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INA826 evm

July 24, 2014, 6:24 am
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Hello,

sorry for my English it is not my first language.

I am new to electronics.

I have a problem regarding INA826EVM.

I am trying to build a circuit on the INA826EVM board (see attachment for a schematic).

I am using Rigel 333 as an input of the instrumentation amp.( http://www.rigelmedical.com/downloads/rigel%20333%20instruction%20manual.pdf)

I set up the Rigel to Sine waveform with 1 Hz amplitude of 1 mV.

I am setting the gain close to 1000 with a 51 ohm resistor.

I am using R3 and C1 to create a low pass filter to cut at 100 Hz.

I am using Opa333 for the DC offset. The Rigel has an offset.

R1 and R2 are used because the Rigel is floating.

I am expecting to measure about a 1 volt to the output with a scope.

This will help me to calibrate the the circuit thus, I will be able to measure low level ecg signals accurately.

My problem is that in this situation the gain is about 592 and if I change the the frequency to 10 Hz the gain changes as well.

I have basic knowledge to electronics, haven't worked with much opamps and never with an instrumentation amplifier.

Thank you for the support,

Nikolay

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About how to use PGA309EVM soft ware

July 24, 2014, 1:30 am
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hi.can you help me to use PGA309EVM soft ware .i am not know how to use.i have read datasheet and user manul,but i confused still,so who can help me.

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ISO124U UL report & conditions of acceptability

July 25, 2014, 8:54 am
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Hi,

We are currently undergoing safety testing of our product and for that we need to provide the UL report and conditions of acceptability for the part.

I found this UL document:

http://www.ti.com/lit/ml/szzq072e/szzq072e.pdf

And this TI report:

http://www.ti.com/lit/ml/szzq095/szzq095.pdf

Even though they both reference file E181974 the TI report does not contain the ISO124U. Can someone help me obtain these documents ASAP?

Thanks,

James

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OPA211 start-up issue

July 25, 2014, 1:53 pm
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From field engineer David Chan:

Hi all,

The customer has run into a settling problem with the OPA221 for a microwave detector buffer application. ~30% of the parts that they have tested take 2-3sec to settle to the final voltage in a 10x non-inverting configuration under a 1MHz BW. They are looking to replace this device with a different part to make the design work. Attached is a partial schematic.

 Is there any particular reason why they would see only some of these devices encountering this problem?

(Please visit the site to view this file)

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AFE032 FCC Application schematic

March 14, 2014, 7:57 pm
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I intend to use AFE032 for FCC band PLC Modem system, on a 24V DC line. How similar will the schematic be, having the DC PLC Reference Design for AFE031 as the reference.

Will the line coupling circuits be the same?


Please mention other considerations which has to be accounted for.

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RE: Single Supply 4-20mA Receiver with RCV420

July 28, 2014, 5:12 am
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hello, I have done the following circuit. I had to lift the value because to out that remains at 1.26 V at the output of RCV420 . Placing a resistance of 20k and 4.7k in the OPA277 ,the output values ​​are achieved input 0 mA 8,07 V output and input 20mA 1.836V output .
Working perfectly.
But if I place an IC, DSP TMS320F28027 the output voltage is input 0 mA 7,64 V output and is not linial.
How can i do to to avoid this noise in the PCB?
I'm thinking isolate the circuit.
They can give me another option?

Best regards

John(Please visit the site to view this file)

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TLV3501 & OPA357 schematic review

July 28, 2014, 10:30 pm
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(Please visit the site to view this file)(Please visit the site to view this file)

Hi all,

These are the oscillation circuit(TLV3501 & OPA357) and the circuit for voltage detect.

 The oscillation circuit: 6.78MHz, 0.3V~3V Swing, Ref=1.65V

Comparator: AC voltage detect, using the function of 6mV hysteresis of comparator

I would like to know that the value of resistors is proper as well.

Could you review these schematic circuit?

Thank you.

 

Best regards,

Sammy Jeon.

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key factor of amp flicker noise

July 29, 2014, 10:49 am
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Hi all

Could you please tell me what is the key factor of amp's flicker noise (1/f noise)

I was testing noise performance of OPA335, and I found the flicker noise (1/f noise) is very small. Could you please explain why the 1/f noise of OPA335 is much lower than others.

I know it's an auto-zero amp, so its high frequency noise would fold back to low frequency, is 1/f noise also related to auto-zero topology?

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How to measure the noise density of OPA335

July 29, 2014, 10:53 am
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Hi all,

I'm calculating the noise performance of OPA335, and I found the noise density at datasheet is not smooth below 10khz, and there's no spec about it on datasheet. So if I want to calculate the noise with a 3dB frequency of 1khz, what noise density should I use?

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Can INA128P operate like single supply

July 28, 2014, 4:43 pm
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Hi, 

I'm trying to build an electrocardiogram, But I'm using a INA128P double supply, and all my system should be work in 0-5V single supply, so how can put in the "ground" of INA128P 2.5V,  (half 5V). can you help me with a schema i dont know much about electronic.

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Mux buffering options other than OPA192?

July 29, 2014, 1:40 pm
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I'm working on a data acquisition system that's selecting among 30 inputs (0 to 30V range) via muxes and digitizing them to an accuracy of about 100 uV.   Each input has an RC filter (10k / 0.1uF) before the mux, and then an op-amp buffer follows the mux.

