Welcome
System Test Measurementswith Pixel Modules
and DC-DC Converters
Phase I Pixel Upgrade WorkshopGrindelwald, August 2012
Lutz Feld, Waclaw Karpinski, Katja Klein,
Jan Sammet, Michael Wlochal
Welcome Contents
29.08.2012 Jan Sammet - 2 -
• DC-DC Converters for the Phase I Pixel Upgrade
• Set-up for System Tests
• New Results from System Test Measurements
• A feature of previous measurements
• Tests with one pair of AMIS2/AMIS4 converters and one pixel module
• Tests with four pairs of AMIS4 converters and two pixel modules
• Front-end vs. back-end sensing
• Occupancy tests with low thresholds
• Thermal Cycling of DC-DC Converters – First Results
• Summary and Outlook
WelcomeAachen AMIS4 DC-DC Converters
29.08.2012 Jan Sammet - 3 -
AC_PIX_V8 A2.8cm x 1.6cm; ~ 2.0g
V8 E: 1mm smallest2.6cm x 1.5cm; 1.5-1.6g
V8 D: 1.5mm shorter2.65cm x 1.6cm, ~ 1.6g
V8 C: small caps2.8cm x 1.6cm; 1.6-1.7g
• 4 variants with AMIS4 produced
• Version A layout very similar to AMIS2_PIX_V7
• C, D, E: lower mass, smaller ( phase-2)
• ASIC: AMIS4 by CERN• Vout: 3.3V and 2.5V• fs = 1.5MHz• Toroidal plastic core inductor with L = 450nH• Pi-filters at in- and output
Welcome Implementation into CMS
29.08.2012 Jan Sammet - 4 -
• Installation onto supply tube• 24 to 26 DC-DC converters mounted on converter bus board• In total 32 converter bus boards
DC-DC converters Pixel detector
Bus board with 24 DC-DC converters (w/o shieldings)
WelcomeTests with 2 Modules and 8 Converters (AMIS2)
29.08.2012 Jan Sammet - 5 -
• System tests based on module qualification set-up
• Operated with up to two modules and 8 DC-DC converters
• Perform threshold scans and compare s-curve noise with and without DC-DC converters
HV (150V)
8 DC-DCconverterson common bus board
Long power cables (40m)CAEN Pixel PS
EASY4000
SY1527+ Branch
Controller
PSMA4603
Moduleadapter
Module
Connectorboard
V
A
V
D
V
D
V
D
V
D
V
A
V
A
V
A
Moduleadapter
Module
Connectorboard
Const. analogueload
readout
readout
Modules
DC-DC converters
Dynamic digital load
I (t)
0.17
0.35
Welcome Previous Measurements
29.08.2012 Jan Sammet - 6 -
Hardware configuration:• One pixel module• One pair of AMIS2_V7 / equivalent CAEN PS• Front-end sensing
Results:• Reproduction of previous results
Unintended feature of previous measurements:• Vana is set by measuring analogue current on TB; not in ROC
PreTest sets voltage of analogue regulator on ROC to maximum (Vana = 255) Larger current through preamplifier reduces sensitivity to intrinsic noise Small dropout of regulator increases sensitivity to external noise (e.g. orbit gaps) Measurement under unrealistic conditions
WelcomeNew Tests with AMIS2_V7 (S-Curve Noise)
29.08.2012 Jan Sammet - 7 -
Results:• Reproducibility of identical measurements: 0.5e-
• Average noise approximately 5e- (3.2%) higher than with Testboard• Almost no difference between CAEN and DC-DC converters• CAEN slightly more sensitive to orbit gaps (noise increased 1e- 0.6%)
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
Hardware configuration:• Single module• One pair of AMIS2_V7 vs. equivalent CAEN• Front-end sensing
WelcomeNew Tests with AMIS2_V7 (Threshold)
29.08.2012 Jan Sammet - 8 -
Results:• Reproducibility of identical measurements: 75e-
• No significant differences
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
Hardware configuration:• Single module• One pair of AMIS2_V7 vs. equivalent CAEN• Front-end sensing
WelcomeTests with AMIS4_V8A (S-Curve Noise)
29.08.2012 Jan Sammet - 9 -
Hardware configuration:• Single module• One pair of AMIS4_V8A / equivalent CAEN• Front-end sensing
