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INA188: input bias current
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VFC32: Frequency Capabilities
Part Number:VFC32
I am looking into using the VFC32KP IC to convert a frequency to an analog voltage signal, and I was wondering if this chip will be capable of converting frequencies that range from 0-50 Hz. By looking at the data sheet, I will need a C1 value of 3.3uF and C2 value of 100uF along with a R1 value of 40K to make this chip read frequencies in this range.
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PGA281: Non-symmetric distortion performance
Part Number:PGA281
The distortion performance I'm seeing using this part looks very non-symmetric and varies quite a bit part to part. If I drive the inputs with a balanced signal I would expect the best performance, but instead the 2nd harmonic levels are as follows with a gain of 1 and a 5Vpp signal, no offset 10kHz sinewave input.
Balanced Input => 2nd harmonic at about -77dB, variation from 10 different parts is about -72dB to -85dB
Single-ended driving the positive input, negative input grounded => 2nd harmonic at about -72dB, variation from 10 different parts is about -70dB to -75dB
Single-ended driving the negative input, positive input grounded => 2nd harmonic at about -82dB, variation from 10 different parts is about -75dB to -90dB
So the performance seems to indicate that the part has the better performance if the input signals are mostly on the negative input. Is this consistent with the parts design?
I couldn't find any distortion metrics on the part at all in the datasheet. Is there any typical information available or an explanation for the widely varying performance from part to part?
Regards,
Jeff Lee
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LM231: conversion accuracy clarification
Part Number:LM231
Team,
My customer has the following question:
We are looking for insight on a parameter on the LM221, LM331 datasheet.
There is a parameter in the electrical characteristics that lists the conversion accuracy for the LM221 as 0.95 to 1.05 kHz/V
We're trying to piece together the overall accuracy of the device to see if we can avoid test selection of a motor speed loop. If we were running the device between 1Hz and 700Hz, would the design be affected by a gain error of +/-5%?
Regards,
Aaron
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OPA2335: Current Source circuit offset error
Part Number:OPA2335
Hi,
I would like to ask you a question about an offset error of "Current Source Circuit" which is shown at LOG104 datasheet page7, Figure8.
This question is related with my previous post as below.
https://e2e.ti.com/support/amplifiers/precision_amplifiers/f/14/t/571246
I have tried to do simulation of this circuit on TINA-TI.
And as a result, I have got an output offset error around 17uA at input current is 0A.
According to the datasheet (LOG104) Fig8, the input current range is from "10nA to 1mA" and output range is also the same as the input.
I think that the input range is limited from "17uA to 1mA" due to the offset vlaue is around 17uA.
So, could you tell me how to adjust the offset?
If I have any mistake or if you know better solution to get current source, please let me know.
Let me show my simulation circuit as below for your understanding easily.
Thank you for your support!
Best Regards,
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INA333: Customer Return failure for TEXAS INSTRUMENT INA333AIDGKTG4
Part Number:INA333
Hello Texas-Instruments,.
I am SQE from PLEXUS MANUFACTURING.
Recently, PLEXUS received customer complaint on a T-I part under P/N INA333AIDGKTG4. Amplifier passed functional testers @PLEXUS and HONEYWELL but failed at the end customer.
Preliminary analysis on the defect part revealed abnormal reading. Thus, we would appreciate if Texas-Instruments can approve this case and part return (RMA) for further investigation. We are seeing value of 2.1K Ohms @Pin4 and Pin 7. Date code = 2013 10 and PO# = 3624596
Thank you...
Andy YAP
Senior SQE (PLEXUS- HILLSIDE Penang MALAYSIA)
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LMP91000: LMP91000
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OPA376: Preamplifier for geohone, single supply 2.5v reference, 1.25v common mode
Part Number:OPA376
Hi,
I want to set up a geophone preamplifier with a 2.5v ref and 1.25c dc offset with 32 db gain.
I have a ti-tina schematic using the REF2025 to set the V+ to 2.5v and 1.25v common-mode output. But i am having trouble achieving the desired transient response.
I do not believe I need any filtering on the preamplfiier. I am using the OPA to drive an FDA (ths4551) with a 2nd order MFB low pass filter.
Is this the correct amplifier and Reference IC for my applicaiton?
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Survey High PSRR OP Amplifier for Current Sense
Hi Sir,
Could you help provide High PSRR better than OPA376 device? Application current sense.
Thanks.
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LMP91000: WSON14 schematic
Part Number:LMP91000
Does anyone have a dxf file for the WSON14 pad placement?
