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TLC555 functional block diagram
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OPA192 availability/equivalent type.
Hi
I’m designing a multiplexed DAQ, and I would like to follow TI’s recommendations for the amplifiers, but one that is recommended for multiplexed applications the OPA192, cannot be purchased anywhere.
Can you recommend other’s that will do that same job?
Cheers
m.b
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AMP01 instrumentation amplifier
Hi
What is the function of RC in the above circuit?
Thank you
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INA128 / supply voltage
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TLV3202AIDGK
For the
TLV3202AIDGK,What is the maximum Iq at the negative input at the following situations:
1:Vcc = 5V
Positive input = 2.5V
Negative input = 0.5V
2: Vcc = 5V
Positive input = 2.5V
Negative input = 4.5V
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XTR111 - Output current inaccurate and load dependant
Dear Sir,
I would like to use XTR111 to obtain 0 to 20mA/4 to 20mA current output for 0 to 5V input. Attached herewith is the schematic along with PMOS (CPH3351) and BJT(BC557b) datasheets for reference.
The problem is, when I connect different load resistances in the range of 10 ohm to 1.1K ohm for the same input voltage of 5V, the output current changes from 3.2mA for 10Ohm to 19.3mA for 1.1KOhm. For a load of 250 Ohms current is 17.6mA at 5V. When I remove R load and directly connect ammeter at the output I get 19.8mA at 5V.
I tried simulating the circuit on TINA but couldn’t find the PMOS part number. Can you guide me how to add a particular part in its library? While selecting the PMOS I took following parameters into consideration: Id=1.8A, Vdss=-60V, Vgss=+/-20V, Cinput=262pF. Do you think there is problem with PMOS or BJT part number selection(Attached datasheets)?
I have also tried the following experiments to troubleshoot :
1) I changed the transistor base resistance(R3) from 15 ohm to 2.2 Ohms; but there was no change in the result.
2) I changed the Rset resistor from 2.5KOhm to 2KOhm to check if this problem persists for other configuration i.e 0 to 25mA output for 0 to 5V input.
For 5V input, 250Ohm load, output current was 22.6mA.
For 5V input, No load(Only Ammeter), output current was 24.96mA.
Please guide me as to how I could resolve this problem.
Thank you,
Regards,
Komal Marathe
Niyantran systems
(Please visit the site to view this file)
(Please visit the site to view this file)
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Inquiry regarding "Test Circuits for Input Offset Voltage"
Hello, all
Now we are trying to have measurement on input offset voltage on each OpAMPs.
Then would like to know about the method of this measurement.
When referring 11-8 and 11-9 of "Chapter 11 Understanding Op Amp Parameters" (SLOA083), the correct method is to configure servo loop. Also, it mentions that "The action of the loop is to maintain the output of the DUT at zero volts.
However, when simulation this by TINA-TI, there could not be found the output voltage of DUT was zero volts. (We used OPA170 model for this reference.)
Please refer to the test result on this as below;
We would appreciate if you could show some detailed explanation on this measurement method.
We thank you in advance for your information.
Best regards,
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TLE2142 Power AMP Gap and Speed
Hi,
I use the 10-bit DAC DAC5652 to generate a trapezoid waveform,
the rising time and the falling time are 2us, the hold time is almost 2us.
The following is the waveform I measured from the input pin(PIN 2 +) of TLE2142.
Q1 But I found a gap at the rising edge, it is almost 1V in this case as following,
what is this? and how can I tackle this?
Q2 The slew-rate of TLE2142 + Buffer is extremely slow,
in the spec the min slew-rate of TLE2142 is 27-V/us and the buffer is 75V/us. How can I improve it.?
The following is the sch of power amp, but I only keep the buffer stage of the power amp.
The probe point of above figure is TP68, There is no load on the point.
The TLE2142 is powered by +36 and 0V
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PGA309 + TPS7A41 under electrically fast transient test
Hello
our pressure transmitter are mainly formed by your PGA309 programmable conditioner and power supply chip TPS7A41. in order to pass electrically fast transient test, we add some ferrite beads and TVS etc. see attached file below.
but the voltage output changes about from 1V to 2V even to 3V when the applied voltage reaches 3kV.after the test, the voltage output returns to 1V and no components are damaged.
our aim is 4kV,could you give me some advices?
best regards
Weiming
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OPA140 or OPA2140 Ib current.
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OPA140 OPA2140 use as a SQUARE WAVE OSCILLATOR (comparator mode)?
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Analysing 3rd order harmonic
My problem is to analyse the 3rd order harmonics which present in the HVAC line.
after that HVAC line(60Hz) ,MOV(Metal Oxide Varistor) will present to avoid the flow of high current to the components which is connected in the AC line.(eg.Surge Counter).MOV life span will be degraded day by day.Thus leakage current flows through the component. To analyse this we added voltage divider next to that and after reducing the voltage, we need to add filter circuit to pass 180HZ alone with minimum BandWidth. For that I followed Band Pass Filter with Sallen Key Topology.
I have attached the filter circuit with output using TINA software.
Can anyone tell me how to reduce the BW around 20Hz?
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How to estimate chopping noise for OPA188
I have a some questions about OPA188's chopping method.
1. Chopping method
One page 17 of the datasheet saids that internal offset corrections is done
at every 3us, the will be around 333KHz. Also the page 7 of the datasheet
indidates the presence of notch filter, but we can not any crevasse at
figure 8, open loop gain vs freq. Can we expect flat performance even if on
chopping frequency?