Results:• Noise with AMIS4 slightly lower (1e- / 0.6%) than with AMIS2• With AMIS4 and (inv.) orbit gaps, no significant increase in noise• With CAEN and const. load no significant increase in noise• With CAEN and (inv.) orbit gaps, noise increases by ~ 1e- (0.6%)Software configuration:
• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
WelcomeTests with 8 x AMIS4 (S-Curve Noise)
29.08.2012 Jan Sammet - 10 -
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
Hardware configuration:• Four pairs of AMIS4_V8A / equivalent CAEN • Two modules powered by one converter pair• Plots are from M806• Front-end sensing
Results:• With CAEN PS and orbit gaps, noise increases by 36%• With CAEN PS and inv. orbit gaps, noise increases by 10%• No significant increase with constant load• No significant increase with DC-DC converters
WelcomeTests with 8 x AMIS4 (S-Curve Noise)
29.08.2012 Jan Sammet - 11 -
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
Hardware configuration:• Four pairs of AMIS4_V8A vs. equivalent CAEN • Two modules powered by one converter pair• Plots are from M1176• Front-end sensing
Results:• With CAEN PS and orbit gaps, noise increases by 19%• With CAEN PS and inv. orbit gaps, noise increases by 15%• No significant increase with constant load• No significant increase with DC-DC converters
Welcome VA and VD at the Module
29.08.2012 Jan Sammet - 12 -
-3V offset
DC/DCCAEN
Hardware configuration:• Four pairs of AMIS4_V8A / equivalent CAEN• Two modules on same converter pair
Observation:• DC-DC converters reduce oscillations• With DC-DC converters VA is hardly affected by load variations on VD
No add load 2A
Inv OGOrbit gaps
No add load 2A
Inv OGOrbit gaps
Oscilloscope settings:• VA: 100mV and 20µs per division• VD: 100mV and 20µs per division
-2V offset
-2V offset
-2.5V offset
-2.65V offset
-2V offset
-2V offset
-2.75V offset
-3V offset
-2V offset -2V offset
-2.8V offset
-2.8V offset
-2V offset -2V offset
-2.8V offset
WelcomeTests with 8 x AMIS4 (Threshold)
29.08.2012 Jan Sammet - 13 -
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
Hardware configuration:• Four pairs of AMIS4_V8A / equivalent CAEN • Two modules powered by one converter pair• Plots are from M806• Front-end sensing
Results:• No significant differences
WelcomeTests with Low Threshold / High Occupancy
29.08.2012 Jan Sammet - 14 -
Software configuration:• Trimmed to low threshold (10 Vcal DACs)
Inefficiencies
Results:• Highest noise with TB, lowest with AMIS4:
• CAEN to DCDC: +1.6e- = 0.6%• Testboard to DCDC: +5.7e- = 2.3%
• Lowest threshold with TB, highest with CAEN• CAEN to DCDC: + 3.7e- (0.3%)• Testboard to DCDC: - 32.9e-
(2.3%)• Number of dead/busy pixels similar in all cases
Hardware configuration:• Four pairs of AMIS4_V8A / equivalent CAEN • Two modules powered by one converter pair• Back-end sensing• Plots are from M806
with testboard with CAEN with DCDC
WelcomeFirst Results with Thermally Cycled Converters
29.08.2012 Jan Sammet - 15 -
• Eight converters cycled successfully• Load during cycling: 25 W• In ~10h: 3 x +20°C ... -40°C
10 x +20°C ... -20°C 2 x +20°C ... -10°C 50min @ 0°C
No defects, no problems, no effect on system tests System tests with converters @ 0°C show no abnormality
WelcomeSystem Tests after Thermal Cycling
29.08.2012 Jan Sammet - 16 -
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
Hardware configuration:• Four pairs of AMIS4_V8A• Two modules powered by one converter pair• Plots are from M806
Results:• No problems observed after thermal cycling
TDCDC = 0°CTDCDC = 20°C
WelcomeSystem Tests after Thermal Cycling
29.08.2012 Jan Sammet - 17 -
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
Hardware configuration:• Four pairs of AMIS4_V8A• Two modules powered by one converter pair• Plots are from M1176
