LMV342: LMV342

Anuraj nk

Part Number: LMV342
Other Parts Discussed in Thread: LMC6482, LMC6492

Hi,

I am designing a precision rectifier circuit for one of my design. Here the input is from current sense transformer and this using differential amplifier it will be converted to single ended.

I am using an precision rectifier to convert that AC to dc. Please find the attached circuit. The part used is LMV342IDGKR. I have see that " Input voltage (either input) –0.3 5.5 V " in the datasheet. Can you tell me the attached circuit will work without any issue.(Simulation is working fine)

If not can you suggest a part which suits for rectifier application with the package of "2 Circuit Rail-to-Rail 8-VSSOP"

Regards

Anuraj NK

over 6 years ago

0 kai klaas69 over 6 years ago

Guru 140200 points

Hi Anuraj,

the LMV342 is not specified to work that way. The guaranteed common mode input voltage range is 0...4V. See section 6.6 of datasheet. What you plan is to apply an input voltage which heavily exceeds the specified common mode input voltage range. I wouldn't do that. This can result in phase reversal and saturation effects with large recovery times. More, you risk to destroy the LMV342!

Kai

0 Anuraj nk over 6 years ago in reply to kai klaas69

Intellectual 330 points

I got it. can you suggest a family/part which can be used for my application.or let me now how to select the part for rectifier application

0 kai klaas69 over 6 years ago in reply to Anuraj nk

Guru 140200 points

Hi Anuraj,

what is your exact input signal (common mode voltage, signal amplitude, frequency, waveform)?

Kai

0 Anuraj nk over 6 years ago in reply to kai klaas69

Intellectual 330 points

Supply volatge : 6V
Amplitude : 5V Max
Frquecny : 400Hz
Waveform : Sine

0 Ron Michallick over 6 years ago in reply to Anuraj nk

TI__Guru**** 157056 points

Anuraj,

The 6V supply greatly reduces the number of available op amps. After looking for rail to rail output and input with mention of phase reversal protection in data sheet lead me to LMC6482. See section 7.3.2
Consider increasing resistors (less load) to get closer to output rails. Adding capacitor across R30 is good for stability and bandwidth limiting (and noise reduction). Caps across op amp inputs hurts stability.

0 Anuraj nk over 6 years ago in reply to Ron Michallick

Intellectual 330 points

Hi,

The part LMC6482 meets my design requirement. But the maximum operating temperature is 85Deg. I am looking for a part for -40 to 125 Deg. Can you suggest a part which meet this.

Regards

Anuraj NK

0 Paul Grohe over 6 years ago in reply to Anuraj nk

TI__Guru 55056 points

Hello Anuraj,

The LMC6492 is the extended temperature range (-40 t o125) of the LMC6482. Basically the same device, but the limits are slightly wider due to the wider temp range.

0 Anuraj nk over 6 years ago in reply to Paul Grohe

Intellectual 330 points

Thanks

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LMV342: LMV342