Hi, I want to know how does this circuit work, because I have an application with a battery (12V/4Ah), with a charge controller, and I don't know if I can use this. I changed resistor RH and RL with 0.1 ohm - 1w.
Thanks for all your support.
Jenny
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Low and High-Side Battery Current Sensing with OPA241
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Please suggest a low cost reliable ECG circuit for my project
Hello TI,
I am trying to find out how low cost you can get and yet have a reliable, readable and interpretable ECG signal. I am looking for a cheap circuit (hopefully with INAMP and OPAMPS only ) but other designs with better signals and cheaper solutions are equally welcome.
Can the expert TI engineers suggest me some circuits. I do not need an adc in the circuit as I shall be directly feeding the output to a oscilloscope.
is there a new system for getting ecg's using the thumb and one common electrode. Can anyone send me such a circuit?
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OPA129 and LMC6001 offset voltage
Hi
I'm trying to amplify photo diode currents in the range of 0.1 to 50 nano amps. I used OPA129 and the suggested circuit in the datasheet and also LMC6001, although both have low input bias currents I get a huge offset voltage of about 200mV for a gain of 10M. Do you have any suggestion what I should do to reduce the offset?
Also my detection base line is not low enough, I mean by linearly changing the light detected by the photo diode I get first a flat signal which shows the offset and at some point it starts increasing, but I could see the change in the output current by just connecting the photo diode to an electro-meter and without the amplifier circuit. How can I somehow increase the sensitivity of the amplifier circuit?
Thanks
Roxana
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amplifier 1Hz - 10 MHz
Hi,
I am working on a project and i want an amplifier ranging from 1 Hz - 10 MHz and a power of 1W. I don't wont an op amp, either i need whole amplifier or an evaluation kit. Can you please suggest me some of them.
Thank you
Regards,
Prit Patel
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OP27A Trim/Null Pins - Noise Risks?
Many of the op-amps specify to leave the trimming (or NULL pins as they are called on the OP27A) floating if not used. Are there any concerns of noise on these pins affecting the offset?
Thanks!
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Symmetrical Topology?
Hi,
So, perhaps this is a novice question but, how come there aren't more Op Amp with symmetrical topology?
I know of some TO-78 ones and if I recall correctly, one in a DIP-8 case.
Wouldn't this topology be more accurate?
Adir.
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PGA309 Vout error
Recently, I use the PGA309 for my application. And I use the microcontroller to control the PGA309 through IIC .And I can read/write the PGA309 register successfully.But the Vout is still wrong. This makes me carzy!!! Here is my step:
1、Tied the TEST PIN to a microcontroller IO port, and before the registers' configuration I pull down the test pin.
2、 After the configuration set the test pin is high and enable the Vout.
The circuit diagram refer to the User‘s guide F3-5. The signal is 0.9125V but my Vout is just 25mV. I don't kown what is wrong with it.
so I ask for help here.
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what is the result will happen when I misconnect 7.5v power to output of opa333
Above is my circuit.
what is the result will happen when I misconnect 7.5v power to output of opa333
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ADS1292 for ECG application
It says on the data sheet and ECG and EEG applications Quick reference Guide that ADS1292 is a complete AFE for ECG applications and I was lead to believe that it is a better option than discrete components like INA333 and etc. After reading the topics in the forums i am a bit confused. I thought no external amplifiers, low-pass filter or high-pass filter would be required to achieve typical ECG signal with bandwidth of 0.05Hz to 100Hz.
Could anyone shed some light on this please?
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max short circuit current rating INA149
Hi,
What is the maximum output short circuit current rating for INA149? (Power supply +-3.3v)
Thanks,
Rajani
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ina333 with thermocouple input
I am using an INA333 with a 200 ohm gain resistor. I have 3V on V+ and Ground on V-. I also have Vref = ground (only have positive signals > 0V on +/- input of ina). I hook a thermocouple that when heated produces on the order of 6mV output. I am looking directly at the output pin 6. No other components. I see at the output a pulse type of train with period of about 110Hz. Can you explain why this is? I would expect that I see a steady state dc level! I would like to email a scope picture but am not sure how to do this until you respond.
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IVC102: does it take long to stabilize after saturation?
Hi, I am using an IVC102 with a photovoltaic sensor in the "reset-and-integrate" configuration depicted as Figure 1 of the IVC102 datasheet for a very low light measurement application (with an internal 10pF capacitor). It seems to work well under normal conditions. However, when the sensor is exposed to an ambient light, it takes about 10 minutes to stabilize and it seems to detect some kind of residue during that period of time. The sensor outputs 10uA and the voltage across its anode to cathode is 430mV when it's exposed to the ambient light (these numbers were measured with the sensor alone). The voltage is higher the IVC102's internal clamp on the pin 2 per its datasheet, but the pin 2 is tied to GND in this configuration. 20uA is much smaller than 200uA which can be applied to pin 2 (pin 3 can take more though). Both the S1 and S2 are closed during the ambient light exposure, expected to discharge any photo current/charge before each measurement. S1 and S2 are closed at the beginning of the measurement when the sensor sees virtually no light. The IVC102's output gradually goes down to "dark" in 10 minutes and it is really stable after that.