The settling time between samples is adversely impacted by the comparatively fast slew rate of the output of the mux versus the slew rate of a 30V rated precision op amp - most op amps have input protection diodes that activate in this scenario, which drains the filter capacitor a bit during slewing requiring a long settling period to recover.

The new OPA192 is ideal for this application, but is brand new and has not yet been released in any of the smaller packages or as a dual/quad.  Are there other TI parts with similar capabilities?  Many datasheets do not mention maximum differential input voltages, or whether back to back protection diodes exist on the inputs, so finding other useful parts is difficult.

Thanks,

-Greg

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LT1013 failure mode

July 29, 2014, 6:13 am
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Hi Ti people,

I would like to know if there is a specific failure mode of the LT1013 precision amplifier when applying a voltage over the absolute maximum ratings defined in the datasheet of this component.

For example, if I use the LT1013 as a comparator, which will be the output state (+Vsat ?, -Vsat ?) when

- supply voltage Vcc+ exceeds 22V

- supply voltage Vcc- exceeds -22V

- differential input voltage exceeds +/-30V 

Thx,

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the circuit of pulse generation using TLV3501 and OPA357

July 29, 2014, 6:56 am
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Hi all,

Samsung inquired for the circuit of pulse generation using  TLV3501 and OPA357.

The circuit is as below.

 They did simulation using Tina file for triangle wave generator that you gave me at E2E before. However, they could find that the triangle wave is changed depending on the value of resistors. Even if the value of resistors was changed a little bit, the triangle wave was changed much.

 So the question is how much tolerance of resistors has an inpact on the period(or frequency) of total PWM pulses when the PWM pulses are generated through comparators after triangle wave occur.

That is, they would like to know the range of error due to the resistor.

The reason why they asked this question is that there is +/- allowable tolerance frequency at specific frequency range.

Also, when the capacitances are added at Vref, how much the capacitances have an influence on output voltage. (that is, parallel capacitor at Vref for both of TLV3501 and OPA357)

Would you give me the answers as soon as possible?

Thank you.

Warm regards,

Sammy Jeon.

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About overshoot of XTR300

July 30, 2014, 8:43 am
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(Please visit the site to view this file)

Now the IAIN-and IAIN + of XTR300 is shorted.
When we rise suddenly from 4mA to 20mA,it is happening overshoot.
(See the attached Fig1 & see the attached schematic)

Overshoot does not occur when it connect a resistance of 500Ω to IAIN-and IAIN +.
(Seethe attachedFig2)

Removed the L2 & L3 & L4 & L5 of the attached schematic, but the overshoot occurred.
Please tell me how to suppress the overshoot.

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how to import OPA227 PSPICE model?

April 26, 2012, 8:18 pm
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This model was published in 2002 and the files are different with other op amp models.

The zip file contains OPA227.MOD, OPA227.sch, and OPA227.slb

There is no .lib or .olb file.

how can I import them to the pspice library?

Thanks a lot!

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PGA309 Vout error

July 30, 2014, 2:12 pm
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Hello,

I am new to the PGA309 setup and am having problems with the output. I set up  the on board emulator to match the current bridge measurements for temperature and pressure. Ran the auto cal. sequence and then ran the simulator while reading Vout. I seem to get a good curve but it is not temperature compensated. For example at 10 deg. C at full load I get 3.9288V and at 200 deg. C at full load I get 4.5476 volts. My interpretation is that at a given load the voltage should stay the same for all temperature ranges.

Thanks,

Jim

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Inquiry regarding voltage output swing on OPA192

January 13, 2014, 11:59 pm
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Hello, all

Now we have one inquiry regarding voltage output swing (Vo) on OPA192 from our customer.

Please refer to the item below, and feedback us with your comment.

When referring page 3 of this datasheet, the positive rail of Vo is defined in case RLOAD=10kohm and RLOAD=2kohm individually.

However, they would like to know the case when RLOAD is more than 100kohm.

Please let us clarify how Vo value would be on this case.

We thank you in advance for your information.

Best regards,

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Inquiry regarding suggested minimum load impedance on XTR300

July 30, 2014, 11:32 pm
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Hello, all

Now we have one inquiry regarding suggested minimum load impedance on XTR300 from our customer.

Please refer to the item below, and feedback us with your comment.

Now we are using this device based on the configuration which is described on datasheet page 17 "Figure 39. Standard Circuit Configuration".

The voltage applied into power supply is V+=+15V and V-=-15V.

On above usage, we found overshoot if RLOAD=10ohm, however this was not found if RLOAD=30ohm.

Please let us clarify how to find the suggested minimum load impedance on this device.

We thank you in advance for your information.

Best regards, 

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TLC2254AIPWR Thermal Resistance information

July 31, 2014, 2:56 am
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Dears

Could you please let me know the θja,θjb and θjc of TLC2254AIPWR.

θja   Junction to ambient thermal resistance

θjb   Junction to board thermal resistance

θjc   Junction to case(bottom) thermal resistance

I need it to evaluate as soon as possible.

Thanks

Best Regards

Koji Hori

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ina321

July 30, 2014, 11:58 am
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The data sheet for the ina321 says that it turns on in microseconds from shutdown. Is there a spec for the turn on time or has it been measured?

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