simulation-iss4

SYNERGIE CADConfidential


Design EngineeringSimulation Overview - Tool Set

• ANSYS HFSS software is the industry-standard simulation tool for 3-D full-wave electromagnetic field simulation and is essential for the design of high-frequency and high-speed circuit design.

– Provides accuracy for the design of high-speed circuits, test sockets, PCB interconnects, high-frequency components and RF/microwave components.

– Evaluate signal quality, including transmission path losses, reflection losses due to impedance mismatches, parasitic coupling and radiation.

– Visualize 3-D electromagnetic fields.

• ANSYS SIWave to analyse complete designs (includes multiple, arbitrarily shaped power/ground layers, vias, signal traces and circuit elements).

– Perform complete signal-integrity and power-integrity analysis from DC to beyond 10 GHz.

• Extract matrix parameters (S,Y, Z parameters), of signal nets and power distribution networks directly from EDA layout databases*.

• Aids in the identification of signal-integrity and power-integrity problems and is critical to first-pass system success.

* ODB++ is used as a common transfer method. It must be verified if the ODB++ file created by a particular package is compatible.


SimulationEDA Data Import

• ODB++ data files from the EDA Layout tool are directly imported.– Synergie-Cad can also provide simulation as a separate service.

• Measurement ports are place at the required points on the layout• Extraction of matrix parameters (S,Y, Z parameters) for analysis.• Cut-out sections of the layout to perform detailed 3D full-wave simulation of

High-frequency and RF/microwave areas.

Verigy 93K 9.5”, Vertical Probe Card, 32 Layer


Simulation - Signal Integrity Matrix Data (S,Y,Z, Parameters) Analysis

Transmission and Return Loss Signal Isolation

RF, Inductance and Capacitance Measurements

RF, Impedance, VSWR, Matching


Simulation - Signal IntegrityTDR Analysis

Open circuit seen:~7ns / 2 (return time of signal path) = ~3ns

Disturbance from Components

Tester pogo, t = 0ns


Simulation - Signal IntegrityMatrix Data Exported for use with Circuit

Simulators

• Terminal data exported• Port[1] = N1_1022• Port[2] = P1_1022• Port[3] = N2_1022• Port[4] = N1_1025• Port[5] = N2_1025• Port[6] = N1_1021• Port[7] = N2_1021• Port[8] = N1_1024• Port[9] = N2_1024• Port[10] = P2_1022• Port[11] = P1_1025• Port[12] = P2_1025• Port[13] = P1_1021• Port[14] = P2_1021• Port[15] = P1_1024• Port[16] = P2_1024

S7,6

Net: n1021Net: p1021

S6,6

S13,13

S7,7

S14,14

S14,13

Port[6] = N1_1021 Port[7] = N2_1021

Port[13] = P1_1021 Port[14] = P2_1021

Example, Net 1021

Touchstone S-Parameter data files


Example Simulation - Signal IntegrityOptimised Tapered RF Transformation

Optimised RF tapered transmission lineimpedance transformation, wideband, up to 30GHz.


Simulation – Usage Scenario #1

• Simulate the performance of standard cantilever needle at RF frequencies.

• The complete needle assembly, epoxy ring and PCB is included in the model.

Port 1 (S1)Needle Tip

Port 2 (S2)PCB launch track

Simulation results.Freq. sweep: 1GHz to 10Ghz.



• Model of the needle assembly used to understand the inductance of a cantilever needle at ~920MHz.

• S-Parameters simulated for S11, S22.


• BGA devices often require, micro vias to allow routing from pads on internal rows.

• In the cases where high speed signal pads are located on internal rows of the BGA, PCB traces must use a micro via to an internal layer.

• Simulation used to help optimise the via performance.• Detailed simulation can be performed on the final design data, as shown on

previous slides.

Field strengtharound the via.

Transmission and return loss performance

Laser via model.



Example Simulation - Signal IntegrityOptimised 50 ohm Via, Transmission and

Reflection Loss



• Possible to simulate and include as part of a larger simulation the performance of springs pins from a socket body or vertical probe head.

0

1

2

3

4

5

0 1 2 3 4 5 6 7Frequency (GHz)

Indu

ctan

ce (n

H)

-3

-2

-1

0


Inse

rtion

Los

s S2

1(dB

)

-60

-50

-40

-30

-20

-10

0


Ret

urn

Loss

S11

(dB)

Fig.1 Inductance

Fig.2 Insertion Loss Fig.3 Insertion Loss



• Multiple ports can be used (limited by physical RAM).• A differential 4 port structure; Allows mutual coupling effects

to be included in the S-Parameter model.