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INA188: Status of DRJ package
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XTR115: Failing the field
Part Number:XTR115
We are using XTR115 in one of our product to output 4-20 mA current.
Recently, we have had some products returned from the field where the current loop output has failed and current is permanently wrong.
Our investigation revealed the following:
Loop Voltage (VLoop) = 24VDC, RL = 250 Ohm, Iin = varied from 0uA - 250 uA, Measured current (I Loop)= 33.125 mA
The current stays the same regardless of the load resistor and Iin value but current do vary when the loop voltage is changed. i.e. 19.187 mA @ 10 VDC, 32 mA @ 15 VDC, 33 mA @ 30 VDC
We also measured resistance between Pin 3 and Pin 4 of the XTR115 and found that the measured resistance (R2) is only 15 ohm instead of the 25 ohm as specified in the module block diagram (below)
We believe due to the changes in R2 value, the XTR115 is not able to regulate the current on the loop?
What we cannot figure out is what has caused the change in R2 value?
What will happen (long term effect) if we short pin 3 and pin 4 of the XTR115?
Please see the circuit snippet below, our brief tests on in-house units have shown that when pin 3 and 4 are shorted together the current in the loop is then limited to 33 mA but when the short is removed the module recovers and starts to regulate the correct current on the loop. But failures from the field are not recovered and output incorrect current permanently.
Can you please look into this and advise what could cause permanent damage to R2 or is there anything else in the IC that is causing this behaviour, THANKS.
XTR115 failing in the field
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XTR111-2EVM: board dimensions
Part Number:XTR111-2EVM
Does anyone know the dimensions of the XTR111-2EVM Evaluation Module visible at the link below? Thanks much.
Best Regards,
Pete
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For use LMP91000EVM
Hi,
We plan to use LMP91000EVM for electrochemical measurement. From its user manual, the evaluation board can be connected to SPIO4 Board. I think we need to send I2C commands to the device and then receive the detection results. Does anyone use LMP91000EVM with SPIO4? What is the procedure to make them working properly? Thanks.
Joseph
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OPA337: Doubt in application note "Signal conditioning for piezoelectric sensors"
Part Number:OPA337
On page no. 27 of application note "Signal conditioning for piezoelectric sensors" in first bullet point on left hand side of figure 6, I want to know how the value of 5.85 in the denominator have been calculated.
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OPA277UA/2K5 - OPA277UA/2K5E4
Hi,
What is the difference between OPA277UA/2K5 and OPA277UA/2K5E4 ? From the data sheet, I could not find any difference. Kindly advise.
I have referred the 'package option addendum' page.(Please visit the site to view this file)
Regards
Atul Bhakay
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XTR116: XTR116 - using external R1, R2
Part Number:XTR116
Hi!
I know it's odd, but will this circuit work as intended?
I = Ii*(1 + R1/R2)?
The external R2 (shown) will be 25.5 ohm. R1 (shown) will be between 1k and 10k ohm (tbd).
The internal R1 + R2 = 2.5k will be across the op-amp input terminals - is this a problem?
The internal Rlim of course will not be in effect (I may put an external current limiting resistor in series with the emitter).
Thanks!
Also, for some reason the forum changes to Precision Data Converters when XTR115 or XTR116 are selected.
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INA128: high voltage differential input (60V) conversion to single ended
Part Number:INA128
I would like to convert a 60 input voltage (differential) to a single ended one, with output voltage approx 5V. My power supply is 24 volts. Which opam can you recommend to withstand 60V. I can cascade several of them for instance one for each entry
Regards
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OPA1612: Characteristic degradation at 85C or higher
Part Number:OPA1612
Hi team,
My customer is interested in OPA1612 for their application but its operating temp range doesn't meets their requirement(it'll be considered around Max 105C). Although I read through OPA1612 datasheet, I didn't expected the behavior of this device from 85C to 125C well.
What's the side effects when using this device in 85C or higher temperature range(less than 125C)?
If some parameters would be degraded, could you tell me Which characteristics will be degraded?
Regards,
Takashi Onawa
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LMP7721: LMP7721 as voltage follower
Part Number:LMP7721
Hello,
I am using LMP7721 in three electrode potentiostat (homemade) as a voltage follower.
I have tested the same but getting negative voltage output.
I have attached the circuit diagram for same.
How can I test the LMP7721, whether it is ok or not??
Which op-amp are best to use in potentiostat application???
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