Freescale Semiconductor Confidential Proprietary. Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc. 2004

VBIC versus HICUMfor high-GHz, high Power

Applications

Ralf Reuter, Jens SchmidtRF/IF TechnologyInnovation Center EMEA

November 16, 2004

Bipolar User Meeting, Rev. 1November 12, 2004

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Background

High-GHz & High-Power Applications:

Noise parameter predictionHigh current modelingOptimum load- and source-impedance predictionCompression & Harmonics

S-Parameter simulation!!precise S11 for optimum source impedanceprecise S22 for optimum load impedanceprecise S21 for gain

Device for investigation:BiCMOS 0.18µfT/fmax ~ 110/130 GHzBVCE0 ~ 3 V, BVBC0 ~ 8 V

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Voltage Controlled Output Characteristics

VBIC HICUM

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Current Controlled Output Characteristics

VBIC HICUM

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Gummel Plot VCE Controlled

VBIC HICUM

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fT verus Collector Current IC

VBIC HICUM

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fmax versus Collector Current IC

HICUMVBIC

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Summary I

Nearly same modeling quality for VBIC and HICUMsmall advantage for HICUM at extremely high currents

not important for circuit designVBIC seems to be sufficient

A) Prove of model approach by large-signal measurementsB) Stability of model simulation time

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Load-Source Pull @ 40 GHz

f = 40 GHz, VCE = 2.0 V, VBE = 0.851 VFixed optimum load- and source impedance @ Pin = 0 dBmWe = 0.245 µm, Le = 10 µm, Ne = 1

0

2

4

6

8

10

-20 -15 -10 -5 0 5Pin [dBm]

Pou

t [dB

m],

Gai

n [d

B]

VBIC

0

2

4

6

8

10

-20 -15 -10 -5 0 5Pin [dBm]

Pou

t [dB

m],

Gai

n [d

B]

HICUM

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Optimum Impedances @ 40 GHz

f = 40 GHz, VCE = 2.0 V, VBE = 0.851 V, Pin = 0 dBmWe = 0.245 µm, Le = 10 µm, Ne = 1

(E95846, W10) 40GHz (0.25x9.9x1)

ZS (measured)ZS (simulated)ZL (measured)ZL (simulated)

VBIC (E95846, W10) 40GHz (0.25x9.9x1)

ZS (measured)ZS (simulated)ZL (measured)ZL (simulated)

HICUM

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Summary II

Poor S11 modeling for HICUM (low RB) over estimated gain

Poor S22 modeling error in optimum load > 50%

HiCUM took longer to simulateoften convergence problems in large circuits (ADS 2003C)

Needed:Model has to predict S-parameters

Modeling approach not only based on fT/fmaxS-parameters as optimization goal