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KAVOSHCOM RF Microelectronic LNA and Mixer Oscillator

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KAVOSHCOM August 15, 20152 Contents 1.Introduction 2.Basic concepts 3.Digital modulation, Spectral control, Detection 4.Multiple access standards, TDM, CDM, OFDM 5.TRx architecture 6.LNA and Mixer 7.Oscillator 8.Frequency Synthesizer 9.Power Amplifier

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KAVOSHCOM August 15, 20153 Section 6 6.LNA and Mixers a)LNA i.Input matching vs. NF ii.BJT vs. CMOS iii.BW enhancement b)Mixer i.BJT Mixers ii.CMOS Mixers iii.Noise in Mixers c)Cascaded stages

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KAVOSHCOM August 15, 20154 LNA Figures of Merit Frequency Noise Figure Linearity (P-1dB, IIP3) Bandwidth and Q Gain S21 Power Consumption Supply Voltage S-Parameters Gain S21 Input Matching S11 Output Matching S22 Reverse Isolation S12 Stability Image Rejection Capability

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KAVOSHCOM August 15, 20155 Typical Figures of Merit

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KAVOSHCOM August 15, 20156 LNA Design Input Matching Network Noise and Linearity Consideration Output Loading and Gain Output Matching Network Stability Differential Design

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KAVOSHCOM August 15, 20157 Noise Figure of LNA LNA, the first gain stage in the receive path its Noise figure directly adds to that of the system Duplexer Noise Figure ~ 2dB System Noise Figure=4dB LNA noise Figure =2dB 8dB

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KAVOSHCOM August 15, 20158 Noise Figure of LNA LNA=2dB using BJT: =2KTg m (shot noise) 4KTr b

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KAVOSHCOM August 15, 20159 Noise Figure of LNA For NF=2dB R eq < 29 Q1 must be relatively large and biased at a high current Finger structure reduces r b but increases capacitance Bandwidth reduction

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KAVOSHCOM August 15, 201510 Minimum Gain of LNA Defined by Three parameters: Loss of the image-reject filter Noise Figure of mixer IP3 of the Mixer For example: Filter loss=4~5 dB Mixer noise figure=10dB min. Gain=20dB Mixer IP3=+5dBm Input-referred noise is suppressed reasonable equivalent IP3 is maintained

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KAVOSHCOM August 15, 201511 Input and Output Matching Input Impedance is 50 because it comes out of the antenna Output Impedance can be>=50 whether it goes to IC The quality of the input matching is expressed by: Input Return Loss=20log|| =the reflection coefficient with respect to a source impedance R 0 For Impedance Matching:

KAVOSHCOM August 15, 201517 LNA stability Stern Stability Factor : If K>1 & 1 at all frequencies

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KAVOSHCOM August 15, 201518 LNA stability If S 12 0 then: K S 11.S 22