Ansoft proprietary

The Next State-of-the-Art in Circuit Simulation

Samuel Mertens, Mary TolikasAnsoft Corporation

Ansoft proprietary

Requirements for the next state-of-the-art circuit simulator

• Consistency across analysis domains• Model compatibility• High capacity• High speed• Accuracy• Robust convergence

NEXXIMNEXXIM

Ansoft proprietary

Nexxim supports all required analyses

• DC• Transient• Harmonic Balance

– Single tone / Multi-tone• AC

– AC / Time varying AC

Netlistor

Schematic

NEXXIMSimulation

Engine

Post-processing

• Noise– DC / Time-varying

• Sweeps– Variables– ALL model parameters

Ansoft proprietary

Nexxim providesresult consistency across domains

All analyses, whether time-domain or frequency-domain, use the same models and simulate

from the same netlist.* Gilbert cell mixer.SUBCKT GilCellMix 12 6 22 15 R6 9 28 20 R3 17 2 50 C3 0 2 1.0uF C1 12 10 1uF L1 10 21 0.5nH C4 15 7 1uF QBJT14 14 11 5 BJTM5 area=1QBJT10 6 24 17 BJTM3 area=1QBJT11 17 18 13 BJTM3 area=1QBJT2 9 11 20 BJTM3 area=1.model BJTM1 NPN Bf=1.30035647e2.ends GilCellMix

X1 3 4 Vif 7 GilCellMixV_SRC1 4 0 5.0 R2 7 5 50 RVif Vif 0 50 R3 3 2 50 V_LO 5 0 sin(0 0.1 1.75e9 0 0)V_RF1 2 break sin(0 0.0 2e9 0 0)V_RF2 break 0 sin(0 0.0 1.65e9 0 0).tran 0.01e-9 30e-9 0 3e-9.plot tran v(VIF)*HB:HB2 MaxOrder=4 Freq[1]=2000 MHz Order[1]=15.end

Time Domain

FrequencyDomain

Ansoft proprietary

Nexxim supports a variety of models•Passives

Resistors, Inductors, Capacitors•Independent/Dependent Sources•S-parameter elements (N-ports)•Transmission Lines (W elements)•Diodes

JUNCAPGeometricNon-GeometricFowler-Nordheim

•BJTsGummel-Poon & extensionsVBICPhilips MEXTRAM 503 / 504HiCUMHBT

•MOSFETsSchichman – HodgesBSIM3BSIM4Philips MOS 9 / MOS 11SOIEPFL – EKVHiSIM

•JFETs/MESFETsSPICECurticeStatzTriquint

•IBIS models

Ansoft proprietary

HFSS3D EM analysis

DESIGNERIntegrated Environment:

• Schematic Capture• Layout / Planar EM

• System analysis

Nexxim integrates with advanced EM and system tools

NEXXIMCircuit Simulation

Ansoft proprietary

Nexxim achieves highcapacity and speed

5 x12 x

BJT Mixer25 transistorsup to:1023 harmonics610,304 data pts.

MOS Mixerup to:1536 transistors856,256 data pts.