The sensor alone seems to respond much quicker than 10 minutes, say in a fraction of a second to become zero in voltage/current, though it's only measured in uA (not pico-amps).
Does anyone have any explanation to this phenomenon? I am asking a similar question to the sensor MFR from the sensor view point, but I wanted to know if there's anything I need to pay attention to for the IVC102 use?
Thank you,
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To reduce noise in INA105 difference amplifier circuit
we are using INA 105 in one of our instrumentaion applications. The range of signal we intend to use is from 0mV to 30 mV. We are using in differential mode with Unity gain. The problem we are facing is the noise obtained is around 150mV. We have used sufficient bypass capacitors across +/-15vdc supplies. Kindly provide a suitable method to limit the noise to near zero mV.
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OP07 vs. TLE2021A or OPA277 for EMI
Team,
My customer has used the OP07 and LT1097 in an application. He is worried about EMI around the 1-2GHz region. He would like to compare from a reference point he knows. We have recommended OPA188 and LMP2021 as other candidates to look at.
"I found the OP07 was once used in this design before the LT1097. Going back through the TI website, it looked like the OPA277 and TLE2021A are two matches that I think would both function in my application.
I reviewed the EMI datasheet and it showed about 19db EMIRR for the TLE2021A and 90DB+ for the OP277 at 1.8GHz, so I ordered some OP277's to try. It would be fascinating to know how the OP07 and LT1097 rate on that scale."
There doesn't look to be much info in the OP07 datasheet so I was hopeful one of the old timers on the forum may know.
Thanks,
Aaron
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OPA2171A1IDR input offset voltage higher than specs in datasheet
Can someone help to review below schematics to see any problem with the application of OPA2171A1IDR, customer claim high input offset voltage failure.
On top is the circuit design in the actual application.
It have all the resistor value as requested.
In actual application Pin8 (V-Ant) could be set to 3V or 5V depending on the user.
Depending on the amount of current drawn by the load Op-Amp A and B will change state accordingly.
We used it to detect Open, Short and normal operation of the load.
During the FA in the lab 5V is applied at Pin 8 (V-ANT).
Pin 2 is set at 1V
We adjust the voltage at pin 3 units the output change from low to high.
When this happen the voltage at pin 3 is much higher than 1.01V.
For a good unit it measure very close to 1V at about 1.001V.
For your info the input offset voltage is calculated by subtracting the voltage at pin 3 from the voltage at pin 2.
Therefore 1.01V – 1.00V = 0.01V.
Changing 0.01V to mV it give 10mV.
As stated in the specification the input offset is max +/-1.8mV.
Comparing 10mV to 1.8mV it show that the faulty units is out of spec.
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Common Mode Input Voltage for LMP2012QML-SP
Is it correct that the maximum input voltage at high temperature is between +2V and +3V (Vs = 5V)?
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what will be the total error in thermocouple measurement due ADC input Imedance.
Hello I am Designing Thermocouple temperature Display Using MSP430AFE233. MSP430AFE has 24 bit ADC. It also has on chip PGA which can be used to amplify signal. But one drawback of it is that it has low input impedance nearly 200K. Does 200 K input impedance is sufficient to avoid overloading of thermocouple . also I have 100 Ohm resistor in series with 24 bit ADC which is used to design the Antialiasing filter. Does 200 k input impedance is sufficient, or it will cause to change the input voltages. What is the power level of thermocouple signals, Does thermocouple can easily drive the 200 K load without Loading. And also I don't want use any opamp at input because it will cause following problem
1} I have to generate Negative rail power supply , Because Thermocouple signal within 55mV. This voltage is near the rail in single power supply.
2) I have to correct the offset error due to OPAMP in the circuit. (ADC offset can be easily compensated in software due to internal short terminal input channel measurement ) . But OPAMP offset error is hard to remove .
3) also adding another opamp increases cost. And My aim to achieve greater accuracy with low cost. ( that is why I chose MSP430 AFE).
Does any one can Solve my Problem? 200K input impedance is satisfactory for thermocouple measurement with the thermocouple sensitivity 40uV/c (K type). Does it will affect full scale accuracy And if yes then what will be total error in full scale?
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LM6132AIM
Good afternoon,
I`am having problems with the LM6132AIM amplifier.
we stress it from -40 to +80 celcius.
At -40 celcius our LM6132AIM is showing a malfoncioning.
is there any amplifier of similar characteristic that sould work at -40 or even less temperture?
thanks
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Long-term stability of the INA216
We are consideringtheINA216currentmeasurement applicationsofless than 1%.
Apart from theagingof theexternalresistor,Do you have anyinformation thattherehow muchagingofIC only?
There isinformationabout thelong-term stabilityofTI op ampof the pages below, but, is itmay be the same?
Any thoughts would be appreciated!
Regards, sopatopa
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EMIRR Testing
Is the same EMIRR(EMI rejection ratio) test that is done on the OPA188 performed on the OPA377 also?
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