/etc... Amplifiers & Other Linear

Forum Post: RE: OP AMP Differentiate 1 mV

nikhil vv — Wed, 19 Jun 2013 04:27:00 GMT

Sir,

Thank you very much for your support. I am very much happy for your comments and co operation.

It made a clear image in my testing circuit.

Thanks again for sharing your valuable time.....

Regards,

Nikhil

Forum Post: RE: LM397 absolute maximum spec for Vout?

Paul Grohe — Tue, 18 Jun 2013 17:50:00 GMT

Hello Roman,

Yes. There are clamps to ground on all the input and output pins.

Again, I have pinged the designers/process people to get this info.

The Abs Max is 30V, so the only guarantee would be that it would not clamp at 30V, but it may clamp at 31V, or 32V, or...

I just cannot feel comfortable giving an "OK" for 6V over the Abs Max.

If you need 36V, then use the original LM393-N dual version as these do NOT have ESD clamps and are spec'd to 36V.

Regards,

Forum Post: RE: ISO122 Supply voltages

Bruce Trump — Sun, 16 Jun 2013 16:54:00 GMT

Nilesh,

The power supply voltage does not affect the isolation voltage capability of the ISO122. The isolation voltage rating is determined by the integrity of the insulating materials used between the input and output sections.

The power supply voltages you propose will not allow the ISO122 to pass a signal. The minimum rated supply is +/-4.5V (or 9V, single supply). Signal swing capability with this minimum supply would be very limited.

Regards, Bruce.

Forum Post: RE: Current shunt monitor DIP package

Bruce Trump — Sat, 15 Jun 2013 11:44:00 GMT

Gehan,

I am not aware of any. You may want to consider the approach shown in this blog:

Breadboarding with Micro-Packages—Ouch!

Regards. Bruce.

Forum Post: RE: ISO122JP problem

Thomas Kuehl — Thu, 13 Jun 2013 15:41:00 GMT

Hi Hiam,

Your implementation of the ISO122J is straightforward and I don't find any problems with its portion of the circuit schematic. The problem you are chasing is one as if the circuit is operating with a gain greater than 1 V/V, producing a higher output voltage than expected for a given input voltage.

When you observe this unexpectedly high output voltage are you monitoring the output of the ISO122J, test point P141, or the AMP OUT point? If the output voltage at P141 is too high, then the ISO122J is suspect and you should try a different device in its place. If the output voltage is okay at P141 and too high at AMP OUT, then something is not working correctly in the OP77 circuit. Its gain should be 1 V/V within its pass-band.

Re-check your supply voltages on ISO122J power supply pins and also the OP77. You might want to do so with a DSO. That way you can observe the input signal at the ISO122J input, output, power supply lines, and OP77 output. Make sure you are not seeing any oscillation, or anything else unexpected.

Regards, Thomas

PA - Linear Applications Engineering

Forum Post: RE: LMV641

Vladimir Naumenkov — Thu, 13 Jun 2013 06:02:00 GMT

Dear Mike

Thank you

Yours sincerely

Vladimir Naumenkov

www.agat.by

Forum Post: RE: LMV358 Upgrade

Rustin Schroeder — Mon, 10 Jun 2013 19:32:00 GMT

Part looks great. Thanks.

Forum Post: RE: LMC7111 same pinout replacement?

Paul Grohe — Thu, 06 Jun 2013 16:20:00 GMT

Hi Paul,

Yes...The LMC7111 and LMC7101 suffer from "Early Adopter Syndrome". They were among the first op-amps introduced in the SOT-23 package many moons ago, and in those wild-west days, the pinouts had not "standardized" yet. Combined with a positive die attach, it got stuck with the unusual "reversed supply" pinout.

The LMC7111 is the low power (50KHz, 25uA) version of the LMC7101 (1MHz, 500uA). So if you need about 1MHz, then the LMC7101 is the natural replacement.

The TLV2711, 2721 and TLV2731 also have the same pinout. The 2711 and 2721 fill the gaps between the 7111 and 7101. The TLV2731 is 2MHz GBW, so that would be your "fastest" option. Note that the TLV's are 10V vs the LMC's 15V max supply.

Regards,

Forum Post: RE: INA226 slave address

hisakichi kobayashi — Thu, 06 Jun 2013 06:46:00 GMT

Dear Mr. Edward Mullins

Thank you for your reply. Realy Thanks.
The cause of incorrect discernment was found.
It was a place different from INA226.