Results:• No problems observed after thermal cycling
TDCDC = 0°CTDCDC = 20°C
Welcome Summary and Outlook
29.08.2012 Jan Sammet - 18 -
Summary
• New measurements performed with more reasonable configuration
• In all tests AMIS4 DC-DC converters did not cause any additional noise or performance degeneration
• AMIS4 converters reduce the impact of fast load variations
• We did not encounter any problems operating AMIS4 converters with front-end or back-end sensing of the CAEN PS
• After thermal cycling eight converters, none has shown any abnormality
Outlook
• Perform measurements with full bus board
• Improve monitoring features of cycling software
Welcome
Back-Up Slides
29.08.2012 Jan Sammet - 19 -
Welcome Aachen DC-DC Converter
29.08.2012 Jan Sammet - 20 -
ASIC: AMIS2 by CERNIout < 3AVin < 12VVout configurable; 2.5V & 3.3Vfs configurable, e.g. 1.3MHz
PCB:2 copper layers a 35µm0.3mm thickLarge ground area on bottom for cooling
Toroidal inductor:L = 450nHRDC = 40m
Shield/heat sinkA = 28 x 16 mm2
M 2.5g3.8% of a radiation length
“PIX_V7“:
Design guidelines from CERN grouphave been implemented.
Pi-filters at in- and output
Welcome AMIS4 ASIC
29.08.2012 Jan Sammet - 21 -
Features:• Bandgap and 4 linear regulators integrated• Dead time handling with adaptive logic• Triplication and logic against SEU• Improved power transistor design wrt TID• Over-current protection• Over-temperature protection• Input under-voltage protection• State machine for soft start-up procedure, handling of protection signals and generation of “power good“ signal
Operating parameters:• Vin < 10V• Iout < 3A (4A @ -30°C)• fs = 1-3MHz• L = 200-500nH
Received chips:• 20 bare chips, bonded and packaged in Aachen• 40 chips, packaged by Europractice
WelcomeReproducibility of Measurements
29.08.2012 Jan Sammet - 22 -
N(T) = T (0.36 ± 0,02) [e-] ± 1°C ± 0.36e-
• Standard deviation of individual measurements: ~21e-
• Standard error of the means of individual measurements : ~0.08e-
• Standard deviation of the mean of four identical measurements: 0.38e-
• Fluctuation due to temperature changes (of the coolant): 0.36e-/°C Guestimate: expected fluctuations < 0.38e- 0.36e- 0.5e-
[e]
[°C]
Welcome CAEN vs. 2 x AMIS2_V7
29.08.2012 Jan Sammet - 23 -
Hardware configuration:• Single module• One pair of AMIS2_V7 vs. equivalent CAEN• Back-end sensing
Results:• With CAEN PS and orbit gaps, noise increases by 23% (75)• With CAEN PS and inv. orbit gaps, noise increases by ~3• No significant increase with constant load• No significant increase with DC-DC converters
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
Welcome CAEN vs. AMIS4_V8A
29.08.2012 Jan Sammet - 24 -
Hardware configuration:• Single module• One pair of AMIS4_V8A vs. equivalent CAEN• Back-end sensing
Results:• With CAEN PS and orbit gaps, noise increases by 23% (75)• With CAEN PS and inv. orbit gaps, noise increases by ~3• No significant increase with constant load• No significant increase with DC-DC converters
Same results as with AMIS2_V7Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
WelcomeTests with 8 x AMIS4 (S-Curve Noise)
29.08.2012 Jan Sammet - 25 -
Hardware configuration:• Four pairs of AMIS4_V8A / equivalent CAEN • Two modules powered by two converter pairs• Front-end sensing• Plots are from M806
Results:• With CAEN PS and orbit gaps, noise increases by 36%• With CAEN PS and inv. orbit gaps, noise increases by 10%• No significant increase with constant load• No significant increase with DC-DC converters
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
WelcomeTests with 8 x AMIS4 (S-Curve Noise)
29.08.2012 Jan Sammet - 26 -
