2006.10.25.A. Matsuzawa, Tokyo Tech. 1 Nano-scale CMOS and Low Voltage Analog to Digital Converter...

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Transcript of 2006.10.25.A. Matsuzawa, Tokyo Tech. 1 Nano-scale CMOS and Low Voltage Analog to Digital Converter...

  • Nano-scale CMOS and Low Voltage Analog to Digital Converter Design ChallengesAkira Matsuzawa

    Tokyo Institute of Technology

    A. Matsuzawa, Tokyo Tech.

  • Contents1. Introduction Effect of technology scaling on analog performance --- Performance analysis of pipeline ADC --- Design challenges for ADC in nano-scale era --- No use of Operational amplifier -- - Comparator controlled current source - Successive approximation ADC - Sub-ranging ADC 4. Summary

    A. Matsuzawa, Tokyo Tech.

  • Performance and applicationsPipeline ADC is the major conversion architecture for communications and digital consumer products.

    A. Matsuzawa, Tokyo Tech.

  • Pipeline ADCTransfer characteristicsHoldSampleAmplify1st Stage2nd StageFolding I/O characteristics makes higher resolution along with pipeline stages.

    A. Matsuzawa, Tokyo Tech.

    -

    -

    +

    +

    Op amp

    -

    -

    +

    +

    Op amp

    DAC

    CMP

    CMP

    DAC

    Sample & Hold

    1st stage

    2nd stage

    Amplify (Hold)

    Sample

    Amplify

    Cf

    Cs

    Cf

    Cs

  • Speed and power1995-200610b12bConversion speed has saturated at 200 MHz Smaller mW/MHz is needed for low power operation.0.3mW/MHz for 10bit and 1mW/MHz for 12bit are the bottom lines.200MHz

    A. Matsuzawa, Tokyo Tech.

  • Effect of technology scaling on analog performanceTechnology scalingand performance of pipeline ADC

    A. Matsuzawa, Tokyo Tech.

  • Operating voltage trendOperating voltage(V)Design rule(nm)Design RuleAnalog HighAnalog LowDigital Low (Low leak)Digital HighITRS 2003ITRS 2001About 1V operationOperating voltage of scaled device will keep about 1V

    A. Matsuzawa, Tokyo Tech.

  • Operational amplifier for ADCVin+vout-vout+2VeffVs=Vdd-4Veff2VeffVin-VddOutput signal rangeGain Boost amp.Pipeline ADC needs high performance amplifier.The output signal range will be reduced along with voltage lowering.Vs=Vdd-0.7V

    Vs=0.5V @Vdd=1.2VVs=0.3V @Vdd=1.0V

    A. Matsuzawa, Tokyo Tech.

  • Requirements for operational amplifierSamplingAmplifyN:ADC resolutionMStage resolutionfor 1.5b pipeline ADCDC gainClosed loop gain-bandwidth Higher resolution requires higher open loop gain.Higher conversion frequency requires higher closed loop GBW.

    A. Matsuzawa, Tokyo Tech.

    Op amp

    -

    -

    +

    +

    Vn

    Cp

    Vout

    VDAC

    Cf

    Cs

    Op amp

    -

    -

    +

    +

    Cf

    Cs

    Vin

    Vn

    Vn

  • kT/C noiseLarger SNR requires larger capacitance and larger signal swing.Low signal swing increases required capacitance.CLvoutCapacitance (pF)n: configuration coefficient

    A. Matsuzawa, Tokyo Tech.

  • Effect of technology scalingGBW: 10GHzGBW: 2GHzConversion freq. : 1GHzConversion freq. : 200MHz90nm0.25umGain bandwidth of OpAmp increases along with technology scaling.However, can we increase every needed performances for ADCs?

    A. Matsuzawa, Tokyo Tech.

    &TSMC

    444400000225800000400000000211000000

    618900000315900000510000000309000000

    784600000401100000600000000388528000

    942500000484200000680000000450974000

    1098000000564600000764000000509546000

    1250000000646800000834000000547212000

    239400000012780000001226490000872738000

    3464000000188600000014351300001088590000

    4480000000246700000015687800001243450000

    5598910000302400000016617100001359890000

    6424900000387619000017444200001470170000

    7045070000455857000018043000001554270000

    7521380000517502000018496700001620520000

    7892830000571976000018852200001674060000

    8171520000616947000019138300001718230000

    8410810000654965000019373600001755280000

    8664170000691482000019570400001786810000

    8886940000723626000019737600001813970000

    9085380000752156000019881200001837610000

    9262980000777545000020006100001858360000

    9423080000799474000020115500001876740000

    9568250000817359000020212300001893120000

    9701130000833777000020298400001907810000

    9822500000848899000020375700001921060000

    9934720000862935000020445200001933080000

    10038000000875962000020508300001944020000

    90nm(CL=100fF)