Best regards

Hisa kobayashi

Forum Post: RE: INA168 input voltage range (measure inputs from 0 to 2,7v)

Edward Mullins — Thu, 06 Jun 2013 00:20:00 GMT

Hi,

Thank you for your question on INA168...the INA168 will require a minimum of 2.7V to operate properly so for your application of CMV from 0 to 2.7V the INA168 is not the right choice. Please have a look at the INA210 family...it has a CMV range from -0.3V to 26V. There may be other design considerations that you have like accuracy, bandwidth, gain, etc, so if you have additional questions, please reply back to this thread with the additional information and questions.

Forum Post: RE: Input impedance of OPA360

Jeffery Pfarr — Wed, 05 Jun 2013 21:25:00 GMT

Jaden,

TINA-TI had a model for the OPA360, so I ran an AC Analysis transfer function for Iin/ Vin (see attached screenshot) then inverted to get Vin/Iin = Zin. At 10 Hz, Zin is around 562 M ohm and at 10 MHz, Zin is around 1k ohms. I think this looks about right but is model dependent.

The LMH 6704 does not have a TINA-TI model but the input is specified to be 1 M ohm in parallel with 1 pF typical so this covers the gain of +1 and +2 cases. For the gain of -1 case, the input impedance is just the input resistor value of 465 ohms (likely with 1 pF cap to GND).

Forum Post: RE: 15kV ESD Op-Amp?

Bruce Trump — Tue, 04 Jun 2013 14:39:00 GMT

Audi,

I'm not aware of any of our op amps meeting a 15kV ESD rating. Keep in mind that these ratings are a measure of ESD tolerance of bare parts during handling and assembly. Performance on a circuit board is generally much better. With additional measures, including added protection devices, inputs can be made quite robust. This is true for logic devices as well as op amps. See this blog for some background...

ESD… Zapp! protecting circuits and systems from damage and functional failures

Regards, Bruce.

Forum Post: RE: OPA454 E/D logic connection

Arthur Elsenaar — Sun, 02 Jun 2013 14:55:00 GMT

This works absolutely great!

Thanks!

Forum Post: RE: Current Limiting in 4-20mA loop

greenja — Thu, 30 May 2013 22:54:00 GMT

Collin,

If I showed you the circuit, it would greatly impact the sales of the entire XTR11x product line. The last thing we developers need is for someone with your skills, knowledge and expertise entering into the freelance market! I'll keep it under my hat for now :)

Thanks,

Forum Post: RE: How to stabilize OPA551/OPA551 with capacitive load?

Tim Green1 — Thu, 30 May 2013 15:58:00 GMT

See attached for OPA551 with 22uF cap load.

Forum Post: RE: OPA445 : Offset trim pin

Bruce Trump — Thu, 30 May 2013 11:41:00 GMT

Gilles,

These pins should be left floating (no connection). See this blog for more background on trim pins...

Where are the Trim Pins? some background on offset voltage trim pins

Regards, Bruce.

Forum Post: RE: LMH6629 Evaluation Board - strange output signal

Guglielmo Sirna — Wed, 29 May 2013 10:14:00 GMT

Thanks. Please considered this answered

Forum Post: RE: problem with common ground

Bruce Trump — Tue, 28 May 2013 12:03:00 GMT

Akhilesh,

I don't see any problem in connecting these two ground unless the power supplies are interconnected in a way that you have not explained. The two grounds will assume the same potential when they are connected.

Regards, Bruce

Forum Post: RE: XTR 117

Purushottam Pawar — Tue, 28 May 2013 06:34:00 GMT

Thanks for the advice Bruce!!!!!

Please have a look on attached schematic.

I do have another XTR 117. I will try this with another XTR 117 and your suggestions.

Thanks again for your kind support!!!

Regards,

Paddy

Forum Post: RE: OPA551 common mode levels and noise predictions

Bruce Trump — Mon, 27 May 2013 11:43:00 GMT

Bjarke,

The input stage of the OPA551 is cascoded, meaning that the input transistors have virtually the same operating voltage conditions at any point within the common-mode range. I don't expect any significant change in noise at your operating point.

I expect voltage noise to increase somewhat with temperature, perhaps by approximately 25% or so at the high end of temperature range. Current noise will rise more, increasing by about 3x for each 10k rise in temperature.

Regards, Bruce