チョッパかオートゼロか、それが問題 ??術記事 MS-2062 . Rev. 0 アナログ・デバイセズ社は、提供する情報が正確で信頼できるものであることを期していますが、その情報の利用に 関して、あるいは利用によって生じる第三者の特許やその他の権利の侵害に関して一切の責任を ...

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  • MS-2062

    .

    Rev. 0

    REVISION 2011 Analog Devices, Inc. All rights reserved.

    105-6891 1-16-1 0354028200

    532-0003 3-5-36 0663506868

    : Reza Moghimi

    (

  • MS-2062

    Rev. 0 2/6

    3 (ACFB) ADA4051 (CHOP1)(Gm1) (CHOP2) (Gm2)CHOP1 CHOP2 Gm1 1/f Gm3 CHOP2 CHOP3 DC 3

    40 kHz Gm4 Gm1 DC ()(SCNF)

    SC NF

    Gm1 Gm2

    Gm3Gm4

    CHOP1 CHOP2

    CHOP3

    Vnull

    Vos1

    Vos4 Vos3

    Vos2

    Auto correction feedback

    Auto correction feedback loop cancels the initial offset of Gm1s output; less ripple

    3.

    2

    4.

    http://www.analog.com/jp/ADA4051

  • MS-2062

    Rev. 0 3/6

    4 AD8628

    5

    f

    oiseSD

    Auto-zero

    Chopper Stabilized

    Chopper Stabilized + Autozero

    STD opamp

    5.

    Rs

    Rf

    6.

    http://www.analog.com/jp/AD8628

  • MS-2062

    Rev. 0 4/6

    AD8638 Residue Offset due to Chopping from Simulation

    0

    0.5

    1

    1.5

    2

    2.5

    0 1000 0 2000 0 3000 0 4000 0 5000 0 6000 0

    Rs (Ohm)

    Res

    idu

    e O

    ffse

    t(uV

    )

    Sim Rf/Rs=100

    7.

    AD8638

    ( 6 )

    7

    1. 2. 3.

    4. Rf Rs

    IB 5. ACFB ADA4051

    8

    (IMD) 9

    IMD fCHOP fIN fCHOP + fIN

    AD8628 AD8551 12 dB

    8.

    9.

    http://www.analog.com/jp/ADA4051http://www.analog.com/jp/AD8628http://www.analog.com/jp/AD8551

  • MS-2062

    Rev. 0 5/6

    10.

    IMD 1 AD8571 2 kHz 4 kHz 1 10

    CMOS

    AD8628

    30 s 40 ms

    1. VCM (10 V) 2. (40 nV/C

    ) 3. 1/f 4. CMRRPSRR 5. 6. ( 200C) 7.

    (

  • MS-2062

    Rev. 0 6/6

    1.

    Auto-Zero Chopper Stabilized Chopper Stabilized and Auto-Zero Very low offsetTCVOS Very low offsetTCVOS Very low offsetTCVOS Sample/hold Mod/demod Sample/hold plus mod/demod Higher low frequency noise due to aliasing Similar noise to flat band (no aliasing) Combined noise shaped over frequency Higher power consumption Lower power consumption Higher power consumption Wide bandwidth Narrow bandwidth Widest bandwidth Lowest ripple Higher ripple Lower ripple level than chopping Little energy at auto-zero frequency Lots of energy at chopping frequency Little energy at auto-zero frequency

    Analog Dialogue Vol.38 No.2: Bridge-Type Sensor Measurements Are Enhanced by Auto-Zeroed Instrumentation Amplifiers

    MT-055 Tutorial: Chopper Stabilized (Auto-Zero) Precision Op Amps

    Analog Dialogue Vol.34 No.1: 1

    Analog Dialogue Vol.32 No.2: 2

    http://www.analog.com/library/analogDialogue/cd/vol38n2.pdf#page=6http://www.analog.com/library/analogDialogue/cd/vol38n2.pdf#page=6http://www.analog.com/mt-055http://www.analog.com/jp/all-operational-amplifiers-op-amps/operational-amplifiers-op-amps/ad8572/products/cu_analog_dialogue_vol34_no1_jp/fca.htmlhttp://www.analog.com/jp/all-operational-amplifiers-op-amps/operational-amplifiers-op-amps/ad8572/products/cu_analog_dialogue_vol34_no1_jp/fca.htmlhttp://www.analog.com/jp/all-operational-amplifiers-op-amps/operational-amplifiers-op-amps/ad8572/products/cu_analog_dialogue_vol34_no2_jp/fca.htmlhttp://www.analog.com/jp/all-operational-amplifiers-op-amps/operational-amplifiers-op-amps/ad8572/products/cu_analog_dialogue_vol34_no2_jp/fca.html

    2

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