    90nm(CL=200fF)

    0.25m(CL=100fF)

    0.25m(CL=200fF)

    Ids[A]

    GBW[Hz]

    IdsGBW

    100f

    100f

    GBW[deg]GBW/Ids

    3.75E-053.00E-044.46E+0984.851.49E+13

    5.00E-054.00E-045.60E+0982.941.40E+13

    6.25E-055.00E-046.42E+0980.761.28E+13

    7.50E-056.00E-047.05E+0977.911.17E+13

    8.75E-057.00E-047.52E+0975.421.07E+13

    1.00E-048.00E-047.89E+0973.229.87E+12

    1.13E-049.00E-048.17E+0971.239.08E+12

    1.25E-041.00E-038.41E+0969.498.41E+12

    1.38E-041.10E-038.66E+0968.077.88E+12

    1.50E-041.20E-038.89E+0966.837.41E+12

    1.63E-041.30E-039.09E+0965.756.99E+12

    1.75E-041.40E-039.26E+0964.806.62E+12

    1.88E-041.50E-039.42E+0963.976.28E+12

    2.00E-041.60E-039.57E+0963.245.98E+12

    2.13E-041.70E-039.70E+0962.595.71E+12

    2.25E-041.80E-039.82E+0962.035.46E+12

    2.38E-041.90E-039.93E+0961.525.23E+12

    2.50E-042.00E-031.00E+1061.085.02E+12

    2.63E-042.10E-031.01E+1060.684.83E+12

    2.75E-042.20E-031.02E+1060.324.65E+12

    2.88E-042.30E-031.03E+1060.004.48E+12

    3.00E-042.40E-031.04E+1059.714.33E+12

    3.13E-042.50E-031.05E+1059.454.18E+12

    3.25E-042.60E-031.05E+1059.214.05E+12

    3.38E-042.70E-031.06E+1059.003.92E+12

    3.50E-042.80E-031.06E+1058.803.80E+12

    3.63E-042.90E-031.07E+1058.623.69E+12

    3.75E-043.00E-031.08E+1058.453.59E+12

    3.88E-043.10E-031.08E+1058.303.49E+12

    4.00E-043.20E-031.09E+1058.163.39E+12

    4.13E-043.30E-031.09E+1058.043.30E+12

    4.25E-043.40E-031.09E+1057.923.22E+12

    4.38E-043.50E-031.10E+1057.803.14E+12

    4.50E-043.60E-031.10E+1057.703.06E+12

    4.63E-043.70E-031.10E+1057.602.98E+12

    4.75E-043.80E-031.11E+1057.502.91E+12

    4.88E-043.90E-031.11E+1057.422.85E+12

    5.00E-044.00E-031.11E+1057.342.78E+12

    200f

    200f

    GBW[deg]GBW/Ids

    3.75E-053.00E-042.32E+0987.61827.72E+12

    5.00E-054.00E-042.99E+0986.78257.48E+12

    6.25E-055.00E-043.88E+0985.90837.75E+12

    7.50E-056.00E-044.56E+0984.85477.60E+12

    8.75E-057.00E-045.18E+0983.82527.39E+12

    1.00E-048.00E-045.72E+0982.83227.15E+12

    1.13E-049.00E-046.17E+0981.86426.85E+12

    1.25E-041.00E-036.55E+0980.44626.55E+12

    1.38E-041.10E-036.91E+0978.99576.29E+12

    1.50E-041.20E-037.24E+0977.64656.03E+12

    1.63E-041.30E-037.52E+0976.38885.79E+12

    1.75E-041.40E-037.78E+0975.21365.55E+12

    1.88E-041.50E-037.99E+0974.11285.33E+12

    2.00E-041.60E-038.17E+0973.07585.11E+12

    2.13E-041.70E-038.34E+0972.09314.90E+12

    2.25E-041.80E-038.49E+0971.1664.72E+12

    2.38E-041.90E-038.63E+0970.25894.54E+12

    2.50E-042.00E-038.76E+0969.41414.38E+12

    2.63E-042.10E-038.88E+0968.63664.23E+12

    2.75E-042.20E-038.99E+0967.92054.09E+12

    2.88E-042.30E-039.10E+0967.26023.96E+12

