially nice if it could measure gate current with a >resolution of a picoamp or less.Only with lots of time to wait >:-} (I'd be interested as well. I've always coveted having my own curve tracer ;-)> >Any suggestions? > >Cheers > >Phil Hobbs...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●February 11, 20132013-02-11
On 02/11/2013 02:08 PM, Jim Thompson wrote:> On Mon, 11 Feb 2013 13:42:01 -0500, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> Hi, all--I'm looking for a curve tracer. Ideally it would be >> USB-powered, and come with software that would make plots and generate >> data files. Nothing too fancy, just I_C and I_B vs V_CE and V_BE, and >> the equivalent for FETs. A plus would be automatic computation of beta, >> V_GSth, Early voltage, and even some of the DC SPICE parameters like >> emitter and base resistance. > > You could probably simply import the data points as tables into PSpice > and PSpice would do the computations... and I'd guess LTspice could do > the same, though it's not as robust with macros as PSpice. > > USB powered? If 1 Amp maximum would work. I'd be more inclined to > use external power and the USB only for control and data.Curve tracers can go reasonably fast, so a big cap could provide the oomph for a brief excursion to higher power. I'm reasonably agnostic about having a wall wart too.> >> >> It would be especially nice if it could measure gate current with a >> resolution of a picoamp or less. > > Only with lots of time to wait>:-}Could be reasonably fast if they integrate the gate current. A minute for a set of 5 or 10 curves would be OK at low levels.> > (I'd be interested as well. I've always coveted having my own curve > tracer ;-) >Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●February 11, 20132013-02-11
Phil Hobbs wrote:> Hi, all--I'm looking for a curve tracer. Ideally it would be > USB-powered, and come with software that would make plots and generate > data files. Nothing too fancy, just I_C and I_B vs V_CE and V_BE, and > the equivalent for FETs. A plus would be automatic computation of beta, > V_GSth, Early voltage, and even some of the DC SPICE parameters like > emitter and base resistance. > > It would be especially nice if it could measure gate current with a > resolution of a picoamp or less. > > Any suggestions? >Quite a niche market, that probably gets expensive: http://c418683.r83.cf2.rackcdn.com/uploaded/BL_765670_e_ver2.pdf -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●February 11, 20132013-02-11
On Mon, 11 Feb 2013 13:42:01 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>Hi, all--I'm looking for a curve tracer. Ideally it would be >USB-powered, and come with software that would make plots and generate >data files. Nothing too fancy, just I_C and I_B vs V_CE and V_BE, and >the equivalent for FETs. A plus would be automatic computation of beta, >V_GSth, Early voltage, and even some of the DC SPICE parameters like >emitter and base resistance. > >It would be especially nice if it could measure gate current with a >resolution of a picoamp or less. > >Any suggestions? > >Cheers > >Phil HobbsIt should do capacitance too. I've been wanting to do one of these... I might if nobody else does it. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●February 11, 20132013-02-11
John Larkin <jlarkin@highlandtechnology.com> writes:> On Mon, 11 Feb 2013 13:42:01 -0500, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >>Hi, all--I'm looking for a curve tracer. Ideally it would be >>USB-powered, and come with software that would make plots and generate >>data files. Nothing too fancy, just I_C and I_B vs V_CE and V_BE, and >>the equivalent for FETs. A plus would be automatic computation of beta, >>V_GSth, Early voltage, and even some of the DC SPICE parameters like >>emitter and base resistance. >> >>It would be especially nice if it could measure gate current with a >>resolution of a picoamp or less. >> >>Any suggestions? >> >>Cheers >> >>Phil Hobbs > > It should do capacitance too. I've been wanting to do one of these... > I might if nobody else does it.Cool project for someone. -- John Devereux
Reply by ●February 11, 20132013-02-11
