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Prototype LNA

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1 mW through source follower. 1 mW through biasing ... 6 dB is lost through source follower. 2nd generation uses integrated capacitive transformer ... – PowerPoint PPT presentation

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Title: Prototype LNA


1
Prototype LNA
  • Sent out for fabrication March 2002
  • Includes RF MEMS (FBAR) at output tank to
    provide narrowband filtering
  • Inductive source degeneration provides noiseless
    narrowband input impedance match
  • Source follower provides output impedance match

Vdd
Lchoke
FBAR
Vout
Vbias
Lg
Vin
Ls
2
(No Transcript)
3
Measured S Parameters
4
Measurement versus Simulation
  • Measured (_at_ 1.89 GHz)
  • S11 -13.44 dB
  • S21 6.77 dB
  • S12 -24.4 dB
  • S22 -7.35 dB
  • Simulation
  • S11 -10.73 dB
  • S21 12.61 dB
  • S12 -47.58 dB
  • S22 -11.81 dB

5
Performance Summary
  • Power 3 mW total (from 1 V source)
  • 1 mW through LNA
  • 1 mW through source follower
  • 1 mW through biasing
  • 1 dB Compression Point -18.5 dBm (simulation
    -19.6 dBm)
  • Power Gain 6.77 dB
  • Bandwidth 4 MHz centered at 1.89 GHz
  • Noise Figure to be measured (simulation
    3.5 dB)

6
What was learned
  • LNA results are close to simulation
  • Forward gain is degraded by capacitive parasitics
    from board.
  • Q of FBAR is decreased significantly
  • 2nd generation integrates all sensitive nodes on
    chip
  • 6 dB is lost through source follower
  • 2nd generation uses integrated capacitive
    transformer
  • On-chip gate inductor contributes noise and
    degrades forward gain
  • Accurate modeling of transistors and parastics is
    absolutely necessary
  • Lower power can be achieved by decreasing current
    through bias transistors, as well as using a
    passive output impedance matching network.

7
2nd Prototype LNA
NO FBAR NARROWBAND FILTERING IN SECOND STAGE
RF OUT
NO SOURCE DEGENERATION, INPUT MATCH BY NQS GATE
RESISTANCE
RF IN
INPUT IMPEDANCE MATCHING
shematic of LNA in receiver chain. The output
impedance matching network is not shown.
8
Simulated S Parameter Plots
S11
S21
16 dB
-39 dB
9
Simulated Performance Summary
  • S21 16 dB
  • S11 -39 dB
  • AV 30 dB
  • Bias Current 1.5 mA
  • Power 1.8 mW
  • Noise Figure 2.6 dB
  • Linearity (IP3) -17.3 dBm
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