I'm looking for one or two of these arrays for a small home project. Yes, I know they're available from China on eBay, but I'd much rather find a couple of vintage (and authentic and working) parts from someone's bin. There may be other parts that are suitable, but this is the only array I remember where all the devices are fully pinned-out. This requirement is important and excludes LM3046 and similar parts. Device matching needn't be perfect as I can trim it out. The array needs to be junction isolated to ensure that all devices will be at as nearly the same temperature as possible - the old Harris HFA3127 is right out due to its use of dielectric isolation. Yes, I know it's a high-frequency array and I need to watch out for parasitic oscillations. I've used these before in my day job, but none remain in the parts drawers :( I'm building a temperature compensating gizmo that needs a current cuber, something I can in theory do as a translinear circuit with 5 transistors, a cheap quad op-amp, and some passives. The process I'm dealing with is exponential but the cubic function is gives a surprisingly good approximation to what I need over my limited temperature range. I'd like to start out with a translinear cuber because translinear is cool, but if that proves troublesome I can use the same array to make a copy of the AD538 - this would allow me to get a non-integer power that would be even more accurate. The real AD538 is still available but seems excessive at over $50 each in small quanitities. Hmm, I wonder if I can build a 538 clone with a less exotic array like a 3046... Thanks for any pointers. Hint - Remove the HAM to reply by email.
Domestic US source for small quantity of CA3127 transistor array?
Started by ●August 16, 2016
Reply by ●August 16, 20162016-08-16
On Tue, 16 Aug 2016 07:28:09 -0400 Steve Goldstein <sgoldHAM@alum.mit.edu> wrote in Message id: <9es5rbhnhrbik8vqv0i5ahqhulhvodh6vb@4ax.com>:>I'm looking for one or two of these arrays for a small home project. >Yes, I know they're available from China on eBay, but I'd much rather >find a couple of vintage (and authentic and working) parts from >someone's bin.[snip] http://www.oemstrade.com/search/CA3127 Looks like there's stock out there in small quantities. I've had good success with Quest in the past, and Rochester Electronics is reputable.
Reply by ●August 16, 20162016-08-16
On Tuesday, August 16, 2016 at 7:28:21 AM UTC-4, Steve Goldstein wrote:> I'm looking for one or two of these arrays for a small home project. > Yes, I know they're available from China on eBay, but I'd much rather > find a couple of vintage (and authentic and working) parts from > someone's bin. > > There may be other parts that are suitable, but this is the only array > I remember where all the devices are fully pinned-out. This > requirement is important and excludes LM3046 and similar parts. Device > matching needn't be perfect as I can trim it out. The array needs to > be junction isolated to ensure that all devices will be at as nearly > the same temperature as possible - the old Harris HFA3127 is right out > due to its use of dielectric isolation. > > Yes, I know it's a high-frequency array and I need to watch out for > parasitic oscillations. I've used these before in my day job, but > none remain in the parts drawers :( > > I'm building a temperature compensating gizmo that needs a current > cuber, something I can in theory do as a translinear circuit with 5 > transistors, a cheap quad op-amp, and some passives. The process I'm > dealing with is exponential but the cubic function is gives a > surprisingly good approximation to what I need over my limited > temperature range. I'd like to start out with a translinear cuber > because translinear is cool, but if that proves troublesome I can use > the same array to make a copy of the AD538 - this would allow me to > get a non-integer power that would be even more accurate. The real > AD538 is still available but seems excessive at over $50 each in small > quanitities. > > Hmm, I wonder if I can build a 538 clone with a less exotic array like > a 3046... > > Thanks for any pointers. > > Hint - Remove the HAM to reply by email.I've got a tube of these (5 x NPN, RCA)-- http://www.brown.edu/Departments/Engineering/Courses/En162/DataSheets/ca3083.pdf Good enough? Cheers, James Arthur
Reply by ●August 16, 20162016-08-16
On Tuesday, August 16, 2016 at 7:28:21 AM UTC-4, Steve Goldstein wrote:> I'm looking for one or two of these arrays for a small home project. > Yes, I know they're available from China on eBay, but I'd much rather > find a couple of vintage (and authentic and working) parts from > someone's bin. > > There may be other parts that are suitable, but this is the only array > I remember where all the devices are fully pinned-out. This > requirement is important and excludes LM3046 and similar parts. Device > matching needn't be perfect as I can trim it out. The array needs to > be junction isolated to ensure that all devices will be at as nearly > the same temperature as possible - the old Harris HFA3127 is right out > due to its use of dielectric isolation. > > Yes, I know it's a high-frequency array and I need to watch out for > parasitic oscillations. I've used these before in my day job, but > none remain in the parts drawers :( > > I'm building a temperature compensating gizmo that needs a current > cuber, something I can in theory do as a translinear circuit with 5 > transistors, a cheap quad op-amp, and some passives. The process I'm > dealing with is exponential but the cubic function is gives a > surprisingly good approximation to what I need over my limited > temperature range. I'd like to start out with a translinear cuber > because translinear is cool, but if that proves troublesome I can use > the same array to make a copy of the AD538 - this would allow me to > get a non-integer power that would be even more accurate. The real > AD538 is still available but seems excessive at over $50 each in small > quanitities. > > Hmm, I wonder if I can build a 538 clone with a less exotic array like > a 3046... > > Thanks for any pointers. > > Hint - Remove the HAM to reply by email.https://octopart.com/search?q=CA3127 You could buy a couple of cheaper multipliers from AD. George H.
