1 10 th October 2007Luciano Musa Considerations on readout plane IC Area (die size) 1-2 mm 2...
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Transcript of 1 10 th October 2007Luciano Musa Considerations on readout plane IC Area (die size) 1-2 mm 2...
110th October 2007 Luciano Musa
Considerations on readout plane
IC Area (die size)
• 1-2 mm2 /channel
• Shaping amplifier 0.2 mm2
• ADC 0.6 mm2 (estimate)
• Digital processor 0.6 mm2 (estimate)
• in the following we consider the case of 1.5mm2 / channel • 64 ch / chip ~ 100 mm2
Area of the chip on the PCB: 14 x 14 mm2 / chip ~ 3 mm2 / pad
PCB dimensions < 40 x 40 cm2 ~53000 pads, ~800 FE chips / board
210th October 2007 Luciano Musa
PCB topology and layer stack-up
Pad layerPad signals routing
det gnd
Digital signals Ignd
vddDigital signals II
gnd
8-layer PCB
Considerations on readout plane
Analogue PWR planes
Digital PWR planes
amplifiers
ADCs
Digital Processing
Chip floorplan
Flip-chip mounted
PCB
310th October 2007 Luciano Musa
Considerations on readout plane
Power consumption
• amplifier 8 mW / channel
• ADC 30 mW / channel
• Digital Proc 4 mW / channel
• Power regulation and links 10 mW / channel
• duty cycle: 1%
• average power / channel ~ 0.5 mW / channel
• average power / m2 167 W
410th October 2007 Luciano Musa
VRMIN OUT
L1
C1
L2
TRAPLocal decoupling networkVRM
IN OUTL1
C1
L2
TRAPLocal decoupling network
Considerations on readout plane
Readout Board power delivery network
Large storage capacitors
RO CHIP
VRM can be turned off
ON/OFF
Model used to evaluate the impedance of the local power delivery network
Impedance (W) versus frequency for the local power delivery network connected to the RO chip through a power plane with zero inductance.
High optimization of local decoupling network is required
510th October 2007 Luciano Musa
121 FEE Cards
TPC Low Voltage Distribution Scheme
115A max
115A max
115A max
DIGITAL
ANALOGUE
DIGITAL
Bus Bar pair (positive + return line)
Bus Bar pair
40m
Wiener power supplies
Analogue 4.0 60 60 100
Digital 3.3 133 194 200
Voltage
on load
(V)
I stdby
(A)
I max
(A)
Bus bar
Section
(mm2)
Bus Bar
description
TPC endplate
What is the
transient
response of the
bus bar?
R = 2 x 6.8 mV = 816mV
R = 2 x 3.4 mV = 1.32V
L ~ 11H
610th October 2007 Luciano Musa
Regulator
100 µF 1 µF
Power Supply
10 × 100 nF
ALTRO
4 s peaking time
Standby power
(15A / s)
60A
Dynamic Digital Current Consumption
3.3V 2.5V
710th October 2007 Luciano Musa
Regulator
100 µF 1 µF
Power Supply
10 × 100 nF
ALTRO
100 s peaking time
Standby power
Dynamic Digital Current Consumption
(0.6A / s)
60A
3.3V 2.5V
810th October 2007 Luciano Musa
C R
Test Configurations
Configuration A: R = C=0
Configuration B: R=25mC=0;
Configuration C: R=25mC=70mF
Configuration D: R = C=70mF
Test setup
ILoad
time
ITHigh
40m
Wiener
PL500
160mm2
multi-strand copper barElectronic Load
HP6050A – 6050BVPS VLoad
I
h=1cm
= 2.110-8 m
L = 11H
910th October 2007 Luciano Musa
62.6V
0.8ms
680mV
I (A) Freq (Hz) THIGH (ms) Slew rate (A/s)
60 100 4 10
Test Parameters
Measurement 1 (configuration A )
A sudden interruption of the current can damage the Front End Cards !
1010th October 2007 Luciano Musa
I (A) Freq (Hz) THIGH (ms) Slew rate (A/s)
41.6 100 4 10
Test Parameters
A current swing of 41.6A produces
a transient voltage of ~1.8V
480mV
1.28V
0.78V
Measurement 2 (configuration B )
L/R ~ ms
Voltage drop across the bar for a current
swing of 60A
• V low load (dc) 0.90 V
• V high load (dc) 1.32 V
• V (transient) 3.40 V
1110th October 2007 Luciano Musa
I (A) Freq (Hz) THIGH (ms) Slew rate (A/s)
41.6 100 4 10
“ 1000 0.1 “
Test Parameters
70mF in parallel to the electronic load assorbes the large transient spikes
Measurements 3 (configuration C )
0.95V
0.30V
A
B
A B
B
A
ALICE TPC conditions
1210th October 2007 Luciano Musa
I (A) Freq (Hz) THIGH (ms) Slew rate (A/s)
60 10 40 10
Test Parameters
Measurements 4 (configuration D )
2V
1310th October 2007 Luciano Musa
I (A) Freq (Hz) THIGH (ms) Slew rate (A/s)
60 100 4 10
“ 1000 0.1 “
Test Parameters
A
B B
A
A B
3.3V
2.5V
100s
Measurements 5 (configuration A + sense wire )
The sensing feedback is not fast enough to react to the load variations
ALICE TPC conditions
1410th October 2007 Luciano Musa
Measurements 6 (configuration C + sense wire )
I (A) Freq (Hz) THIGH (ms) Slew rate (A/s)
41.6 100 4 10
Test Parameters
1.2V
The sensing feedback is not fast enough to react to the load variations
1510th October 2007 Luciano Musa
220mV
100s
Measurements 7 (configuration C + sense wire )
I (A) Freq (Hz) THIGH (ms) Slew rate (A/s)
41.6 1000 0.1 10
Test Parameters
The sensing feedback is not fast enough to react to the load variations
C = 100mF