TLV9062: TLV9062 simulation output noise

Allen Du

Part Number: TLV9062
Other Parts Discussed in Thread: LM7705

I am looking for an amplifer to amplify current transducers output singal, the supply of current transducers is 3.3V, analog output range is 1.65~2.95V, I hope to get a 3 times gain (0~3.9V output ).
I am trying to use TI spice to simulate, the current under test is a 100kHz PWM signal, I use Vpulse to simulate current transducer output.

1. Simulation shows amplifier output has overshoot. could you help have a look how to avoid this overshoot.

2. when input is 1.65V, i hope voutput is 0V, is it possible?

3. how to get exact 3 times gain.

4. If TLV9062 is not suitable , please advice another amplier, and 14bit ADC (at least 500kHz ~1MHz)

Thanks in advance!

OP-AMP.zip

over 4 years ago

0 Caro Gomez over 4 years ago

TI__Mastermind 24112 points

Hey Allen,

Welcome to e2e and thank you for archiving your project and attaching it!
I believe this can be best answered through the search by circuit function:

Filtered by 5V single supply and 1.3Vpkpk 100kHz input signal in a gain of 3.
Special notes to the design that Vcm must be set to 2.5V and the calculated Vout is from 0.55V to 4.45V (3.9Vpkpk).

Please see the parametric results for op amp recommendations: https://www.ti.com/amplifier-circuit/op-amps/general-purpose/products.html#p3270typ=-2.5;2&p3271typ=-0.5;2.5&p3295typ=-0.5499999999999998;0.2&p3294typ=0;0.5499999999999998&p22typ=1.2252211349000195;70&p23typ=0.3;2.18&p1261max=5;48&p1261min=0.9;5

As for the ADC recommendation, I would use the parametric search to narrow down the options: https://www.ti.com/data-converters/adc-circuit/products.html#

All the best,
Carolina

0 Allen Du over 4 years ago in reply to Caro Gomez

Prodigy 60 points

Hi Carolina,

Thanks so much, the page is very helpful.

I have another question, I calculated output gain by the resistors value, when input is high, there is no issue of output.

When input 0V, I am expecting output is also 0V, but actually output is 48.51mV, could you help advice how to fix this issue, how can I make output 0V when input is 0v.

Looking forward to seeing your reply!

+1 Gerasimos Madalvanos over 4 years ago in reply to Allen Du

TI__Mastermind 33723 points

Hey Allen,

Quick question. Could you show what voltage is being seen on the non-inverting input of the op amp? if you have 12mV on the non-inverting terminal and a gain of 4, you'll see the 48mV you have on the output. Additionally, it's worth noting the TLV9062 output swing from rail, which I have included below.

Please note that depending on load condition your output will not swing all the way to the negative rail.

Best,
Jerry

0 Allen Du over 4 years ago in reply to Gerasimos Madalvanos

Prodigy 60 points

Hi Jerry, Thanks a lot for your help.

+1 kai klaas69 over 4 years ago in reply to Allen Du

Guru 140200 points

Hi Allen,

using the LM7705 can help to allow the output of OPAmp to go all the way down to 0V.

Kai

+1 Ron Michallick over 4 years ago in reply to kai klaas69

TI__Guru**** 174306 points

Allen,

In the schematic, all the output (and input) loads terminate to ground. This will give an low output (with 0V input) as low as the greater of 2mV or 4*Vos + 3*VIN (Vos is the amplifier offset). [2mV is a guess at the no load ground shift inside the amplifier due to ground metal losses in op amp].

The model however might not give a no sinking current load VOL consideration. In a real circuit, try to make all the grounds points the same 0mV.

0 Allen Du over 4 years ago in reply to Ron Michallick

Prodigy 60 points

Thanks a lot!

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TLV9062: TLV9062 simulation output noise