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TINA/Spice/OPA365-Q1: phase margin with driving capacitive load

September 21, 2018, 12:51 am
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Part Number:OPA365-Q1

Tool/software:TINA-TI or Spice Models

Dear all,

I simulated OPA365's phase margin with driving capacitive load (1nF) by TINA-TI.

But the phase margin was not so good. I know that we should have over 45 degree margin.

Please check following file that TINA result and TINA project file.

(Please visit the site to view this file)

(Please visit the site to view this file)

Could you teach me how to think about phase margin and how to control phase margin with driving capacitive load?

I referred to '9.1.1 Capacitive Loads' at data sheet, so I added series resistor at output line.

Now, I plan to input signal from hundreds [kHz] to several [MHz].

Best regards,

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LM339A: Response Time Question

September 21, 2018, 1:32 am
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Part Number:LM339A

Dear Team,

My schematic is as below figure.

From the scope, we saw there is about 300 ms response time between Vout and Vin.

If we change R5265 to 3.24K, Vin will be lower, and we can see the response time is only 200us.

Could you tell me what would be the available Vin+/-  offset voltage range?

Thank you. 

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OPA564: IFLAG and TFLAG behavior

September 21, 2018, 2:00 am
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Part Number:OPA564

TI,

I have constructed a circuit using the OPA564. Everything appears to be working fine, thus far --- but I am trying to validate the correct behavior of IFLAG and TFLAG.

First, for TFLAG I want to verify the correct behavior when used in conjunction with the E/S pin.

  • It appears that in my test circuit, TFLAG is high when E/S is pulled low (shutdown).
  • It is also high when E/S is high or unconnected, but has gone into thermal shutdown.

Thus, is it true that TFLAG is high whenever the device is shutdown?

Second, for IFLAG I want to verify that the correct behavior when in operation, with ILIM resistor 54.9k, ( Sets current to 24000/(54900+5000) = 0.40066778 A )

  • I cannot get the current to go over 0.300 A in the circuit when it is set in this way.
  • In the same scenario, I am seeing an immediate drop toward 0 A the higher and higher I try to push the current after this threshold.
  • I cannot trigger IFLAG for this reason.
  • It is variable however, if I use 20k in parallel with the 54.9k for example ~14.66k = 1.22A it falls off right around 1.05A.

How can I trigger IFLAG without it 'pinching off' right before the value?

Worth noting is that I am using a level shifting circuit on BOTH outputs. they are identical. for both IFLAG and TFLAG.

Vdig is +4.3V and VCC is +5V in this scenario. V- is -6V and V+ is +6V

Thanks

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LM339A: LM339A

September 21, 2018, 6:03 am
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Part Number:LM339A

Hello,

I has to use two of four comparators of a LM339AM in a safety function.

How are the internal circuits an components connectet and there are more components as in the pdf shown?

How strong is the insulation between the comparators?

Thank you in advance.

Thomas Heine

0049 30 7622 3732

Germany, 12266 Berlin

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OPA2132: DC Servo OpAmp Replacement in Technics Amplifier

September 21, 2018, 2:55 pm
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Part Number:OPA2132

Hello,

I need to replace the operational opamps in my amplifier due to transistor failure, and --54v went through -17v rails.

DC Servo circuit is below its a new class at Technics SU-V9 from the 1980s. The old part was AN6552 which is gone and modern replacement is RC4558   (voltage is 15+/-). But maybe the OPA2134 or OPA2132 or a better suited Opamp for the circuit would be best

Thank you

Best Regards

Sam

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LMH5401: LMH5401 input and output common mode voltage under single supply

September 21, 2018, 7:58 pm
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Part Number:LMH5401

Hello all,

My customer is now looking for a differential amplifier for oscilloscope project to drive ADC.

The specific requirements for amplifiers lists below:

 1. 12dB gain, output amplitude 2Vpp and bandwidth > 1.2GHz (load 200 omega);

 2. support 1.25V common mode input and 1.25V common mode output;

I want to promote LMH5401.  From datasheet it says that LMH5401 can support single supply, but I concern that the common mode voltage cannot meet their requirement.

If not ,would you please recommend other sockets?

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TINA/Spice/INA139: Read bipolar current over both positive and negative range.

September 21, 2018, 11:40 pm
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Part Number:INA139

Tool/software:TINA-TI or Spice Models

Hello,

I'm following up on a previous inquiry related to the INA139 and simulations in TI-TINA.

I'm exploring the device again for another project, but I am once again having issues with the INA139's simulation models.

---

The intention is to use two INA139's in a bipolar configuration to measure the bidirectional current across a range of +12 V to -12 V. I realize that the common-mode range must be observed when dealing with the current measurement, thus I have elected to attach "GND" of the INA139 to the -12V rail, and Power the "V+" of the INA139 from the +12V rail.

This should keep the common mode between 2.7V and 40V referenced to the negative rail.

What I would like to do is feed this value into a difference amplifier similar to 8.2.5 Bipolar Current Measurement Using a Differential Input of the A/D Converter in the INA139 datasheet, but I cannot see to get this working in my simulations. I am using an OPA197 as the amplifier.

Any help would be appreciated.

