All,
As I understand it, there is a Package model for VDD and VSS, and Randy
wants to add an on-die capacitance between VDD and VSS.
Randy has two choices using BIRD189 models:
1. A pin to pad PDN and a Buffer to pad PDN.
2. A pin to buffer PDN and add the on-die capacitance to the Pin to
buffer PDN
Here are the models
A pin to pad PDN and a Buffer to pad PDN.
[Interconnect Model] Pin2Pad
File_IBIS-ISS Pin2Pad.iss Pin2Pad
Number_of_terminals = 4
1 Pin_Rail signal_name VDD
2 Pin_Rail signal_name VSS
3 Pad_Rail signal_name VDD
4 Pad_Rail signal_name VSS
[End Interconnect Model]
[Interconnect Model] Buffer2Pad
File_IBIS-ISS Buffer2Pad.iss Buffer2Pad
Number_of_terminals = 4
1 Buffer_Rail signal_name VDD
2 Buffer_Rail signal_name VSS
3 Pad_Rail signal_name VDD
4 Pad_Rail signal_name VSS
[End Interconnect Model]
.subckt Pin2Pad PinVDD PinVSS PadVDD PadVSS
R1 PinVDD PadVDD R=.1
R2 PinVSS PadVSS R=.1
.end Pin2Pad
.subckt Buffer2Pad BufferVDD BufferVSS PadVDD PadVSS
R1 BufferVDD PadVDD R=.01
R2 BufferVSS PadVSS R=.01
C_on_die PadVDD PadVSS .1pF
.end Pin2Pad
Note that if you are going to have an on-die (Buffer to Pad) PDN, then
there must be some series resistance (and inductance), in addition to the
on-die capacitance, although the series resistance might be very small.
Also, there could be on-package capacitance, which I did not include here.
A pin to Buffer PDN.
[Interconnect Model] Pin2Buffer
File_IBIS-ISS Pin2Buffer.iss Pin2Buffer
Number_of_terminals = 4
1 Pin_Rail signal_name VDD
2 Pin_Rail signal_name VSS
3 Buffer_Rail signal_name VDD
4 Buffer_Rail signal_name VSS
[End Interconnect Model]
.subckt Pin2Buffer PinVDD PinVSS PadVDD PadVSS
R1 PinVDD BufferVDD R=.11
R2 PinVSS BufferVSS R=.11
C_on_die BufferVDD BufferVSS.1pF
.end Pin2Buffer
Walter
Walter Katz
<mailto:wkatz@xxxxxxxxxx> wkatz@xxxxxxxxxx
978.461-0449 x 133
Mobile 303.335-6156
From: ibis-interconn-bounce@xxxxxxxxxxxxx
[mailto:ibis-interconn-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Friday, February 9, 2018 11:18 AM
To: ibis-interconn@xxxxxxxxxxxxx
Subject: [ibis-interconn] My AR from Wednesday - drawing
Hello Everyone,
Here is a simple drawing to illustrate my question
from last Wednesday:
We can talk about this in the meeting.
Thanks,
Arpad
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