    3.00E-042.40E-039.20E+0966.65043.83E+12

    3.13E-042.50E-039.30E+0966.08663.72E+12

    3.25E-042.60E-039.38E+0965.56453.61E+12

    3.38E-042.70E-039.47E+0965.08053.51E+12

    3.50E-042.80E-039.55E+0964.63093.41E+12

    3.63E-042.90E-039.62E+0964.21293.32E+12

    3.75E-043.00E-039.70E+0963.82353.23E+12

    3.88E-043.10E-039.76E+0963.46043.15E+12

    4.00E-043.20E-039.83E+0963.12133.07E+12

    4.13E-043.30E-039.89E+0962.8053.00E+12

    4.25E-043.40E-039.95E+0962.50932.93E+12

    4.38E-043.50E-031.00E+1062.23162.86E+12

    4.50E-043.60E-031.00E+1061.97062.79E+12

    4.63E-043.70E-031.01E+1061.72492.73E+12

    4.75E-043.80E-031.01E+1061.49332.67E+12

    4.88E-043.90E-031.02E+1061.27472.61E+12

    5.00E-044.00E-031.02E+1061.06822.55E+12

    Sheet3

    90nm(CL=100fF)[deg]GBW/Ids90nm(CL=200fF)[deg]GBW/Ids0.25m(CL=100fF)0.25m(CL=200fF)30u250.542M

    3.00E-054.44E+082.26E+084.00E+082.11E+0840u321.819M

    4.00E-056.19E+083.16E+085.10E+083.09E+0850u388.528M

    5.00E-057.85E+084.01E+086.00E+083.89E+0860u450.974M

    6.00E-059.43E+084.84E+086.80E+084.51E+0870u509.546M

    7.00E-051.10E+095.65E+087.64E+085.10E+08

    1.00E-058.00E-051.25E+096.47E+088.34E+085.47E+08

    2.00E-051.60E-042.39E+091.28E+091.23E+098.73E+08

    3.00E-052.40E-043.46E+091.89E+091.44E+091.09E+09

    4.00E-053.20E-044.48E+092.47E+091.57E+091.24E+09

    5.00E-054.00E-045.60E+0982.941.40E+133.02E+0986.78257.56E+121.66E+091.36E+09

    6.25E-055.00E-046.42E+0980.761.28E+133.88E+0985.90837.75E+121.74E+091.47E+0930u444.4M

    7.50E-056.00E-047.05E+0977.911.17E+134.56E+0984.85477.60E+121.80E+091.55E+0940u618.9M

    8.75E-057.00E-047.52E+0975.421.07E+135.18E+0983.82527.39E+121.85E+091.62E+0950u784.6M

    1.00E-048.00E-047.89E+0973.229.87E+125.72E+0982.83227.15E+121.89E+091.67E+0960u942.5M

    1.13E-049.00E-048.17E+0971.239.08E+126.17E+0981.86426.85E+121.91E+091.72E+0970u1.098G

    1.25E-041.00E-038.41E+0969.498.41E+126.55E+0980.44626.55E+121.94E+091.76E+0980u1.25G

    1.38E-041.10E-038.66E+0968.077.88E+126.91E+0978.99576.29E+121.96E+091.79E+09

    1.50E-041.20E-038.89E+0966.837.41E+127.24E+0977.64656.03E+121.97E+091.81E+09

    1.63E-041.30E-039.09E+0965.756.99E+127.52E+0976.38885.79E+121.99E+091.84E+09

    1.75E-041.40E-039.26E+0964.806.62E+127.78E+0975.21365.55E+122.00E+091.86E+09

    1.88E-041.50E-039.42E+0963.976.28E+127.99E+0974.11285.33E+122.01E+091.88E+09

    2.00E-041.60E-039.57E+0963.245.98E+128.17E+0973.07585.11E+122.02E+091.89E+09

    2.13E-041.70E-039.70E+0962.595.71E+128.34E+0972.09314.90E+122.03E+091.91E+09

    2.25E-041.80E-039.82E+0962.035.46E+128.49E+0971.1664.72E+122.04E+091.92E+09

    2.38E-041.90E-039.93E+0961.525.23E+128.63E+0970.25894.54E+122.04E+091.93E