Hardware configuration:• Four pair of AMIS4_V8A vs. equivalent CAEN• Two modules powered by two converter pairs• Plots are from M1176• Front-end sensing
Results:• With CAEN PS and orbit gaps, noise increases by 19%• With CAEN PS and inv. orbit gaps, noise increases by 15%• No significant increase with constant load• No significant increase with DC-DC converters
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
WelcomeCAEN vs. 8 x AMIS4_V8A (M806)
29.08.2012 Jan Sammet - 27 -
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
Hardware configuration:• Four pairs of AMIS4_V8A vs. equivalent CAEN • Two modules powered by two converter pairs• Plots are from M806• Back-end sensing• CAEN measurements with front-end sensing (back-end sensing with CAEN only and large load variations is not feasible)
Results:• No significant increase with constant load• No significant increase with DC-DC converters
WelcomeCAEN vs. 8 x AMIS4_V8A (M1176)
29.08.2012 Jan Sammet - 28 -
Software configuration:• Trimmed threshold = 60 Vcal DACs• Use Vana and all other parameters from configuration with testboard
Hardware configuration:• Four pairs of AMIS4_V8A vs. equivalent CAEN • Two modules powered by two converter pairs• Plots are from M1176• Back-end sensing• CAEN measurements with front-end sensing (back-end sensing with CAEN only and large load variations is not feasible)
Results:• No significant increase with constant load• No significant increase with DC-DC converters
Welcome2 x AMIS4 vs. CAEN, Front-End Sensing
29.08.2012 Jan Sammet - 29 -
DC/DCCAEN
Hardware configuration:• Single module• One pair of AMIS4_V8A vs. equivalent CAEN• Front-end sensing
System tests: small increase (<1% / ~2) in noise with CAEN and (inv.) orbit gaps
Observation:• Larger oscillations with CAEN• In particular also on VA
-3V-3V
-3V-3V
-2.8V
-2.8V
-2.8V
-2.8V
Welcome2 x AMIS4 vs. CAEN, Back-End Sensing
29.08.2012 Jan Sammet - 30 -
DC/DCCAEN
Hardware configuration:• Single module• One pair of AMIS4_V8A vs. equivalent CAEN• Back-end sensing
System tests: smallish increase (~1% / ~3 ) in noise with CAEN and inv. orbit gaps significant increase (23% / ~75 ) in noise with CAEN and orbit gaps
Observation:• Larger oscillations with CAEN• With CAEN PS, oscillations on VA larger than with front-end sensing• However: small difference between iOG & OG
-3V
-2.8V
-3V-3V
-3V
-3V
-3V
-3V
Welcome2 x CAEN , Front-End Sensing
29.08.2012 Jan Sammet - 31 -
No add load 2A
Inv OGOrbit gaps
Welcome2 x CAEN, Back-End Sensing
29.08.2012 Jan Sammet - 32 -
No add load 2A
Inv OGOrbit gaps
Welcome2 x AMIS4, Front-End Sensing
29.08.2012 Jan Sammet - 33 -
No add load 2A
Inv OGOrbit gaps
Welcome2 x AMIS4, Back-End Sensing
29.08.2012 Jan Sammet - 34 -
No add load 2A
Inv OGOrbit gaps
Welcome Module Defects
29.08.2012 Jan Sammet - 35 -
• Four not understood module failures (broken TBMs) within four months
Investigated/excluded several possible explanations
• In particular ESD and DC-DC converters very unlikely to be the cause
• Most likely: EMI of adjacent set-up, when AC connectors (230V) are (dis)connected
• Many thanks to W.Erdmann and S.Streuli from PSI for their help!
Set-up adjacent to pixel modules
WelcomeTests with Low Threshold / High Occupancy
29.08.2012 Jan Sammet - 36 -
Software configuration:• Trimmed to low threshold (10 Vcal DACs)
Inefficiencies
Hardware configuration:• Four pairs of AMIS4_V8A / equivalent CAEN • Two modules powered by one converter pair• Back-end sensing• Plots are from M806
with testboard with CAEN with DCDC
Results:• Most dead pixels with Testboard, least with CAEN
• CAEN – Testboard = 108.7• DCDC – Testboard = 93.02• CAEN – Testboard = 15.68
No performance degradation due to DC-DC converters observable