2. Chopping frequency
Is the chooping frequency is fixed or there is somehow frequency hopping in
order to reduce sharp noise?
3. Noise charcterization data.
Is there any charcterization data of en vs freq or Vo vs freq?
We know it should be used less than chopping freq, but in this time customer
wants to use up to 1MHz. We could like to know/estimate the affection of
noise at chopping frequency.
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xtr110 using with vp0808 mosfet
im want to convert from 0-10v to 4-20ma.... using the setting from here .... what i got is not i wanted...at 10v ...the current from drain is 15ma....i wanted 20ma precise|y..p|s advice 
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OPA349* NANO POWER AMP.
I need to know how the following devices OPA349 (nanowatt opamp), TLV3491/TLV3691(nanowatt comparators) behave when their DC power raises very slowly, 45 seconds or more from 0 to 3V...
I intend to use them in an application which operating from small solar panel which charge large capacitor by very small current.
All inputs are current limited to less than 100uA by serial resistors, so no latchup condition would appear on their inputs.
However, I wander how they will behave in very slow power up condition. Would they draw more current until supply reaches its minimum value? Would they just be non-operative until valid supply value been achieved? Is there risk of any internal latch-up conditions which would prevent them from operating?
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AMC1100 / GND connection of Figure 33
Hello,
The GND1 and the GND2 of AMC1100 is connected in the figure 33 on the page 15 in the datasheet.
Is this connection correct ?
Best Regards,
Ryuji Asaka
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Weird behavior in current monitor circuit
My application involves controlling fans to keep device temps within specs. I need to monitor high side current in this application, ie, the current powering the fans. Current span is 10mA to 500mA. Vout will feed directly ADC of CMOS uP.
I've been simulating this circuit below, as per snoa620, AN-32 Fet circuit applications, pg 12:
Previous inaccuracies made me switch op amp to OPA704 (which will be OPA705 in real circuit, but there is no model for 705).
Also used 2N3904 replacing JFET 2n3684, since I found no JFET model in TINA and no easy model for 2n3684 around. R1 and R3 have been set to resistor values that I already have. Relationship of 1/1000 was kept intact. R4 = 8k2 instead of 5k gives about 4.1V for Vout when Iload is 500mA, which is nice.
TINA circuit attached. (Please visit the site to view this file)
Power source for fans (VS2 above) is an LM317 with modified feedback network, so I can apply a wide input voltage range.
I have compiled a sweep list for different VS2 values and found:
| Vin | Iload | Vout | V/A |
| 12 | 0,591 | 4,891 | 8,274 |
| 10 | 0,493 | 4,080 | 8,282 |
| 8 | 0,394 | 3,268 | 8,293 |
| 6 | 0,296 | 2,456 | 8,309 |
| 4 | 0,197 | 3,930 | 19,944 |
| 2 | 0,099 | 0,828 | 8,407 |
For Vin (=VS2) = 4V and values around, circuit goes crazy. Vout is much higher than expected. It goes back to normal when Vin = 2V or lower.
Same thing happened for other sensitivities, ie, other values of R4, although at different values of Vin.
Why is this circuit behaving like this near Vin = 4V???
Side question1: why circuit overall sensitivity (V/A in above list) slightly increases when Iload decreases??
Side question2: is the only difference from this circuit shown to balanced circuit below the bias current compensation or is there any other reason for the 200ohm resistor at op amp V- below??
Thank you.
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photodiode transimpedance amplifier max current and bandwidth
Hello,
I would like to design a transimpedance amplifier for a photodiode and although I have been studying the theory behind it for a while now, I am still trying to understand some concepts.
The aim of the project is to measure the current of a photodiode similar to S2592-03 http://www.hamamatsu.com/resources/pdf/ssd/s2592-03_etc_kspd1003e.pdf
I have these questions :
1. Which value of the datasheet shows the maximum current of the photodiode?
2. Regarding the bandwidth of the amplifier:
The datasheet gives the rise time of the photodiode as 0.2usec.
Taken into consideration that:
The bandwidth of the photodiode, f3dB, and the 10 - 90% rise-time response, tr, are determined from the diode capacitance Cj, and the load resistance RL:
f3dB = 1/(2*pi*RL*Cj)
tr = 0.35/f3db - [ http://course.ee.ust.hk/elec509/notes/Lect12-photodiode%20detectors.pdf (page 36/80) ]
the bandwidth of the photodiode is caclulated as: f3dB = 0.35/0.2usec = 1.75MHz.
Should the bandwidth of the transimpedance amplifier be 1.75MHz as well? If not how much should it be and why?
Thank you.
Regards,
Theodora
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Something wrong in the ADS1158 datasheet
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Fully differential amplifier with single supply but differential input
Hi there,
I just tumbled over a bunch of application note, which where really helpfull but didn't really answered my question. Here it comes:
I have an audio codec which outputs a differential analog signal with an offset of 2.5V so that the signal is between 0.875V and 4.125V on both outputs. Now I'd like to use a differential amplifier as a line driver. By using standard OPAs I wouldn't need any negative voltage supply. How about differential amplifiers? Is there a way or is this a waste of time to think about? The application note "Differential Op Amp Single-Supply Design Techniques" explains how to use a FDA with only one supply but with a single ended input. I guess this doesn't work with a differential input?
Thanks for your help!
Regards,
Lennart
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