LARGE-SIGNAL NETWORK ANALYZER … NETWORK ANALYZER MEASUREMENTS AND THEIR USE IN ... • tuning of...
Transcript of LARGE-SIGNAL NETWORK ANALYZER … NETWORK ANALYZER MEASUREMENTS AND THEIR USE IN ... • tuning of...
Ewout Vandamme (Agilent Technologies, NMDG),Wladek Grabinski (Motorola, Geneva),Dominique Schreurs (K.U.Leuven), andThomas Gneiting (ADMOS)
LARGE-SIGNAL NETWORK ANALYZER MEASUREMENTS AND THEIR USE IN
DEVICE MODELLING
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Outline
• Large-Signal Network Analyzer (LSNA) technology• Advantages of using LSNA for device modelling engineers• LSNA measurements
• de-embedding• implementation in CAE tool (iccap)• measurement and simulation results• tuning of model parameter to LSNA measurements
• Conclusions
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Agilent’s Large-Signal Network Analyzer technology
Cal Kit,e.g. LOS, LRRM, etc.
Power Std
Phase Std
Calibration Standards: a1b1
a2b2
i1v1
or, equivalently,i2
v2
(a)
• RF bandwidth: 600 MHz - 20 GHz• max RF power: 10 Watt• IF bandwidth: 8 MHz• Needs CW or periodic modulation
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• 2-port Device-Under-Test (DUT) under periodic excitation• e.g. transistor excited by a 2.4 GHz tone with an arbitrary output
termination
• All current and voltage waveforms are represented by a fundamental and harmonics
• Spectral components Xh = complex Fourier Series coefficients of the waveforms
CW class of signals measured with LSNA
Freq. (f0=2.4 GHz)1*f0 2*f0 3*f0 4*f0DC
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LSNA measurements: time domain, frequency domain or combination of both (e.g. envelope in modulation)
= ∑=
H
h
tfhjh eXtx
0
2Re)( π
∫−
−=1
0
2)(2f
tfhjh dtetxfX π
frequencylfundamentaperiodf == /1
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Advantages of using the LSNA in device modelling
• Measure the following characteristics of your DUT making a singleconnection, using one measurement setup (the LSNA)
• DC,• Small-signal (Scattering parameters), and• Large-signal behaviour
• Verify the model accuracy of your device under realistic operation conditions
• power amplification• high-speed switching
• Identify modelling problems at a single glance• LSNA measurements, e.g., immediately reveal weaknesses in capacitance and
charge models
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Use of LSNA measurements in CAE tool (iccap)⇒⇒⇒⇒ model verification, optimisation (and extraction)
ICCAP specific input
ADS netlist. Used, a.o., to impose themeasured impedance to the output ofthe transistor in simulation
sweep of Power Vgs Vds Freq
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Use of LSNA measurements for simulation (1/2)
Measurements RF de-embedding
V1m,dc I1m,dcV2m,dc I2m,dc
a1c b1ca2c b2c
v1c i1cv2c i2c
calibrated
V1,dc I1,dcV2,dc I2,dc
⇒LSNA accounts forcable resistances
v1c i1cv2c i2c
v1d i1dv2d i2d
⇒
⇒
@ f0, 2*f0, …
Reference planes beforeand after de-embedding
⇔
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De-embedding intermezzo (1/2)
0 0.5 1 1.5 2
- 3
- 2
- 1
0
1
2 beforeafter
de-embedding
Time/period
Gate
curre
nt / m
A
Equivalent circuit of the RF test-structure, including the DUT and layout parasitics
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De-embedding intermezzo (2/2)
Detailed view on the layout of the RF MOSFET
for minimum influence of pad parasitics
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Use of LSNA measurements for simulation (2/2)
RF de-embedding Simulations
v1c i1cv2c i2c
v1d i1dv2d i2d
⇒
v1d i1dv2d i2d
Comparemeasurements:
with simulations:v1s i1sv2s i2s
⇒
Rde1 and Rde2 are de-embedding resistances (in dc path)The load impedance ZL at f=n*f0 equals 50 Ω if a2n<-50 dBm