Ansoft proprietary

Nexxim offers highaccuracy at high speed

7 x

CompetitorNexxim

7 x7 x

CompetitorNexxim

NCSU sqrt example1188 BSIM3 transistorsTransient analysis

Ansoft proprietary

Nexxim offers high capacity and speed

Front-end for Bluetooth radio

2486 MOSFETs13 BJTs

24 minutes using Ansoft simulator3-tone Harmonic Balance

Ansoft proprietary

Nexxim offers robust convergence

Frequency Divider

Harmonic Balance Analysis

Large number of harmonics required to capture square-wave output

Nexxim converges in less than 1 minCompetitor does not converge

Ansoft proprietary

Nexxim integrates with system level design

0

0

0

0

0 0

gnd_psl_dff1_1vdd_psl_dff1_1

vdd_psl_dff1_1

gnd_psl_dff1_1

gnd_ANDcml_1vdd_ANDcml_1

vdd_ANDcml_1

gnd_ANDcml_1

vdd_psl_dff1_1

vdd_ANDcml_1

gnd_ANDcml_1

vdd_ANDcml_1

vdd_preamp_1

gnd_preamp_1

RbR

DbD

clkclkb

Qb

Q

bias

U1presclr_DFF

W_dff1=2u

AAbBBb

bias

QbQ

U2CML_AND

W_ANDcml=8u

inbin

biasout

outb

U17Pre_Amplifier

W_preamp_n=8uW_preamp_p=10u

W_preamp_src=30u

RbR

DbD

clkclkb

Qb

Q

bias

U18presclr_DFF

W_dff1=2u

AAbBBb

bias

QbQ

U19CML_AND

W_ANDcml=8uRbR

DbD

clkclkb

Qb

Q

bias

U20presclr_DFF

W_dff1=2u

RbR

DbD

clkclkb

Qb

Q

bias

U21presclr_DFF

W_dff1=2u

RbR

DbD

clkclkb

Qb

Q

bias

U22presclr_DFF

W_dff1=2u

RbR

DbD

clkclkb

Qb

Q

bias

U23presclr_DFF

W_dff1=2u

RbR

DbD

clkclkb

Qb

Q

bias

U24presclr_DFF

W_dff1=2u

AAbBBb

bias

QbQ

U25CML_AND

W_ANDcml=8u AAbBBb

bias

QbQ

U26CML_AND

W_ANDcml=8u AAbBBb

bias

QbQ

U27CML_AND

W_ANDcml=8u AAbBBb

bias

QbQ

U28CML_AND

W_ANDcml=8u

inbin

biasout

outb

U29Pre_Amplifier

W_preamp_n=8uW_preamp_p=10u

W_preamp_src=30u

M183

L=0.5uW=8uM=1

nch

M184

L=0.5uW=30uM=1

nch

10k

10k

V1277DC=1VO=1VA=0.5FREQ=f_clkTHETA=0

V1280DC=1VO=1VA=0.5FREQ=f_clkTHETA=180

+-

V1281DC=0 +

-

V1284DC=0 +

-

V1285DC=0

+-

V1288DC=2.5

+-

V1293DC=0 +

-

V1294DC=0 +

-

V1295DC=0

VV

V

V

V

V

V V V

V

ps_swalo2

ps_swalo1

to_asyn

bias

dff1_o1

clk

clkb

asyn_o3

div64_65

div64_65b

asyn_o2asyn_o1

bias_ANDcml

bias

bias

modsel_o

bias_ANDcml

real_2p5v

bias

bias_ANDcml

B=High, P=65B=Low, P=64

Starting Time + Bias Transient ~10.5nsStarting Time + Bias Transient ~10.5ns

PLL System Design For 1.8GHz GSM

Ansoft proprietary

Nexxim offers high capacity without loss of accuracy

SRAM cell

47,399 MOSFETs62,000 devices

Competitor does not provide the capacity “Approximate Spice” simulator does not provide the accuracy

422 seconds in Nexxim

Ansoft proprietary

Nexxim encapsulates technology advances in software engineering

State-of-the-art software engineering– C++ code from the ground up– Templated C++ code for all analyses– Automatic model compilation

User-defined models justas fast as library models

Ansoft proprietary

Nexxim encapsulates technology advances in numerics

Advanced Ansoft-proprietary numerics– New variable timestep integration formula for

Transient Analysis – New preconditioners for Harmonic Balance– New sparse matrix package that is faster than

industry standard

Ansoft proprietary

Nexxim offers faster preconditioned Krylov methods for HB

10x

These methods are industry standard for HB but are limited!

Ansoft proprietary

Nexxim advantages

• Higher capacity and speed for Harmonic Balance- Single tone- Particularly for multi-tone

• Robust convergence• Unique transient analysis features

- Improved error control- Novel integration techniques

• Consistency of results across domains- All analyses, whether time- or frequency-domain, use the same models

and simulate from the same netlist• Integration to EM tools