Reply by ●August 16, 20162016-08-16
On 08/16/2016 07:28 AM, Steve Goldstein wrote:> I'm looking for one or two of these arrays for a small home project. > Yes, I know they're available from China on eBay, but I'd much rather > find a couple of vintage (and authentic and working) parts from > someone's bin. > > There may be other parts that are suitable, but this is the only array > I remember where all the devices are fully pinned-out. This > requirement is important and excludes LM3046 and similar parts. Device > matching needn't be perfect as I can trim it out. The array needs to > be junction isolated to ensure that all devices will be at as nearly > the same temperature as possible - the old Harris HFA3127 is right out > due to its use of dielectric isolation. > > Yes, I know it's a high-frequency array and I need to watch out for > parasitic oscillations. I've used these before in my day job, but > none remain in the parts drawers :( > > I'm building a temperature compensating gizmo that needs a current > cuber, something I can in theory do as a translinear circuit with 5 > transistors, a cheap quad op-amp, and some passives. The process I'm > dealing with is exponential but the cubic function is gives a > surprisingly good approximation to what I need over my limited > temperature range. I'd like to start out with a translinear cuber > because translinear is cool, but if that proves troublesome I can use > the same array to make a copy of the AD538 - this would allow me to > get a non-integer power that would be even more accurate. The real > AD538 is still available but seems excessive at over $50 each in small > quanitities. > > Hmm, I wonder if I can build a 538 clone with a less exotic array like > a 3046... > > Thanks for any pointers. > > Hint - Remove the HAM to reply by email. >I think you overestimate the thermal resistance of the oxide insulation. SOI is typically 200 nm of oxide (~1 W/m/K), so for a (say) 10-mil device, it adds only about 3 W/m/K between devices, which is about 1% of the thermal resistance of a SOT-packaged device. 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 ●August 16, 20162016-08-16
On 08/16/2016 11:04 AM, George Herold wrote:> On Tuesday, August 16, 2016 at 7:28:21 AM UTC-4, Steve Goldstein wrote: >> I'm looking for one or two of these arrays for a small home project. >> Yes, I know they're available from China on eBay, but I'd much rather >> find a couple of vintage (and authentic and working) parts from >> someone's bin. >> >> There may be other parts that are suitable, but this is the only array >> I remember where all the devices are fully pinned-out. This >> requirement is important and excludes LM3046 and similar parts. Device >> matching needn't be perfect as I can trim it out. The array needs to >> be junction isolated to ensure that all devices will be at as nearly >> the same temperature as possible - the old Harris HFA3127 is right out >> due to its use of dielectric isolation. >> >> Yes, I know it's a high-frequency array and I need to watch out for >> parasitic oscillations. I've used these before in my day job, but >> none remain in the parts drawers :( >> >> I'm building a temperature compensating gizmo that needs a current >> cuber, something I can in theory do as a translinear circuit with 5 >> transistors, a cheap quad op-amp, and some passives. The process I'm >> dealing with is exponential but the cubic function is gives a >> surprisingly good approximation to what I need over my limited >> temperature range. I'd like to start out with a translinear cuber >> because translinear is cool, but if that proves troublesome I can use >> the same array to make a copy of the AD538 - this would allow me to >> get a non-integer power that would be even more accurate. The real >> AD538 is still available but seems excessive at over $50 each in small >> quanitities. >> >> Hmm, I wonder if I can build a 538 clone with a less exotic array like >> a 3046... >> >> Thanks for any pointers. >> >> Hint - Remove the HAM to reply by email. > > https://octopart.com/search?q=CA3127 > > You could buy a couple of cheaper multipliers from AD. > > George H. >A one-quadrant cuber only needs three transistors, so how about a MAT14? See e.g. http://electrooptical.net/www/sed/CubicPolynomial.pdf 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 ●August 16, 20162016-08-16
