CMOS AMP contains no BJT

 

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Good day, ladies and gentlemen,

I have a goal to find out COMS OPAMPS that has no BJTs in its. Unfortunately a lot of datasheets have no simplified schame of opamp in it. For example, AD80xx looks nice but i dont know where it contains bjts. ADA4666 looks great but has q1 and q2 bjt.

I would appreciate if somebody provided me a list of such AD OPAMPs.


Problem definition:

I am working in cryogenic laboratory, we are measuring superconductors and 2D materials in the very low temperatures. Signals we are interested in are at low amplitude and leading wires has high resistance( high resistance is needed to make wires low temperature conductance to get lower T in dewar). The best solution is to place pre-amp close to the sample--so opamp has to work in temperatures as low as 4K(about -275C). There are several articals in wich peoples uses comercial opamps for this purposes. The main feature: it must have no BJTs in it since bjts will have no charge careers in such a low temperatures. For example in that article authors tested HMC548 and HMC460(as i know Hittite is a part of AD now) :

http://ridl.cfd.rit.edu/products/cryogenic%20electronics/Badenhorst.pdf

everything is ok with them but current consumption(about 60ma) is a bit too high. So i am researching other variants that would suit our purpose.


Best regards, Usoltsev Alexey.

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  • 0
    •  Analog Employees 
    on Mar 5, 2015 4:59 PM

    Hi Alexey,

    Here are some of FULLY CMOS designed Amplifiers in ADI portfolio.

    1. AD8651/AD8652 (50 MHz, Precision, Low Distortion, Low Noise CMOS Amplifiers)

         a. 2.7 V to 5.5 V Supply Operation

         b. -0.1 V to (+Vs + 0.1 V) Input Voltage Range

         c. 30mV to (+Vs - 30 mV) Output Voltage Swing

         d. 350 μV max offset voltage, 4 μV/°C offset voltage drift and 1 pA typ Input Bias Current

         e. Gain Bandwidth Product of 50 MHz

         f.  5 nV/√Hz Voltage noise density and 4 fA/√Hz Current noise density

    2. AD8655/AD8656 (Low Noise, Precision CMOS Amplifier)

         a. 2.7 V to 5.5 V Supply Operation

         b. 0 to +Vs Input Voltage Range

         c. +Vs - 30 mV minimum Output Voltage Swing

         d. 250 μV max offset voltage, 0.4 μV/°C offset voltage drift and 1 pA typ Input Bias Current

         e. Gain Bandwidth Product of 27 MHz

         f. 4 nV/√Hz Voltage noise density

    Just take note that these devices are fully specified to work over the −40°C to +125°C temperature range.

    Regards,

    Jino

Reply
  • 0
    •  Analog Employees 
    on Mar 5, 2015 4:59 PM

    Hi Alexey,

    Here are some of FULLY CMOS designed Amplifiers in ADI portfolio.

    1. AD8651/AD8652 (50 MHz, Precision, Low Distortion, Low Noise CMOS Amplifiers)

         a. 2.7 V to 5.5 V Supply Operation

         b. -0.1 V to (+Vs + 0.1 V) Input Voltage Range

         c. 30mV to (+Vs - 30 mV) Output Voltage Swing

         d. 350 μV max offset voltage, 4 μV/°C offset voltage drift and 1 pA typ Input Bias Current

         e. Gain Bandwidth Product of 50 MHz

         f.  5 nV/√Hz Voltage noise density and 4 fA/√Hz Current noise density

    2. AD8655/AD8656 (Low Noise, Precision CMOS Amplifier)

         a. 2.7 V to 5.5 V Supply Operation

         b. 0 to +Vs Input Voltage Range

         c. +Vs - 30 mV minimum Output Voltage Swing

         d. 250 μV max offset voltage, 0.4 μV/°C offset voltage drift and 1 pA typ Input Bias Current

         e. Gain Bandwidth Product of 27 MHz

         f. 4 nV/√Hz Voltage noise density

    Just take note that these devices are fully specified to work over the −40°C to +125°C temperature range.

    Regards,

    Jino

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