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THS4001: Output voltage is 0.5V greater than the expected voltage with composite architecture.

August 12, 2019, 4:19 am
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Part Number: THS4001

Hi,

I am using the composite opamp with TLC2652 (chopper stabilized opamp) and THS4001 (High speed opamp).

If the input voltage is -5V from the battery V1 without the AC input, the expected output voltage is 2V since the gain of the circuit is 0.4.

I was able to measure the 2V if a decap of 6.8uF (polarized) is not added for THS4001 opamp power supply pins.

I am using a parallel combination of 0.1uF(ceramic) and 6.8uF (tantalum) at the power supply pins of THS4001.

With these two as decaps, my output voltage is 2.5V but with only 0.1uF decap, i am able to measure 2V.

What might be the reason for this condition.

Note: For TLC2652, only 0.1uF (ceramic) decaps are used.

Thanks

Pavithra Joshi

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OPA170-Q1: OPA170, OPA1678 BPF issue

August 12, 2019, 4:19 am
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Part Number: OPA170-Q1

Hi Sir,

The OPA1678.tsc works normally for 25KHz BPF, but the replacement of the OPA170 works abnormal. What is wrong?(Please visit the site to view this file)(Please visit the site to view this file)

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LMV321: Input CM spec

August 12, 2019, 4:21 am
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Part Number: LMV321

Hello team,

I'm a bit confused with the input CM spec for LMV321 at 2,7V supply. We show a typical of 1,9V and maximum of 1,7V. Shouldn't the 1,7V be the minimum spec?

Also what happens when the signal input on the non inverting pin exceeds the input CM range in a voltage follower configuration?

many thanks

Lutz

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LM239: What is the output when power voltage is lower than 2V

August 12, 2019, 8:07 am
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Part Number: LM239

Hi team,

   My customer is using this device as below,

  • Monitor the power level of 5V, and the power supply for LM239 is +/-12V;
  • The output is pulled up to 3.3V with 4.7k resistor;
  • One thing is that the 12V will power off first than 5V, and they can detect fault signal at the output; See waveform below.

They are curious about when the power voltage of LM239 is lower than 2V, such as 1V. Vp>Vn, what is the output voltage of LM239? Thanks. 

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LM139: Output state when one input up to Vcc

August 12, 2019, 8:15 am
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Part Number: LM139

If I’m holding one input at the midpoint by two identical resistors.  Like two 1k resistors so the reference level input is 3.3/2 = 1.65V and the other input will swing up and down 0v to 3.3v while Vcc=3.3V, can we guarantee across the temperature range that the output will also flip correctly accordingly?

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OPA857: Gain switching time?

August 12, 2019, 9:33 am
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Part Number: OPA857

I see that we can control the transimpedance gain by pulling CTRL pin logic high or low.

Can this be done, dynamically?

If so, what is the switching time?

Thanks.

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LMH5401: Resistor Selection Help

August 12, 2019, 1:42 pm
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Part Number: LMH5401

Team,

If the LMH5401 is driving a differential AC coupled high impedance load like the LMX2594, what do you have to consider in selecting a resistor between the  Out+ and Out-?  Do you have to match the impedance between the amp and the load (LMH5401)?

Thank you.

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TAS2562 FA

August 12, 2019, 3:05 pm
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DRV595: DRV595 higher power version or alternate TI parts to drive a TEC?

August 12, 2019, 6:54 pm
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Part Number: DRV595

I have been using the DRV595 to drive a TEC with success (4A, 12VDC) however I now need more current (up to 10A).  Is there a higher current version of this IC or alternatively is there a similar driver which I can interface with external mosfets?  Perhaps a monolithic high power H-Bridge IC? Like the DRV595 it would be ideal to drive the differential input single ended and run the driver at a minium of 400kHz in order to keep component size and electrical noise/ripple to a minimum for the TEC.

Any suggestions appreciated!

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LM124: EOL schedule

August 12, 2019, 7:45 pm
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Part Number: LM124

Hello,

I'd like to know the EOL information of the below products.

<Part Number>

LM124
SN54HC10
SN54HC00
54F244DM
54F373DM

Are they still producing now?

Please let me know the status and EOL plan of those parts.

If the part was obsolete, please provide the direct substitute information.

Thanks.

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OPA2333-HT: OPA2333-HT , lead length

August 13, 2019, 2:27 am
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Part Number: OPA2333-HT

Hi,

Need help to understand the following:

I have procured OPA233-HT with the order code OPA2333SHKJ. This comes in  Ceramic Dual Flat Pack (Package code HKJ ). My preferred packaging is SMALL OUTLINE INTEGRATED CIRCUIT (SOIC), which was not in stock at the time of procurement(OPA2333HD). The leads are too long for my application.