Thanks,

 

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OPA4172: Audio signal bleeding into other channels (QUAD microphone preamp)

September 22, 2018, 3:05 am
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Part Number:OPA4172

Hey

I've created my first PCB design 
using the design from http://www.ti.com/tool/TIPD181 as a basisfor the quad channel preamp OPA4172.
circuit wire up:
https://imgur.com/1e0fYMw

Pcb Design without ground plane showing:
https://imgur.com/DmMtIYb


Pcb with ground plane:
https://imgur.com/5kgW2RJ 

My issue is that all my inputs (mic 1-4) are all showing up across all outputs. Eg; mic 1 will show at all outputs, 2 at all outputs etc etc.
I've tried making another circuit with no ground plane in the case that the PCB tracks were crossing with the outputs but it sounds awful and still has the same issue.

Thanks

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TLV1805-Q1: Delay over temperature

September 24, 2018, 6:14 am
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Part Number:TLV1805-Q1

Hello,

Where can I find Information of the change in propagation delay over temperature of the TLV1805-Q1?

BR,
Stefan

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TLE2082: alternative solutions

September 24, 2018, 6:54 am
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Part Number:TLE2082

Hello team,

my customer has been using so fa the TLE2082 but is requiring a replacement for it.

Specifically they need:

- package SO8

- Power supply ±12V and is going to be used in an acquisition chain

- Used as a current to voltage converter where the I=few microA and the gain is roughly 20K

- Used as an inverting op-amp with gain=4.7

- Used as buffer and driver for a few other stages

Do you have any suggestion in a possible replacement? Which one do you think would be a good fit between the LM6172IM and the LM6152?

Do you have any other suggestion?

Thank you in advance for your help.

Best regards,

Adrian

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LM139A: datasheet discrepancy?

September 24, 2018, 8:22 am
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Part Number:LM139A

Team,

My customer has the following question on SLCS006T:

After a morning of confusion, we believe we have spotted a typo in the LM139A datasheet, revised June 2015. Page 10, section 8.3, says "The output NPN sinks current when the positive input voltage is higher than the negative input voltage and the offset voltage." Page 12, Section 9.2.2.1 says "If IN– is higher than IN and the offset voltage, the output is low and the output transistor is sinking current."

Can you please confirm that the second description is correct?

Regards,

Aaron

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UA741: uA741

September 24, 2018, 9:10 am
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Part Number:UA741

Ronald,

For the attached circuit files, using TINA, is there a way to run simulation for Positive DC Pulse Signal as input source?

(Please visit the site to view this file)

Regards,

Neguse G.

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INA240: FIT data for INA240A2QPWRQ1

September 24, 2018, 3:03 pm
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Part Number:INA240

I work for an Automotive company and we use this current sense amplifier INA240A2QPWRQ1 . Would someone be able to provide Failure rate analysis(FIT) data for this part?

Regards,

Saikumar

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RTOS/XTR108: how to program it

September 24, 2018, 9:15 pm
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Part Number:XTR108

Tool/software: TI-RTOS

hello good night, I would like you to help me by providing a basis for how to program this xtr108 q I find it very interesting for your communication spi, (like some ADS11118Q1 that I acquired some time ago), I want to use it for an industrial project for my university for a PT100 from 0 to 300 °, please if you could provide me with a reference code I would be very grateful
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LMH6702: Noise model for LMH6702

September 24, 2018, 8:20 pm
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Part Number:LMH6702

请问官网上有这个器件的ADS仿真模型吗？

现在测试出来经过改模块以后的相噪恶化1dBm，能做到相噪不恶化吗？

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OPA548: size MPN OPA548F/500 and OPA548FKTWT

September 24, 2018, 10:09 pm
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Part Number:OPA548

Hello.

As I know MPN OPA548F/500 and OPA548FKTWT just different quantity for tape reel, but can anyone advise about the size for both MPN? Is it same size? What about the difference value labelled A0,B0 and K0?

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LF412: datasheet don't have the curve to verify if the model is proper in simulation

September 24, 2018, 11:38 pm
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Part Number:LF412

Hi, 

My customer wondering if there are testing curve for this part. Because now they are trying to compare the result of simulation(Pspice and TINA) and the datasheet, but there is no plot in the datasheet. 

May I ask that if there are any testing data is able to give to my customer for reference? 

Thank you.

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Need the datasheet of BFT70 part number

September 25, 2018, 12:04 am
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Hello,

Does anyone have the datasheet of BFT70. Kindly share it with us.

Thanks,

Sathish Kumar

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photodiode trans impedance amplifier

September 25, 2018, 12:21 am
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Hello everyone,

                   Am working with distance enhancement in Visible light communication.Am using OSD-100E photodiode.Am designing a trans impedance amplifier.This photodiode has a junction capacitance of 2500pf and an active area of 100mm2.Please recommend an IC that best suits for photodiode transimpedance amplifier design

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LMV116: Typical characteristics of Gain Phase vs Frequency

September 25, 2018, 12:51 am
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Part Number:LMV116

Hello,

Our customer use the LMV116, have a question.

In the typical characteristics of Gain and Phase vs Frequency Fig3.

Is the Gain axis correct?

It shows the frequency of BW is around 4MHz.

Best Regards,

Naoki Aoyama

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