Effect of out-of-band terminations on intermodulation distortion in common-emitter circuits

Aparin, V.; Persico, C.

doi:10.1109/mwsym.1999.779549

Cited by 105 publications

(64 citation statements)

References 6 publications

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“…This relatively low frequency signal can be attenuated by keeping the impedance of the bias path at the amplifier input as small as possible at low frequencies. However, it has been shown that the optimum value of the impedance seen at low frequencies is not zero, but finite and complex [19]. Also, the second harmonic of the RF signal is fed from the output back to input via the collector-base capacitance, where it mixes with the fundamental tones thereby generating thirdorder IM distortion.…”

Section: Linearitymentioning

confidence: 99%

SiGe Radio Frequency ICs for Low-Power Portable Communication

Long

2005

Proc. IEEE

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Section: Linearitymentioning

confidence: 99%

SiGe Radio Frequency ICs for Low-Power Portable Communication

Long

2005

Proc. IEEE

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“…Recently, new design techniques were introduced for the linearization of bipolar transistor stages, which are based on the use of proper even harmonic terminations [5], [6]. The following nonlinear analysis shows how we obtain the required optimum out-of-band terminations for IM3 cancellation.…”

Section: Linearity Optimizationmentioning

confidence: 99%

“…The load impedance is not taken into account in the analysis, which is a fair assumption since the LNA stage is unilateral. To calculate the optimum out-of-band source terminations of this network, we use the expressions for IM3 as defined in [5], which state that the magnitude of IM3 is proportional to a factor , given by (16) where and , which is valid for small . The Taylor coefficients of the nonlinear collector current up to the third-order are defined as (17) The first term in is responsible for the direct third-order nonlinearity and the second term describes how the second-order nonlinearity mixes with the fundamental signal again, producing an indirect third-order nonlinearity.…”

Section: A Nonlinear Analysismentioning

confidence: 99%

“…However, also for the configuration in [4], a tradeoff still exists between linearity, gain, and current level. To overcome these limitations, recently new circuit techniques were introduced to improve the linearity of bipolar transistors at low current levels by proper even harmonic control through the use of out-of-band terminations [5], [6]. These latter techniques, based on the controlled cancellation of third-order intermodulation (IM3) products, offer more circuit design freedom to avoid tradeoffs in bias and linearity.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the design of unilateral dual-loop feedback low-noise amplifiers with simultaneous noise, impedance, and IIP3 match

Heijden

Vreede

Burghartz

2004

IEEE J. Solid-State Circuits

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Abstract-This work describes the theory and design of a nonenergetic dual-loop feedback low-noise amplifier (LNA) that provides maximum unilateral gain and simultaneous noise and impedance matching conditions. The dual-loop feedback is implemented in the form of transformer current-feedback and inductive series feedback (emitter degeneration). The current-feedback transformer is also used to neutralize the base-collector capacitance ( ), by combining it with a properly dimensioned shunt admittance at the collector output. The result is a single-transistor unilateral-gain amplifier with high isolation and good stability, eliminating the need for a cascode stage and thus enabeling the use of a lower dc-supply voltage. For the complete LNA, simple design equations are derived for the unilateralization, noise, and impedance matching requirements. Finally, second-harmonic tuning at the source improves the linearity without compromising the simultaneous noise and impedance match. To verify the presented theory, a 900-MHz hybrid Si BJT LNA has been implemented, which achieves 1.3-dB noise figure, 15-dB gain, 55 dB isolation, and +10 dBm IIP3 using a conventional double poly transistor, consuming = 2 5 mA at = 1 5 V.Index Terms-Linearity, low noise amplifier (LNA), negative feedback amplifier, noise matching, radio-frequency integrated circuit design, Si-SiGe analog circuit design, third-order distortion, third-order intermodulation distortion (IM3).

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“…, is used as a shunt resonant circuit. The main goal of this transmission line is to isolate the undefined second-harmonic impedance of the generator [6], behaving as a short circuit; however, it works as an open circuit for the fundamental component and, consequently, it does not affect the LNA performance. When this technique is used, the 1-dB power-gain compression, power gain, and noise figure are not altered, but IIP3 is enhanced by almost 1.3 dB, as compared with the first structure.…”

Section: Circuit Designmentioning

confidence: 99%