RF CIRCUITS

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RF CIRCUITS
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Session Participants

• Sayf Alalusi
• Sam Blackman
• Chinh Doan
• Brian Limketkai
• Ian ODonnell
• David Sobel
• Johan Vanderhaegen
• Dennis Yee
• Robert Brodersen

• Ali Niknejad
• Manolis Terrovitis
• Robert Meyer

• Bob Frye
• Andrei Vladimirescu

3
W-CDMA Transmitter/Receiver
Basestation Transmitter
I
DAC
PA
Q
DAC
2 GHz
PLL
Mobile Receiver
I
ADC
LNA
ADC
Q
PLL
4
Transmitter DAC
I
DAC
Q
DAC

• DAC specifications
• 8 bits
• 100 MHz

Sam Blackman

• Design decisions
• Which type of DAC to implement?
• Binary weighted, unit element, segmented
• Is matching going to be a problem?
• How about SNR?

5
Transmitter LPF/Mixer
Johan Vanderhaegen

• LPF 2nd order Butterworth, f3db25MHz
• Mixer Gilbert cell
• I and Q channel are added in the current domain

6
Wherefore 50W?

• Originally a trade-off for coax cables
• Maximum power handling at 30W
• Minimum attenuation at 77W
• Is 50W still a good choice?
• Can the antenna operate correctly when its
  terminals are open-circuited?
• Can we design an on-board filter that has
  open-circuited terminals?

2 GHz
Ian ODonnell
Sayf Alalusi
7
PLL
I
ADC
LNA
ADC
Q
Chinh Doan
PLL

• Frequency synthesizer requirements
• Fixed frequency for direct downconversion
• Processing gain reduces effect of reciprocal
  mixing
• Correlation decreases RMS phase noise
• Relaxed requirements low power, fully
  integrated, CMOS implementation

8
Receiver Mixer

• Relaxed requirements allow for simpler designs
  consuming less power
• Switch sizes are kept small thus removing the
  need for an LO buffer
• Increased flicker noise due to small switches in
  the active mixer
• No flicker noise in passive mixer

9
Receiver ADC
I
ADC
LNA
ADC
Q
PLL
David Sobel

• Specifications SNDR 62 dB, fNYQ25 Ms/s
• ?D modulator
• 2-1-1 multi-bit cascade for low-OSR solution
• Projected total power dissipation lt10-15 mW
• ?D-assisted timing recovery

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Monolithic Passive Devices

• ASITIC software
• Example circuits
• VCO
• PA

Ali Niknejad
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Active CMOS Mixer Analysis

• Objective Analytical Design Methodology
• Noise Calculate noise contribution from all
  internal and external noise sources
• Intermodulation Distortion Fast evaluation of
  the intermodulation of the switching pair
• Express performance in terms of simple
  expressions and graphs of normalized parameters

Manolis Terrovitis