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Analog Baseband...
public project
  • Design Goal

The goal of this project is to design an analog baseband section suitable for 60 GHz receivers. The baseband section is required to select the desired channel and amplify the signal to a level that is near the full scale voltage swing of the ADC. The chain consists of a transimpedance amplifier, an active filter and a programmable gain amplifier. The overall chain's order is six. The LPF is of fourth order and both of the TIA and PGA are of the first order. 

  • Block Diagram

- Transimpendace amplifier : combines the signal and converts the input current coming from the beamfoarmer repeaters into voltage, so it requires low input impedance to sense the current. It contributes one pole to the overall system's transfer function and provides gain programmabiility.

- Low-pass filter : The LPF is of fourth order, and it's build using a cascade of two biquadratic cells, it's function is to select the desired channel while providing the required attenuation to the folding band of the interfereing channel.

- Programmable gain amplifier : It is the last stage of the chain. It provides gain programmability and a pole to the overall system's transfer function.

 

  • Proposed Specifications
Selectivity  6th order LPF
Real poles frequency 700 MHz
Complex poles Q-factor 1.45
Cut-off frequency 960 MHz
Cutt-off accuracy  10 %
In-band amplitude ripple 1.5 dB
Group delay < 4.5 ns
Gain range 0-20 dB
Gain step 1 dB
PAPR 7.8 dB
SDR 25 dB
IIP3 (0dB gain) 4.8 dBm
Input-Referred-Noise (20 dB gain) -142 dBm/Hz
  • Transimpedance Amplifier 

- For the TIA, a two stage miller compensated opamp topology have been used.

-The Cc performs pole splitting and the Rc is used to deal with the problem of the zero.

 

  • The CMFB Network

- The CMFB network is used to make the output common mode level well defined.

 

  • Low-Pass Filter

- A fourth order LPF is bulit using a cascade of two biquad cells with a source follower-based biquad topology.

 

  • Programmable Gain Amplifier.

- The used series shunt feedback yields to a high capacitive input impedance.

- The series shunt structure reduces the output impedance due to the feedback. So, the PGA can drive the ADC without affecting it's frequency and linearity performance.

 

  • The CMFB Network.

- The CMFB network is used to make the output common mode level well defined.

 

  • Team Members
    • Amir Victor
    • Hamdy Elshehaby
    • Maryam Hassan
    • Roshan Mohyeldeen
  • References

[1] S. D'Amico, A. Spagnolo, A. Donno, V. Chironi, P. Wambacq and A. Baschirotto, "A Low-Power Analog Baseband Section for 60-GHz Receivers in 90-nm CMOS," in IEEE Transactions on Microwave Theory and Techniques, vol. 62, no. 8, pp. 1724-1735, Aug. 2014, doi: 10.1109/TMTT.2014.2332877.

[2] S. D'Amico, A. Spagnolo, A. Donno, P. Wambacq and A. Baschirotto, "A 9.5mW analog baseband RX section for 60GHz communications in 90nm CMOS," 2011 IEEE Radio Frequency Integrated Circuits Symposium, 2011, pp. 1-4, doi: 10.1109/RFIC.2011.5940689.

Organization URL

https://www.fue.edu.eg

Description

The goal of this project is to design an analog baseband section suitable for 60 GHz receivers.

Labels

SSCS-22