On 02/11/2013 04:03 PM, Joerg wrote:> Phil Hobbs wrote: >> Hi, all--I'm looking for a curve tracer. Ideally it would be >> USB-powered, and come with software that would make plots and generate >> data files. Nothing too fancy, just I_C and I_B vs V_CE and V_BE, and >> the equivalent for FETs. A plus would be automatic computation of beta, >> V_GSth, Early voltage, and even some of the DC SPICE parameters like >> emitter and base resistance. >> >> It would be especially nice if it could measure gate current with a >> resolution of a picoamp or less. >> >> Any suggestions? >> > > Quite a niche market, that probably gets expensive: > > http://c418683.r83.cf2.rackcdn.com/uploaded/BL_765670_e_ver2.pdf >I found one at Photonics West for $169, distributed by Ana Tek. (For Canadians with long memories, this isn't the power supply manufacturer from Vancouver.) http://www.anatekcorp.com/test%20equipment.htm . Doesn't seem to do gate leakage, though. The optimal combination might be one of these plus a bandaid box made of op amps, to increase the measured current by, say, 1E7 times to make the FET look more like a BJT. That would confuse its built-in functions completely, I expect. What I'm using now is a cast-aluminum Bud box with op amps in it, that generates a nice ramp for V_GS, has a knob for V_DS, and has TIAs for I_G and I_D. Works well but is a bit of a pain, and has no data acq. I could put something like that on the front of a Labjack (Joerg's fave). That would be a bit more dough, but I'll be needing to do a half dozen protos with data acquisition in the next few weeks anyway, so I can amortize the s/w labour over my gizmo and the client's work. (I hate charging clients for building libraries.) A standalone unit would be a lot nicer though. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●February 11, 20132013-02-11
On 02/11/2013 04:09 PM, John Larkin wrote:> On Mon, 11 Feb 2013 13:42:01 -0500, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> Hi, all--I'm looking for a curve tracer. Ideally it would be >> USB-powered, and come with software that would make plots and generate >> data files. Nothing too fancy, just I_C and I_B vs V_CE and V_BE, and >> the equivalent for FETs. A plus would be automatic computation of beta, >> V_GSth, Early voltage, and even some of the DC SPICE parameters like >> emitter and base resistance. >> >> It would be especially nice if it could measure gate current with a >> resolution of a picoamp or less. >> >> Any suggestions? >> >> Cheers >> >> Phil Hobbs > > It should do capacitance too. I've been wanting to do one of these... > I might if nobody else does it. > >Capacitance would be nice, especially if it were done at medium frequency a la Boonton, so that you could put in whatever ferrite beads and stuff you needed to keep the DUT from oscillating. For my biochip front ends, I measure input capacitance by finding the gain with a 1-pF input cap and a 100-pF, then looking at the change in gain to find the voltage divider ratio. Not 100% kosher unless the feedback capacitance is super low, but it has to be if one wants <~ 1 pF input capacitances in a built-up circuit. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●February 11, 20132013-02-11
Phil Hobbs wrote:> On 02/11/2013 04:03 PM, Joerg wrote: >> Phil Hobbs wrote: >>> Hi, all--I'm looking for a curve tracer. Ideally it would be >>> USB-powered, and come with software that would make plots and generate >>> data files. Nothing too fancy, just I_C and I_B vs V_CE and V_BE, and >>> the equivalent for FETs. A plus would be automatic computation of beta, >>> V_GSth, Early voltage, and even some of the DC SPICE parameters like >>> emitter and base resistance. >>> >>> It would be especially nice if it could measure gate current with a >>> resolution of a picoamp or less. >>> >>> Any suggestions? >>> >> >> Quite a niche market, that probably gets expensive: >> >> http://c418683.r83.cf2.rackcdn.com/uploaded/BL_765670_e_ver2.pdf >> > I found one at Photonics West for $169, distributed by Ana Tek. (For > Canadians with long memories, this isn't the power supply manufacturer > from Vancouver.) > > http://www.anatekcorp.com/test%20equipment.htm . > > Doesn't seem to do gate leakage, though. The optimal combination might > be one of these plus a bandaid box made of op amps, to increase the > measured current by, say, 1E7 times to make the FET look more like a > BJT. That would confuse its built-in functions completely, I expect. > > What I'm using now is a cast-aluminum Bud box with op amps in it, that > generates a nice ramp for V_GS, has a knob for V_DS, and has TIAs for > I_G and I_D. Works well but is a bit of a pain, and has no data acq. > > I could put something like that on