Post by thread:[EE] 50V Equivalent of LM324?

On Mon, 6 Dec 2004 15:42:51 -0800 (PST), you wrote: >Anyone know of a 50V or 60V quad op amp that has the same pin out as an >LM324? Some of the TI TLE range got to 40V but above that you are getting into expensive specialist territory, and may find it a lot cheaper to use an external output driver for the HV ____________________________________________

That's what I'm afraid of! Our board is all set for LM324. We generally do a 0-10V output, but we've got a customer that wants 0-45. Discrete components on 48 outputs on a board not designed for those components will be fun! Harold {Quote hidden}> On Mon, 6 Dec 2004 15:42:51 -0800 (PST), you wrote: > >>Anyone know of a 50V or 60V quad op amp that has the same pin out as an >>LM324? > > Some of the TI TLE range got to 40V but above that you are getting into > expensive specialist > territory, and may find it a lot cheaper to use an external output driver > for the HV > > > ______________________________________________

At 04:58 PM 12/6/2004 -0800, you wrote: >That's what I'm afraid of! Our board is all set for LM324. We generally do >a 0-10V output, but we've got a customer that wants 0-45. Discrete >components on 48 outputs on a board not designed for those components will >be fun! > >Harold You can get 44V abs. max, but even then they are expensive. Last time I had to do this, I put a discrete component booster on the output for +/-100V output swing into a capacitive load. The loop was compensated and closed around the booster so that DC accuracy was unaffected. Bandwidth was okay for the application (audio range of frequencies). Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" spam_OUTspeffTakeThisOuTinterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com ____________________________________________

> Anyone know of a 50V or 60V quad op amp that has the same pin out as an > LM324? No. but the question is, why do you want it? If you want to sense levels at 60v they can be translated down to within 324 range without too much degradation. If you want to drive the output at 60v you can easily enough add a simple output stage to the 324 to do so. What is the application? RM ____________________________________________

if the lm324 isn't surface mounted, it should be easy enough to make a small board with surface mount parts (possibly fitting vertically on the main board) to replace the lm324. if it is surface mount already it's still possible, even if it has to be a horizontal board and would be less effort than redesigning the main board depending on vibration and such in which case i'd say attach the driver board with silicon rubber. alternatively use a separate box to convert the outputs to a higher voltage, that way the main board is still your' standard part and easier to maintain and replace, i.e. build a separate box that converts the 0-10V to the higher voltage the client wants. in any case you should definitely be charging a lot for this design change! > On Mon, 6 Dec 2004 15:42:51 -0800 (PST), you wrote: > > >Anyone know of a 50V or 60V quad op amp that has the same pin out as an > >LM324? ------ -- Why is this man in the White House? The majority of Americans did not vote for him. Why is he there? And I tell you this morning that he's in the White House because God put him there for a time such as this: Lt Gen William Boykin, speaking of G. W. Bush, New York Times, 17 October 2003 = God gave the savior to the German people. We have faith, deep and unshakeable faith, that he was sent to us by God to save Germany. Hermann Goering, speaking of Hitler ____________________________________________

The application is getting a 0 to -45VDC output from the MTX-DE48 at http://www.dovesystems.com . As it is, I can get about 0 to +30V or 0 to -30V out of it (48 channels of it). Doing a discrete output stage seems like it'd take 3 or 4 transistors per output. Sure would be nice to be on a chip! Harold {Quote hidden}>> Anyone know of a 50V or 60V quad op amp that has the same pin out as an >> LM324? > > No. but the question is, why do you want it? > If you want to sense levels at 60v they can be translated down to within > 324 > range without too much degradation. If you want to drive the output at 60v > you can easily enough add a simple output stage to the 324 to do so. What > is > the application? > > RM > > ______________________________________________

At 09:09 PM 12/6/2004 -0800, you wrote: >The application is getting a 0 to -45VDC output from the MTX-DE48 at >http://www.dovesystems.com . As it is, I can get about 0 to +30V or 0 to >-30V out of it (48 channels of it). Doing a discrete output stage seems >like it'd take 3 or 4 transistors per output. Sure would be nice to be on >a chip! > >Harold MC33174 quad op-amps are cheap and will work up to 44V supply voltage guaranteed. That's getting pretty close to your stated requirement. Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" .....speffKILLspam@spam@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com ____________________________________________

> The application is getting a 0 to -45VDC output from the MTX-DE48 > at http://www.dovesystems.com . As it is, I can get about 0 to +30V > or 0 to -30V out of it (48 channels of it). Doing a discrete output > stage seems like it'd take 3 or 4 transistors per output. Sure > would be nice to be on a chip! Discrete transistors still might be cheaper than high voltage op-amps. As for high voltage op-amps, LM343 (obsolete now) comes to mind which was often used in mil equipment and can go upto +/- 34V. Its still available from surplus stores but is quite expensive. And its in a metal can package nowhere near being pin compatible to LM324. Come to think of it all op-amps that I've seen that go in the 60V range have been in metal can packaging. Shahid ____________________________________________

Another possibility is some audio power amp (driver) chip like the (discontinued) LM391, which can have +/-50V power supplies. Can anyone think of a currently available chip like this? Harold {Quote hidden}>> The application is getting a 0 to -45VDC output from the MTX-DE48 >> at http://www.dovesystems.com . As it is, I can get about 0 to +30V >> or 0 to -30V out of it (48 channels of it). Doing a discrete output >> stage seems like it'd take 3 or 4 transistors per output. Sure >> would be nice to be on a chip! > > Discrete transistors still might be cheaper than high voltage op-amps. > As for high voltage op-amps, LM343 (obsolete now) comes to mind which > was often used in mil equipment and can go upto +/- 34V. Its still > available from surplus stores but is quite expensive. And its in a metal > can package nowhere near being pin compatible to LM324. > > Come to think of it all op-amps that I've seen that go in the 60V range > have been in metal can packaging. > > Shahid > > ______________________________________________

On Mon, 6 Dec 2004, Harold Hallikainen wrote: > That's what I'm afraid of! Our board is all set for LM324. We generally do > a 0-10V output, but we've got a customer that wants 0-45. Discrete > components on 48 outputs on a board not designed for those components will > be fun! DMX ? Can you find out if the user can tolerate current sinking instead of voltage outputs ? Or look into single ended drive and pullup resistors ? Some open collector drivers go beyond 50V (uln2003 is 50V) and it is easy to put them in a feedback loop to include the opamp that drives them. Then add a pullup and you have hv drive. I would think about a daughterboard with 6x uln2003 and pullup and feedback resistors to the main board. And someone has to pay for this I suppose. Peter ____________________________________________