Port 4

Port 2

Port 3

Port 1


Simulation – Exported Data

• S-Parameter data file can be provided to customers, to allow in circuit simulation of the PCB before it is manufactured.

• Allows for confidence in the PCB layout and design before committing to the manufacture.

• Can save time and cost, if in the unlikely event a problem is found on the PCB after manufacture during functional test.

! Touchstone file from project RF-probe! Exported from HFSS 12.0.0# GHZ S DB R 50.000000! Modal data exported! Port[1] = 1:1! Port[2] = 2:11.000000000000000E+000 -1.591625431137832E+001 6.038651181469610E+001 -1.717771359540705E-001 1.574416881357343E+002 -1.717771359776334E-001 1.574416881357361E+002 -1.591195795430505E+001 7.239763240570214E+001 ! Gamma ! 3.208151732005790E-001 3.325143588579720E+001 5.466199417260070E-001 2.153677718539890E+001 ! Port Impedance 5.000000000000000E+001 0.000000000000000E+000 5.000000000000000E+001 0.000000000000000E+000

1.020000000000000E+000 -1.576155621619889E+001 5.985904360802454E+001 -1.766716037997347E-001 1.570001641968290E+002 -1.766716038225167E-001 1.570001641968333E+002 -1.575655129063723E+001 7.207979692165326E+001 ! Gamma ! 3.255003515711610E-001 3.391460264595060E+001 5.522104634251370E-001 2.196188115903890E+001 ! Port Impedance 5.000000000000000E+001 0.000000000000000E+000 5.000000000000000E+001 0.000000000000000E+000







Signal Integrity Applications using S-Parameters

– Single port• Measure impedance• Model interconnections• Smith charts – measure complex impedance by frequency.

– Two port• Return loss - losses due mismatches• Transmission line impedance, electrical length, losses.• Cross talk at any frequency.

– Four ports, multiple ports• Complete coupled line characterisation, single ended, differential,

return losses, transmission losses, impedance, electrical length.


Simulation - Power IntegrityBasic Requirement: Target Impedance

• The Impedance looking in the DPS from the device should be kept low over a broad frequency range.

• The Desired Frequency Range and Impedance Value is referred to as the Target Impedance.

DUTDPS

I

V Z


Simulation - Power Integrity

• Selecting the correct capacitance values is critical.• Capacitors selection from a library of capacitor models.• S-Parameter models can also be used.


Simulation - Power Integrity

• However.. calculation of values alone is not enough.• The effects of the layout must be taken into account.

CalculatedSimulated


Simulation - Power Integrity Analysis of Complete PCB Model

• Library of S-Parameter models for capacitor and inductors.• Passives are fitted and at the SMD pads• Entire PCB layout including passive is simulated. • Simulated Matrix Data (S,Y,Z, Parameters) output.


Simulation - Power Integrity Placement effect on Target Impedance

1KHz 1MHz 100MHz GHz

BulkCapacitors

CeramicCapacitors

Planes

• The effect of the placement and layout must be included in the overall model.

• Optimisation of the placement of components is required to minimise plane resonances.

• Optimisation of capacitor type / placement for the required performance over the desired frequency range.

• Optimisation of the layout to improve performance.– Inductance loops– Via length– Plane impedance


Example Simulation - Power Integrity Resultant Matrix Data (S,Y,Z, Parameters)

Impedance of power plane only with no decoupling

Power impedance with decoupling included


Simulation - Power Integrity Effect of Decoupling Network on Voltage Drop @

DUT

• Transient simulation to verify the effectives of the decoupling network.

• Circuit simulation of power supply using extracted board S-Parameters and decoupling.

• Cascade S-Parameter blocks to include any bulk decoupling of WPI and PC, for example.

Power supply model

DUT current load


Simulation - Power Integrity Effect of Decoupling Network on Voltage Drop @ DUT (cont.)

• Transient simulation to verify the effectives of the decoupling network.

• Power supply models of the tester hardware provided by the tester manufacturer.

• Simulate and verify the effects of a current transient on the overall network.


Thank You

simulation-iss4

Documents

synergie cad confidential

complete signalintegrity

signal traces

signal nets

signal quality

identification of signal

wave simulation of high

powerintegrity analysis