the front of a Labjack (Joerg's > fave). That would be a bit more dough, but I'll be needing to do a half > dozen protos with data acquisition in the next few weeks anyway, so I > can amortize the s/w labour over my gizmo and the client's work. (I > hate charging clients for building libraries.) > > A standalone unit would be a lot nicer though. >Hey, doesn't one of your kids want to get his hands dirty with some software work? If you charge the client a lower rate for that work he could still sock away a lot of money towards his first souped-up TransAm with mag wheels and all that :-) If it's any comfort I'll have to design some radio circuitry soon and build (yuck ...) several prototypes. Will use Labjacks again, mainly because those come with a copy of a SCADA software to make life a bit easier for SW-challenged guys like me. I just hope the garage ain't so cold anymore once I get to do the boxes. But I don't envy you guys out there right now, had a teleconference this morning and one guy is on Long Island, snowed in. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●February 11, 20132013-02-11
On 02/11/2013 05:14 PM, Joerg wrote:> Phil Hobbs wrote: >> On 02/11/2013 04:03 PM, Joerg wrote: >>> Phil Hobbs wrote: >>>> Hi, all--I'm looking for a curve tracer. Ideally it would be >>>> USB-powered, and come with software that would make plots and generate >>>> data files. Nothing too fancy, just I_C and I_B vs V_CE and V_BE, and >>>> the equivalent for FETs. A plus would be automatic computation of beta, >>>> V_GSth, Early voltage, and even some of the DC SPICE parameters like >>>> emitter and base resistance. >>>> >>>> It would be especially nice if it could measure gate current with a >>>> resolution of a picoamp or less. >>>> >>>> Any suggestions? >>>> >>> >>> Quite a niche market, that probably gets expensive: >>> >>> http://c418683.r83.cf2.rackcdn.com/uploaded/BL_765670_e_ver2.pdf >>> >> I found one at Photonics West for $169, distributed by Ana Tek. (For >> Canadians with long memories, this isn't the power supply manufacturer >> from Vancouver.) >> >> http://www.anatekcorp.com/test%20equipment.htm . >> >> Doesn't seem to do gate leakage, though. The optimal combination might >> be one of these plus a bandaid box made of op amps, to increase the >> measured current by, say, 1E7 times to make the FET look more like a >> BJT. That would confuse its built-in functions completely, I expect. >> >> What I'm using now is a cast-aluminum Bud box with op amps in it, that >> generates a nice ramp for V_GS, has a knob for V_DS, and has TIAs for >> I_G and I_D. Works well but is a bit of a pain, and has no data acq. >> >> I could put something like that on the front of a Labjack (Joerg's >> fave). That would be a bit more dough, but I'll be needing to do a half >> dozen protos with data acquisition in the next few weeks anyway, so I >> can amortize the s/w labour over my gizmo and the client's work. (I >> hate charging clients for building libraries.) >> >> A standalone unit would be a lot nicer though. >> > > Hey, doesn't one of your kids want to get his hands dirty with some > software work? If you charge the client a lower rate for that work he > could still sock away a lot of money towards his first souped-up TransAm > with mag wheels and all that :-) >Brr. My son is _not_ "going to drive me to drinkin'" if I can help it, but anyway that wouldn't be his style. He's busy writing Arm Cortex M3 firmware at the moment, but since he's learning C at the same time, he isn't fast at it yet. (He did get a task switcher working, using a linked list of tasks handled by the systick interrupt handler.)> If it's any comfort I'll have to design some radio circuitry soon and > build (yuck ...) several prototypes. Will use Labjacks again, mainly > because those come with a copy of a SCADA software to make life a bit > easier for SW-challenged guys like me. I just hope the garage ain't so > cold anymore once I get to do the boxes. But I don't envy you guys out > there right now, had a teleconference this morning and one guy is on > Long Island, snowed in. >My wife and I spent a very pleasant hour or so on Saturday, digging out from 18-24 inches of pretty light snow. It was heavier near the road where the plough had been, of course, but no worries. Bright sunshine, well above freezing, sun melting the last little bits of snow left behind on the driveway. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
