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CSA avec reset pour s- CMS , bruit en temporel ( Up-Grade TRACKER ) ( Asic R&D Version 1)

CSA avec reset pour s- CMS , bruit en temporel ( Up-Grade TRACKER ) ( Asic R&D Version 1). CSA Requirements. Qin = 1.2 fC to 10 fC (7.5 ke - , 62 ke -) Charge Collection Time = 10ns Cd = 5pF Power supply < 200 µW/amplifier F_slhc = 20 Mhz (version 1) or 40 Mhz

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CSA avec reset pour s- CMS , bruit en temporel ( Up-Grade TRACKER ) ( Asic R&D Version 1)

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  1. CSA avec reset pour s-CMS, bruit en temporel(Up-GradeTRACKER) (Asic R&D Version 1)

  2. CSA Requirements • Qin = 1.2 fC to 10 fC (7.5 ke- , 62 ke-) • ChargeCollectionTime = 10ns • Cd = 5pF • Power supply < 200 µW/amplifier • F_slhc = 20 Mhz (version 1) or 40 Mhz • Output pulse < 50ns • S/N = 20 (before irradiation) • ENC = 700 e- if Q = 15000 e- = 2.4 fC (before irradiation)Q is the most probable value for a Landau distribution of input charge • S/N = 10 (after irradiation) • ENC = 700 e- if Q = 7500 e- = 1.2 fC(after irradiation) • Front-End in AC coupling mode

  3. X10 115µA Idet 10µA Schematic - Power Supply • IBM 130nm Process • Power supply measurements @ 1.6V • NMOS input transistor : 143 µA (including bias current) • Bias current cascode : 28 µA • SF output : 200 µA • CSA Power Supply 171 µA (274 µW) compared to 253 µW in schematic simulation 10µA

  4. - + Noise in a Non Switched CSA Rf Cf Votage Noise Cd Current Noise Equation 2 Equation 1 • Rf is a noiseless resistor • G0w0 : GBW of amplifier

  5. - + Noise in Switched CSA • Using the weighting function(F S Goulding NIMA 1972 493-504) • Noise is measured just before the reset switch on Cf Votage Noise Cd Current Noise Equation 3 Equation 4 • Voltage noise is independent of switching time • Current noise is proportional to the switching time • If Strips are AC coupled Voltage noise is dominant whereas in DC coupled both (en and in) contribute to the output noise • G0w0 : GBW of amplifier loaded by Cd and Cf

  6. - + KTC noise Rf Cf Votage Noise Cd • Switched closed : at the end of Reset noise is stored in Cf or in Cd+Cf • Ideal amplifier (G=∞, w0=∞): no noise stored in Cd and v2=kT/Cf is transferred to the output during readout • Poor amplifier : noise is stored on both Cf and Cd and v2=kT/(Cf+cd) will be amplified during readout

  7. KTC noise Bandwidth amplifier > Bandwidth Ron*Cf (1/RonCf) Bandwidth amplifier < BandwidthRonCf Ron=100Ω, G0=57dB, f0=1GHz

  8. Noise calculation Noise simulation in AC mode and calculation for switched mode Noise simulation (AC noise) has been made for 2 different Rf in non switched CSA, in and en can be extracted Ouput noise is the sum of equation 1 and equation 2 Vout, noise2 = 760 nV2 @ RF1 100 MW Vout, noise2 = 615 nV2 @ RF2 1 MW (760 nV2, Vout=74 mV, Qin=10fC ~ ENC = 730e-) K1 = 73.8E9 K2 = 2.5E12 (Cf = 0.1pF) in2 = 5.85E-28 A2/Hz en2 = 8.3E-18 V2/Hz in= 24.2 fA/sqrtHz (eq 1.88 nA shot noise) en= 2.88 nV/sqrtHz ( eq 500 W resistor) Eq 1 and 2 Vout, noise2 (en)= 612 nV2 @ RF1 100 MW Vout, noise2 (in)= 146 nV2 @ RF2 100 MW en is dominant noise source

  9. Noise calculation • Noise calculation in switched mode using : • en(computed in previous slide) • in (computed in previous slide) • equation 3 and 4 Tr_noise simulation : 200 iterations Fmax = 5GHz Vout measured @ 26 ns Compute the standard deviation for all values picked @ 26ns Total output noise = 738 µV Vout = 74 mV ENC = 623 e- Vout, noise2 (en)= 610 nV2 Vout, noise2 (in)= 340 pV2 Total output noise =610 nV2 = 780 µV Vout = 74 mV ENC = 658 e- Calculation and TR_noise simulation in good agreement • 2 ways to simulate noise in switched CSA: • TR_noise • Standard AC noise + calculation • TR_noise: • No noise summary • More CPU time • More reliable • AC Noise: • Increase by 20% of noise • Noise summary available • Less CPU time

  10. 63.72 mV Voutvscd Input capacitor : Cd : 4.9 pF C(Cd + PCB + test socket) : 9 pF C(QFN package) : 0.5pF Cesd input pad : 2pF Total input capacitor : 12.5pF 63.72 mV @ 10fC Tin = 40ns Gconv = 6.3 mV/fC (In agreement with test 6.2 mV/fC))

  11. ENC vs Cd (AC noise simulation) ENC (5pF, 100 MW ) = 730e- ENC (15pF, 100 MW ) = 1260e- 5pF < Cd < 15 pF 1260e- Vout = 70mV Output Noise = 1.41mV 26ns Vout for ENC calculation 730e- Vout = 74mV Output Noise = 871µV

  12. Vout @ 25 ns for ENC calculation 1363e- 674e- ENC vs Cd (TR noise simulation) Cd = 5pF Cd = 15 pF Tin = 26 ns, simulation time 50ns, 100 iterations Vout = 55mV Output Noise = 1.2mV Vout = 71mV Output Noise = 766µV

  13. ENC vs Cd (TR noise simulation) Tin = 26 ns, simulation time 10µs, 200 pulses Cd = 5pF Cd = 15 pF Cd = 5pF Vout = 77 mV Stddev = 1.25 mV ENC = 1014 e- Cd = 12.5pF Vout = 64 mV Stddev = 1.59 mV ENC = 1552 e-

  14. ENC vs Cd (TR noise simulation) Cd = 12.5pF Vout = 67 mV Stddev = 1.62 mV ENC = 1511 e- Tin = 40 ns

  15. Tests Results - Noise Output Signal Dispersion • MIP : 1.2 fC • CSA RMS Noise = 1.32 mV • 1600 e- • CSA RMS Noise = 1.32 mV • 1600 e- • Fclk = 15 MHz • Asic 3 Reset CSA Output Qin = 1.2 fC Qin = 0 Cd ~ 12.5pF (5 pf in simulation) ENC for 5pf will be 1600/sqrt(2.5) = 1 011 e- 2 histograms lightly separated @ 15 MHz S/N = 7.5 (compared to 10 required)

  16. ENC ENC in e- @ 15 Mhz ENC (simulated AC) @ 12.5pF = 1140 e- ENC (simulated TR noise n pulses, Tin = 26ns, sim time 50ns) @ 12.5pF = 1080e- ENC (simulated TR noise , Tin = 26ns, sim time 10µs) @ 12.5pF = 1552e- ENC (simulated TR noise Tin =40ns) @ 12.5pF = 1511 e-

  17. Conclusion • CSA works well @ 15 Mhz • Step in progess: • increase performance (Speed, S/N, 40 MHz Clocking) • ASIC with few channels (CSA, Comparators) : possible submission fall 2012 • Both sensor polarities (holes or electrons) • CSA @ 1.2 v & low temperature

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