DC-DC Converters for CMS MPGD Testbeam G. Blanchot, F. Faccio, S. Michelis C. Fuentes, B. Allongue 19/05/2011G. Blanchot - CMS MPGD1

19/05/2011G. Blanchot - CMS MPGD2 –On-Time:SW1 is ON, SW2 is OFF, charging current from Vin into L. –Off-Time:SW1 is OFF, SW2 is ON, discharge of L current. –The triangular current in L is filtered by Cout to deliver a DC voltage. –Conversion ratios: Vin = 10V, Vout =2.5V, η = 80%, D = 0.25/0.8 = The Buck Converter Topology How it works

DC-DC Plug-in Modules SM01C 19/05/2011G. Blanchot - CMS MPGD3  SM01C is a DCDC based on the off-the-shelve LT3605 chip Delivers up to 5A at 2.5V (can be tuned) to be used for front-end development with DCDC converters. Same form factor as the rad tolerant AMIS2 DCDC module. SM01C SM01C efficiency: 75 – 85 % Low Noise: CM current < 0 dBuA above 7 MHz DM current < -10 dBuA above 7 MHz

DC-DC Plug-in Modules SM01C 19/05/2011G. Blanchot - CMS MPGD4  SM01C information available on DCDC project web site: VIN VOUT PGOOD ENABLE Pin NumberNet 1,3,4,5,6VIN 21,22,23,24,25,26,27, 28,29,30,31 VOUT 7,8,9,10,11,12,13,14, 15,16,17,18,19,20 GND 32PGOOD 2ENABLE VIEWED FROM TOP Pin assignment. Mechanical dimensions. Recommended footprint

SM01C#61 19/05/2011G. Blanchot - CMS MPGD5

SM01C#62 19/05/2011G. Blanchot - CMS MPGD6

Tests with Systems Transition board 19/05/2011G. Blanchot - CMS MPGD7 Full module for ATLAS SST, 2 Hybrids, 40 ABCn ASICs, 2 SM01C DCDCs wired to system using a transition board: DCDCs are 10 mm above of the sensors sitting on the protection cover. Using 35um Cu shield, no difference w.r.t. Linear PS. Noise susceptibility is very similar to the one observed with the UK modules. ColumnReference ENC ENC with SM01C + painted shield ENC with SM01C + Cu tape A B C D * No strobe delay calibration applied The module can be plugged on a transition board Samtec 2x16 to screw terminals interface.

Tests with Systems Customized voltages 19/05/2011G. Blanchot - CMS MPGD8 SM01C DCDC modules customized to deliver 3.3 and 5.3V for the CMS HCAL front-end. The converters are placed 25mm away of the front-end ASICs. Copper paint shield (no B field attenuation). The system noise is measured using different SiPM equivalent input capacitances. No difference w.r.t. equivalent measurement using the linear PS.

Testing at Testbeam 19/05/2011G. Blanchot - CMS MPGD9  Standalone tests  validate tolerance to B field up to 3T  Use dummy load and QC test stand at Prevessin.  System tests.  Upon validation, link DCDCs to front-end.  Compare performance using DCDCs and Lab PS.