Reference planes beforeand after de-embedding
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Input capacitance behaviourVgs,dc=0.9 VVds,dc=0.3 V Vds,dc=1.8 V
Input loci turn clockwise, conform i=C*dv/dt
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Dynamic loadline & transfer characteristicVgs,dc=0.3 VVds,dc=0.9 V
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Dynamic loadline & transfer characteristicVds,dc=0.9 V Vgs,dc=0.9 V
DC operating point if RFnot present ⇒⇒⇒⇒ self-biasing
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Dynamic loadline & transfer characteristicVgs,dc=1.8 V
Cable resistance + Rde2 loss
Vds,dc=0.9 V
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Intermezzo (1/2): extrapolation example SiGe HBTModel parameters extracted using DC measurements up to 1 V
100 200 300 400 500 600 700 8000 900
-0.002
-0.001
0.000
0.001
-0.003
0.002
time, psec
i1sts
i1mts_de
100 200 300 400 500 600 700 8000 900
0.6
0.7
0.8
0.9
1.0
1.1
0.5
1.2
time, psec
v1sts
v1mts_de
100 200 300 400 500 600 700 8000 900
1.3
1.4
1.5
1.6
1.2
1.7
time, psec
v2sts
v2mts_de
100 200 300 400 500 600 700 8000 900
0.000
0.002
0.004
0.006
-0.002
0.008
time, psec
i2sts
i2mts_de
SiGe HBT Vbe= 0.9 V; Vce=1.5 V; Pin= - 6 dBm; f0= 2.4 GHz
simul.meas.
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Intermezzo (2/2): extrapolation example SiGe HBTMeasured and simulated DC characteristics
Measurement Simulation
SiGe HBT - DC characteristics
0.2 0.4 0.6 0.8 1.0 1.2 1.40.0 1.6
-0.010
-0.005
0.000
0.005
0.010
0.015
0.020
-0.015
0.025
VbDC
DCmeas1..Ice
0.2 0.4 0.6 0.8 1.0 1.2 1.40.0 1.6
-0.010
-0.005
0.000
0.005
0.010
0.015
0.020
-0.015
0.025
VbDC
i2.i
Alcatel Microelectronics and the Alcatel SELStuttgart Research Center teams are acknowledged
for providing these data.
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AM to AM (gain) and AM to PM versus input power
Vds,dc=Vgs,dc=1.2 V
1 dBcompression
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Drain current & gate voltage time domain waveforms
Vgs,dc=0.3 V
“Class C” Class AClass AB
Vgs,dc=1.2 VVgs,dc=0.9 VVds,dc=0.9 V
vinvin
vin
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Effect of operating regime on dissipated power in the DUT, load, and DC power supply — class AB
Vds,dc=0.9 V, Vgs,dc=0.9 V
RFoutput powerat f=f0
Instantaneouspower dissipatedin DUT
Powerdelivered byDC supply
PAE=37 %
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Effect of operating regime on dissipated power in the DUT, load, and DC power supply — “class A”
Vds,dc=0.9 V, Vgs,dc=1.8 V
RF output powerat f=f0
Instantaneouspower dissipatedin DUT
Powerdelivered byDC supply
PAE=11 %
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Tuning of model parameters to LSNA measurements
before
after
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LSNA measurements in device modellingConclusions:• Unique tool for complete large-signal model accuracy assessment
under realistic RF or microwave signals• information on amplitude and phase
• Reduce number of design cycles and reduce manufacturing costs through better device models, thus more optimal designs
• Optimize model parameters to LSNA measurements• Benchmark various device models, e.g.,
• BSIM, MM11, EKV, …• Gummel-Poon, VBIC, MEXTRAM, HICUM, ...
• Build confidence in your model
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Contact
• For info on LSNA technology, visithttp://www.agilent.com/find/lsna
• Soon, a measurement and consulting service related to Large-Signal Network Analyzer Technology will be available through the ‘NMDG’group in Belgium. For info, you need to contact NMDG directly atemail: [email protected], ortel.: +32 - 3 - 890 46 16