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HomeWork 6 & 7
Fang Gong
[email protected]
HW6 Temporal correlation estimation for switching currents.
[Due on March 9]
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Problem Formulation:
Large circuit can be partitioned into relatively independent blocks, and
each block has multiple ports.
Each port can be modeled as a time-varying current source.
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This homework tries to extract the temporal correlation between
currents for a particular port.
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Given the peak current in every clock cycle at a particular port,
(1) compute the temporal correlation coefficient between currents:
– in adjacent clock cycles
– two clock cycles apart.
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(2) Also find the number of clock cycles that gives the maximum
correlation coefficient, which corresponds to the number of clock cycles
used to execute instructions.
Steps
1. Store the data in a MATLAB variable v1.
2. Shift the variable by one clock cycle and store it in a new
variable v2
3. Truncate v1 so that v1 and v2 has the same length.
4. Compute the correlation coefficient: corrcoef(v1,v2)
5. This gives the current correlation between adjacent clock cycles.
6.
7.
Shift v1 by two clock cycles and store it in a new variable v3.
Repeat steps 3-5 to get the correlation coefficients. This is the
current correlation two clock cycles apart.
8.
9.
Do this for different number of clock cycles, and plot the figure.
Pick out the number of clock cycles that gives the maximum
correlation coefficients.
3
HW7: Problem 1: Impedance of Package Power Distribution Network
[Due on March 13]
Observation
Point
1mΩ
5nH
2mΩ
600μΩ
30pH
equivalent
circuit
model
100nF
50nF
VRM
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
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Package
BGA ball
Die
Power Distribution Network (PDN) can be presented as above.
Voltage Regulator Module (VRM)
Package Plane Capacitance
Ball Grid Array (BGA)
Die Parasitic and On-die Decoupling Capacitance
(ZPDN) is the impedance of the PDN associated with the path from a
voltage regulator module (VRM) to the Die.
Problem:
•
Please plot the impedance (ZPDN) observed from die v.s. frequency.
•
Indicate that at which frequency ZPDN has its peak value and the magnitude of
peak value.
HW7: Problem 2: Designing Target Impedance of a PDN [Due on March 13]
1mΩ
5nH
ESL
2mΩ
600μΩ
30pH
100nF
C
50nF
ESR
VRM
Decaps
Package
BGA ball
Die
To lower the noise (voltage ripple), the goal of a power distribution
network system design is to have impedance (ZPDN) that is low with a
flat response over a desired frequency range.
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On-package decoupling capacitors are usually used and can be
modeled as a series combination of
the equivalent series inductance (ESL)
capacitance of the capacitor (C).
the equivalent series resistance (ESR).
Problem 2: Question 1
1mΩ
5nH
ESL
2mΩ
600μΩ
30pH
100nF
C
50nF
ESR
VRM
Decaps
Package
BGA ball
Die
Q1: Assume only one type of decap is available with C=200nF, ESL=100pH, and
ESR=60 mΩ and at most 30 decaps can be used.
Problem:
Using this type of decap, please try to show whether it is possible to make the
overall ZPDN less than 50 mΩ over frequency range from 2MHz to 1GHz?
If it can, show how many decaps can be used. If it cannot, explain why.
Problem 2: Question 2
1mΩ
5nH
ESL
2mΩ
600μΩ
30pH
100nF
C
50nF
ESR
VRM
Package
Decaps
BGA ball
Die
Q2: In addition to the decap used in (a), assume a second type of decap (from the table
below) can be used to make ZPDN less than 50 mΩ over frequency range from 2MHz to
1GHz.
Problem:
1.
Please choose one type decap out of the following candidates that can help you achieve
this goal.
2.
Plot the final overall impedance response over above-mentioned frequency range and
show how many for each type of decaps are used in your final design. (totally maximum
30 decaps are allowed.)
Candidates
A
B
C
D
E
C (nF)
100
50
50
10
10
ESR (mΩ)
60
60
25
60
25
ESL (pH)
150
100
100
100
100