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  • TI Thinks Resolved

recommend Model

1. Less noise than OPA140.

2. Smaller than 1/f noise of OPA188 and lower power consumption.

3. Than OP90 / ° C (including 2.5 V, 2.5 mA) model of temperature drift, low power consumption

Need all support 12V input, rail to rail.

  • Hello Meng,

    Op amp voltage noise density (en) is roughly inversly related to the operating current. If you need lower noise than the OPA140, or OPA188, then you likely will need to accept higher operating current. There are bipolar input op amps with lower voltage noise density than the OPA140, but many will have higher operating current.

    1. Less noise than OPA140. - Is higher operating current than that of the OPA140 acceptable?

    2. Smaller than 1/f noise of OPA188 and lower power consumption. - The OPA188 is a chopper op amp design and does not have a 1/f region. The 1/f type noise is aliased to the chopping clock frequency region where it is attenuated by the internal sync filter. The OPA188 will still have low-frequency noise but it is simply the downward extension of the spectral noise density at low frequencies. That type of noise is superseded by 1/f noise in conventional, non-chopper op amps at low and very low frequencies. OPA188 datasheet Figure 17, Input Voltage Noise Spectral Density vs Frequency, is devoid of any 1/f noise.

    3. Than OP90 / ° C (including 2.5 V, 2.5 mA) model of temperature drift, low power consumption - Not sure what you are asking here. Please clarify.

    4. Need all support 12V input, rail to rail - is this common-mode, or differential voltage? What supply levels do you intend to use?

    Regards, Thomas

    Precision Amplifiers Applications Engineering

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