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Original question:

LMP7704-SP: Instrumentation Amplifier-Suggest a suitable amplifier for the attached spec

LMP7704-SP: Instrumentation Amplifier

Sruthi Tobji
Prodigy 20 points

Part Number: LMP7704-SP

Tool/software:

Hi ,

For the above part number , its matching my specification but there are few that i have mentioned in the comments thats not there in datasheet , I would like to know about those.

Instrumentation Amplifier
Sl No Specification Value/Range TI COMMENTS
1 Total number of channels 04 or as per the design 04 or as per the design OK
2 Input impedance ≥ 50 MΩ, ≤ 5 nF NOT MENTIONED IN DATASHEET
3 Input Connection Differential input with floating common DIFFERENTIAL
4 Differential mode voltage range ±10mV to ±10V Voltage range : 2.7V to 12V
5 Common mode rejection ratio at gain 1000 90dB or better at DC to 50 Hz OK
6 Gain 1 to 1000 NOT MENTIONED IN DATASHEET
7 Accuracy +/- 0.02% high accuracy not mentioned value
8 Bandwidth DC to 10kHz 2.5MHz
9 Channel isolation Four port – Galvanic 600VDC NOT MENTIONED IN DATASHEET
10 Linearity +/- 0.01% High linearity, not mentioned value
  • 0
    TI__Guru* 77501 points

    Hi Sruthi, 

    I am commenting on NOT MENTIONED IN DATASHEET queries. 

    1. 

    LMP7704-SP is CMOS device with low Ib current, and the input impedance is > 1GΩ range. 

    2. 

    The LMP7704-SP's GBW is 2.5MHz. Based on gain bandwidth product, if the gain is 1000, the usable bandwidth is only 2.5MHz/1000 = 2.5kHz, So if your application is low, say near 250Hz range (assume 1/10th of the pole near 2.5kHz), it may be ok. Otherwise, this op amp may have bandwidth limitation or not applicable.  

    3. 

    The channel isolation between channel refers to the degree to which one channel is electrically isolated from the others, and it is specified in dB. This is a low voltage device and it is not designed for 600Vdc Galvanic isolation. 

    If the part has to comply with 600Vdc Galvanic isolation, it has to use isolated input stage, such as isolation op amp, transformer, capacitive isolation or opto. 

    https://www.ti.com/lit/sg/slyt532k/slyt532k.pdf?ts=1746800838041&ref_url=https%253A%252F%252Fwww.google.com%252F

    If you have other questions, please let me know. 

    Best,

    Raymond