Noise Susceptibility Studies / Magnetic Field Tests - Status & Plans of the Aachen Group Tracker Upgrade Power WG Meeting June 4 th, 2009 Lutz Feld, Rüdiger Jussen, Waclaw Karpinski, Katja Klein, Jennifer Merz, Jan Sammet 1. Physikalisches Institut B, RWTH Aachen University

Outline Katja Klein2Status Report from Aachen Personal & funding Noise susceptibility studies Magnetic field test of DC-DC converters Plans Summary

Update on Personal Katja Klein3Status Report from Aachen Lutz Feld: team leader Waclaw Karpinski: electronics engineer –plus electronics workshop team Katja Klein: Helmholtz Alliance fellow (4-years from April 08) Two PhD students: – Jan Sammet – Rüdiger Jussen Diploma student: – Jennifer Merz (Effect of powering schemes on the material budget)

Funding News Katja Klein4Status Report from Aachen We have received from BMBF (= main German funding body for HE physics) for the next 3-year funding period, starting July 09:  invest money  3 PhD positions for SLHC

Summary of Activities Katja Klein5Status Report from Aachen Investigation of system aspects of novel powering schemes –PCB development & system tests  separate talk today by Jan Sammet Noise susceptibility measurements –Noise injection into silicon strip modules  covered in this talk Contribute to the development & characterization of magnetic field tolerant and radiation hard DC-DC buck converters, in coll. with CERN PH-ESE group –Magnetic field test  covered in this talk –Integration and test of CERN converters with CMS strip modules  only short summary of plans today Simulation of material budget of different powering schemes  final results ready, will be presented in the next meeting

Noise Susceptibility Studies Katja Klein6Status Report from Aachen Goal: identify particularly critical bandwidth(s) for converter switching frequency Bulk current injection (BCI) test-stand has been set up (Rüdiger Jussen) A noise current of 70dB  A (I eff = 3.16mA) is injected into the power lines  Differential Mode (DM) and Common Mode (CM) on 2.5V and 1.25V

BCI Set-up Katja Klein7Status Report from Aachen Noise is injected into a single module Frequency swept from 100kHz – 100MHz Step width: 0.1M Hz between 100kHz and 10MHz, 1.0MHz between 10MHz and 30MHz, 2.5MHz between 30MHz and 100MHz Injection & current probe Frequency generator Amplifier Spectrum analyzer Power supplies LISN Petal Current probe in CM configuration Noise injection into one module (6.4)

Effects on Module Noise Katja Klein8Status Report from Aachen

Effects on Module Noise Katja Klein9Status Report from Aachen Noise of strip 512 Mean noise of APV2 Edge strips much more sensitive due to their coupling to the bias ring On-chip common mode subtraction is very efficient for most strips More in back-up slides  Concentrate on edge strips

Peak Mode Katja Klein10Status Report from Aachen Peak at 6-8MHz, not at 1/(2  50ns) = 3.2MHz, as expected from shaping time Higher susceptibility for differential mode and 1.25V = pre-amp reference voltage Peak position independent of injected amplitude or module position

Peak vs. Deconvolution Mode Katja Klein11Status Report from Aachen Slight shift of peaks Interpretation difficult Deconvolution mode Peak mode

What about Higher Frequencies? Katja Klein12Status Report from Aachen Cable resonances can be observed if cable length L = n  /4 Two open ends (LISN 50 , module ~ 2  )  L = /2 Cable length varied between ~ 1.1m, 1.5m, 2.1m  f = 89.8MHz, 65.9MHz, 47.0MHz Measurements above ~ 30MHz are not reliable But no shift of peaks below 30MHz Zoom

Influence of Pre-amp Reference Voltage Katja Klein13Status Report from Aachen connected to Ground V125 V250 VSS=GND APV25 pre-amplifier [Mark Raymond] bias ring connect to V125 [Hybrid] strip Edge strips are capacitively coupled to bias ring Bias ring referenced to ground, pre-amp to 1.25V Bias ring connected to 1.25V instead of ground  Susceptibility decreases drastically  Pre-amp should be referenced to ground DM, 2.5V

BCI Summary Katja Klein14Status Report from Aachen Results are ~ consistent with measurements of Fernando Arteche (2004) Powerful method, but interpretation difficult (needs modelling) Shorter measurement time needed for faster turnaround (now ~ 1d per curve)  automation of measurement with LabView is foreseen (Rüdiger) Will be useful to characterize susceptibility of SLHC devices (hybrids, modules,...) F. Arteche, measurements with TEC petal in Aachen, 2004 (SLAC-PUB-11886, May 2006 )