"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message news:dbd2b3df-f159-8b0f-5d42-3aabe65eab18@electrooptical.net...> I think you overestimate the thermal resistance of the oxide insulation. > SOI is typically 200 nm of oxide (~1 W/m/K), so for a (say) 10-mil > device, it adds only about 3 W/m/K between devices, which is about 1% of > the thermal resistance of a SOT-packaged device.Yabbut, ain't that Al2O3, single crystal because it conveniently aligns with silicon's lattice? Which is pretty conductive, not quite as good as Si, but suffice it to say -- good enough you can't even tell the difference (even less so than the above case!). Or it's not SOI like I've heard it done, which, I haven't seen a drawing of the part in question, so I have no idea. Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: http://seventransistorlabs.com
Reply by ●August 16, 20162016-08-16
>Yabbut, ain't that Al2O3, single crystal because it conveniently aligns with >silicon's lattice? Which is pretty conductive, not quite as good as Si, but >suffice it to say -- good enough you can't even tell the difference (even >less so than the above case!).>Or it's not SOI like I've heard it done, which, I haven't seen a drawing of >the part in question, so I have no idea.Ah, Grasshopper, you conflate SOI with SOS. ;) Silicon on Sapphire is an uber-expensive process once used by (iirc) HP and almost nobody else. SOI is insulated with SiO2, either by wafer bonding followed by a lot of grinding and polishing (old IBM), or by implanting some gross amount of oxygen and then annealing to make the oxygen precipitates coalesce into an insulating layer (SIMOX). SOI parts are almost universally made on SIMOX-type wafers AFAIK. Cheers Phil Hobbs
Reply by ●August 16, 20162016-08-16
"Phil Hobbs" <pcdhobbs@gmail.com> wrote in message news:d25ca1fa-bef5-4826-b658-10ab3379a004@googlegroups.com...> Ah, Grasshopper, you conflate SOI with SOS. ;)<snip> Ah, yeah... that sounds much easier (and, better than "shit on [a] shingle"). :o) Though now that you mention it... Isn't single crystal Al2O3 pretty common? Like, sapphire plates are used for checkout scanners because it's scratch resistant (or at least, that was what I had heard, unless they use a very good scratch-resistant coating now)? Or is it that it has to be precisely axially aligned, low defect, and, ah, just as high purity as the Si that goes on top of it? Two facts come to mind... Al2O3 has good ionic solubility and mobility (at only slightly elevated temperatures) for Na... which is also mobile in SiO2, leading to charge motion in gate oxides, and really shitty CMOS... Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: http://seventransistorlabs.com
Reply by ●August 16, 20162016-08-16
On Tue, 16 Aug 2016 12:07:53 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 08/16/2016 07:28 AM, Steve Goldstein wrote: >> I'm looking for one or two of these arrays for a small home project. >> Yes, I know they're available from China on eBay, but I'd much rather >> find a couple of vintage (and authentic and working) parts from >> someone's bin. >> >> There may be other parts that are suitable, but this is the only array >> I remember where all the devices are fully pinned-out. This >> requirement is important and excludes LM3046 and similar parts. Device >> matching needn't be perfect as I can trim it out. The array needs to >> be junction isolated to ensure that all devices will be at as nearly >> the same temperature as possible - the old Harris HFA3127 is right out >> due to its use of dielectric isolation. >> >> Yes, I know it's a high-frequency array and I need to watch out for >> parasitic oscillations. I've used these before in my day job, but >> none remain in the parts drawers :( >> >> I'm building a temperature compensating gizmo that needs a current >> cuber, something I can in theory do as a translinear circuit with 5 >> transistors, a cheap quad op-amp, and some passives. The process I'm >> dealing with is exponential but the cubic function is gives a >> surprisingly good approximation to what I need over my limited >> temperature range. I'd like to start out with a translinear cuber >> because translinear is cool, but if that proves troublesome I can use >> the same array to make a copy of the AD538 - this would allow me to >> get a non-integer power that would be even more accurate. The real >> AD538 is still available but seems excessive at over $50 each in small >> quanitities. >> >> Hmm, I wonder if I can build a 538 clone with a less exotic array like >> a 3046... >> >> Thanks for any pointers. >> >> Hint - Remove the HAM to reply by email. >> > >I think you overestimate the thermal resistance of the oxide insulation. > SOI is typically 200 nm of oxide (~1 W/m/K), so for a (say) 10-mil >device, it adds only about 3 W/m/K between devices, which is about 1% of >the thermal resistance of a SOT-packaged device. > >Cheers > >Phil HobbsNearly all my design activities for the past 10+ years have been with dielectrically isolated processes. The earlier processes had device thermal resistances of several thousand degrees per K, the newest one is even higher. I'd rather not have to even worry about it. Thanks Steve
