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AMC1100: Regarding better differential isolation amplifier than AMC1100

Caliber
Intellectual 810 points
Part Number: AMC1100
Other Parts Discussed in Thread: AMC1301, AMC1200, TLV170, OPA350, TLV6001, AMC1300, AMC1350, AMC1351

Dear TI team,

Good evening.

We are using AMC1100 for AC voltage sensing(0-270V),DC voltage sensing(300V DC and 600V DC) and AC current sensing(24A).

1.Can we use AMC1100 in AC voltage sensing and AC current sensing and is this good choice?

2.Can we use AMC1100 in DC voltage sensing(600VDC)?

In one of TI application note ,I found these lines while comparing AMC1100,AMC1200 and AMC1301,

"The AMC1100 or AMC1200 provide basic isolation with similar performance to the AMC1301 at a lower price point.For applications requiring   a bipolar output option,the TLV170 is an excellent choice."

Based on above we have few questions:

1.Can we replace AMC1100 for better performance with any of above differential isolated amplifiers?

2.As pin out are same,can we replace AMC1100 with AMC1301 or AMC1200?Any modifications required?

3.For single ended ADC,we are using OPA350 op amp ,but in application its said to use TLV170?is opa350 opamp ok?

or we need to use TLV6001 or TLV170?

Kindly check and clarify.

Thank you,

Caliber

  • 0
    TI__Guru**** 168605 points

    Hi Caliber,

    The AMC1100 is one of our first generation isolation amplifiers with 4250V-pk (basic) isolation.  The input range of this device is +/-250mV which makes it ideal for current shunt monitoring applications with shunts of micro to milliohm values.  You can certainly use this part for AC current sensing, but it may not be the best choice for AC and/or DC voltage monitoring.  Generally speaking, for AC or DC voltage monitoring applications, the 'shunt resistor' associated with the AMC1100 is the last resistor in the voltage divider circuit.  That resistor is generally hundreds to a few thousand ohms.  The low input impedance of the devices like the AMC1100 form a parallel combination with the shunt which leads to offset and gain errors.  For voltage measurements, the AMC1350 and AMC1351 offer a high impedance +/-5V input for AC or 0-5V input for DC voltage monitoring applications.  If BOM issues require you to limit the part count, I would look into the AMC1300 as an alternative to the AMC1100 or AMC1200.  The AMC1300 input structure allows you to compensate for gain errors in voltage monitoring applications by adding a second shunt in series with the VINn pin. 

    For the second series of questions, I believe the document you are referring to is SBAA229 which discusses the addition of a differential to single ended output stage after the isolation amplifier.  The choice of amplifier used in the differential to single ended output stage is yours, you are not limited to the devices mentioned in that Tech Note.

  • 0
    Guru 140200 points

    Hi Caliber,

    in the appnote the TLV170 is recommended for applications with a bipolar output, or by other words, in applications where the output voltage shall also go negative. In such an application an OPAmp with a wider supply voltage range might be necessary. The maximum supply voltage of TLV6001 and OPA350 is limited to 5.5V. So these OPAmps might not be a good choice for bipolar output when needing a higher supply voltage. The maximum supply voltage of TLV170, on the other hand, is 36V. This, in combination with the rather low price might be the reason why the TLV170 was suggested for bipolar output.

    In single ended applications your OPA350 can be used without problems, of course.

    Kai

  • 0 in reply to Tom Hendrick
    Intellectual 810 points

    Hi Tom,

    Thanks for explaining the difference, now we are updating our schematic for the second revision once updates are done we'll share the schematics with you for the verification

    We would like to have your mail ID to take the conversation to private

    With Regards

    Saravana

  • 0 in reply to Caliber
    TI__Guru**** 168605 points

    Great!  Looking forward to seeing the schematics.