Magnet Test Katja Klein15Status Report from Aachen DC-DC converters must function in ~ 4T magnetic field  no magnetic components Tests with 7T NMR-magnet at Forschungszentrum Jülich, close to Aachen Enpirion and CERN AMIS1 buck converters + LBNL charge pump tested (Rüdiger)  both versions with air-core and ferrite coils  13 DC-DC converters tested in total (can show only examples here)

Magnet Test Set-up Katja Klein16Status Report from Aachen Windows-PC running LabView PS Scope with probes Handle being inserted into magnet Magnet Handle for probes 9m long BNC cables B field Sourcemeter = Load

Efficiency Measurement Katja Klein17Status Report from Aachen Regulated by converter Value set in sourcemeter and monitored with current probe Set and measured with PS Measured with PS Correction for cable losses Note: the output voltage was not measured  this must be changed in the future! Efficiency was measured inside and outside of magnet with same set-up Measurement of other observables (ripple?) difficult due to long cables  what else should be measured?

Enpirion EQ5382D Buck Converter Katja Klein18Status Report from Aachen Enpirion with ferrite coil V out = 1.25V Enpirion with air-core toroid V out = 1.25V Eff. (7T) / Eff. (0T) Efficiency (7T) / Efficiency (0T) Severe efficiency loss with ferrite inductor Efficiency change < 0.5% with air-core inductor

AMIS1 Buck Converter w/ Air-Core Solenoid Katja Klein19Status Report from Aachen Efficiency (7T) / Efficiency (0T) Efficiency changes by less than 5% with air-core inductor Reason for larger deviations wrt Enpirion not clear, converter stability? With ferrite inductor, PS went in over-current condition (back-up slides)

LBNL Charge Pump Katja Klein20Status Report from Aachen No efficiency change for V out = 2.5V For V out = 1.25V, converter was probably not in same “state“ (stability problems)

Magnet Test Summary Katja Klein21Status Report from Aachen No surprises:  All converters with ferrite coils showed severe efficiency loss or over-current  All converters with air-core inductors, plus charge pumps, worked without significant efficiency loss We know now how to do the measurements and what to improve  Measure output voltage  Test various coil orientations Time needed for a measurement campaign: 2 days (but must be arranged) Suggest to repeat test with CERN ASIC in IHP technology and improved set-up  maybe also with AMIS2?

Future Plans Katja Klein22Status Report from Aachen System test with strip modules of  CERN buck converter PCB with discrete components (started)  CERN AMIS1 with Bristol PCB inductors (asap)  CERN AMIS2 buck converter ASIC (summer)  CERN IHP buck converter ASIC (autumn) PCB development for integration of DC-DC converters into tracker structures Automate and improve several existing test-stands (BCI, EMI, efficiency) Set up EMI-scanner to investigate coupling mechanisms of radiated noise Continue material budget studies Develop specifications for buck converter Get more practical experience with charge pumps

Summary & Conclusions Katja Klein23Status Report from Aachen A bulk current injection test-bench for noise susceptibility studies has been set-up and first measurements have been performed Various DC-DC converters have been tested in a 7T magnetic field Both set-ups need some improvements, but seem to be useful for tests of future converter and module prototypes Simulation of material budget for powering/cooling schemes finished, will be presented in the next meeting

Back-up Slides Katja Klein24Status Report from Aachen

The APV25 Katja Klein25Status Report from Aachen f = 1/(2  50nsec) = 3.2MHz

The APV25 Katja Klein26Status Report from Aachen 1.25V 2.5V * is connected to 2.5V since about 2000 *

The APV25 Katja Klein27Status Report from Aachen 1.25V 2.5V

On-Chip Common Mode Subtraction 128 APV inverter stages powered from 2.5V via common resistor (historical reasons)  mean common mode (CM) of all 128 channels is effectively subtracted on-chip Works fine for regular channels which see mean CM CM appears on open channels which see less CM than regular channels CM imperfectly subtracted for channels with increased noise, i.e. edge channels Katja Klein28Status Report from Aachen inverter V125 V250 VSS V250 R (external) v IN +v CM v CM v OUT = -v IN Node is common to all 128 inverters in chip pre-amplifier strip

Common Mode & Differential Mode Katja Klein29Status Report from Aachen Differential Mode (DM): Common Mode (CM): Load Source

AMIS1 Buck Converter w/ Ferrite Coil Katja Klein30Status Report from Aachen