1) Can I reduce the length  of the leads by cutting it?

2) if yes, by much much?

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OPA132: Simulating the PSRR of the OPA132 with Tina

August 13, 2019, 2:54 am
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Part Number: OPA132

Hi engineers,

I have a problem about using Tina to simulate an OPA's DC PSRR.

I learned the PSRR of OPA in the Precision Lab. Below is the result of the Tina simulation in the Precision Lab tutorial.

I also chose OPA132 and simulated it with Tina. Here are the circuits and results I took.

As you can see, the power supply was changed (a total of 1V changes), and Vos did not change, which is different from the tutorial results in the Precision Lab.

In addition, use the same circuit, but the op amp is replaced by OPA111, Vos still has no change. As shown below.

However, still use this circuit, the op amp is replaced with OPA170, the power supply changes, the op amp Vos changes.

Below is the DATASHEET of the op amp OPA170. It can be seen that the change in Vos is consistent with that described in DATASHEET.

Therefore, it can be verified that the circuit taken should be no problem.

Why does the Tina simulation of the OPA132 in the Precision Lab get the correct results, and why does the Tina simulation I took not get the correct results?

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TLV6713: The .lib file has some syntax error

August 13, 2019, 4:33 am
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Part Number: TLV6713

Hi,

When I try to create a macro file using the TLV6713.lib in TI-TINA, I'm getting an error saying 'Missing Syntax Element - Line #43'.

Please could you verify the .lib file for any syntax errors?

Thanks for your help.

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THS7002: THS7002: Power Pad connection

August 13, 2019, 7:02 am
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Part Number: THS7002

Hi TI community,

sorry to bother you with a most probably stupid question ...

For my actual design I am planning to use the amplifier THS7002. But I get confused about the connection of the thermal pad. The PowerPad design considerations recommend the connection to the "internal ground plane".

Is this the same net as "GND-A" and "GND-B" or should the PowerPad have no connection to any pin?

Thanks in advance and best regards,

Gerald

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THS3217: Changing Resistor Values

August 13, 2019, 8:57 am
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Part Number: THS3217

Hello!

Will there be any problem or effect in the chip's performance if the following resistor values were changed to 100ohms?

Thank you!

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LMH6518: Question on clamping function

August 13, 2019, 1:14 pm
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Part Number: LMH6518

Hi team,

My customer is looking at using the LMH6518 but has a question. Our understanding on the over-voltage clamp is it gives you the ability to set a max/min output voltage level. They do not need this function, but want to know that clamping output signal will not damage the device.

Example, input is 1V, gain=10, power supply is 5V.

Thanks,
Mitchell

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THS3217: Filter to prevent oscillation

August 13, 2019, 1:16 pm
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Hi Team,

My customer has a question on the THS3217. To prevent oscillation (looking at figure 25 in section 7.11 on page 15), we can set the gain to about 5 or add a small filter to lower gain setting.

Do you have a recommendation of the type of filter for this current feedback amplifier?

Thanks,
Mitchell

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LMC6036: phase shift in bandpass filter

August 13, 2019, 6:53 pm
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Part Number: LMC6036

Dear,

customer designed one Passive Bandpass Filter as follow picture shows,bandwith: 1-50Mhz, and another piecture show the simulate result with this design, the real test result with PCBA is almost the same with the simulation, but still we have one problem:

there is different phase shift with different frequency with in bandpass bandwith,

for example, if no phase shift with 5MHZ, 

             then, will shift ahead with 1Mhz and shift behind with 20MHZ,

so, the output signal will distort if input frequency changed from 1MHZ to 20MHZ in this case,

customer need help to advise any solution to solve this problem,

the valid bandwith is 1MHZ-30MHZ in customer's design,

thanks.

b/r

vincent

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OPA699: OPA699

August 13, 2019, 9:13 pm
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Part Number: OPA699

Hello,

I have some question regarding the OA699 wideband high gain voltage limiting amplifier

1. Is it possible to give differential inputs to OPA699?

2. What is the propagation delay expected from worst case point of view?

3. What about the impedance matching? since i am working with differential input signal operating at 15MHZ?

4. Please let me know if an evaluation board can be purchased for the components?

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TL074: Vin condition and output confirm

August 13, 2019, 11:35 pm
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Part Number: TL074

Hi Team:

There are two question feedback from customer , please help ti , thanks a lot.

1.If only provide +12V and -12V disable (not provide voltage) , TL074_pin7 output will be 3.3V ? (fig as below)

2. If only provide +12V and -12V disable (not provide voltage) , RC726、RC727 open then Pin3 have 1.5V , TL074 like a  positive saturation of comparators and output Pin 1 will be +12V ? 

Regards / Mark

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