# hw9 - 1 = 123 μ m, W 2 = W 3 = 75 μ m, V DD = 3 . 5 V, V...

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University of California, Berkeley Fall 2011 EECS 142/242M Prof. A. Niknejad Problem Set 9 Due Wednesday Nov. 23, 2011 IF 1kΩ 100nF 1nF 50Ω V A v s v o V CC = 5V I Q = 1mA 300Ω 50Ω 1. Consider the single transistor BJT mixer shown above. The LO frequency is 700MHz and the IF frequency is 100MHz. (a) Derive the large signal operating point of the circuit when driven by the LO alone ( v o ). The LO amplitude is 100mV. (b) Calculate the conversion gain of the mixer for a low-side LO injection. What is the image rejection? (c) Calculate the LO and RF feedthrough at IF. (d) Plot the conversion gain versus the LO amplitude. (e) Verify your results with ADS or SpectreRF (ideal npn transistor). (f) Recalculate the conversion gain when the mixer is operated in second-harmonic mode. (Note the LO is run 350 MHz) (g) ( 242M )Simulate the IIP3 and noise of the circuit for the nominal LO amplitude (ADS/SpectreRF) .

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V LO + V b 2 V b 2 L 1 L 2 L 3 V b 1 C 1 R L C L V DD M 1 M 2 M 3 v o v s 2. All devices are minimum channel 0 . 25 μ m devices. L 1 = 1 nH, L 2 = 35 nH, L 3 = 9 . 2 nH, C 1 = 689 fF, C L = 10 pF, R 0 = 50Ω, R L = 200Ω, W
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Unformatted text preview: 1 = 123 μ m, W 2 = W 3 = 75 μ m, V DD = 3 . 5 V, V b 1 = . 68 V, V b 2 = 1 . 5 V, V LO = 300 mV. The transistor is modeled by: model n25 mos1 type=n kp=260u vto=.4 tox=4n lambda=.1 cgso=.1p cgdo=.1p (a) Estimate the down-conversion power gain for the mixer for an input signal at 2 GHz with the LO drive at 2 . 1 GHz. (b) Verify your results using PSS and PXF in SpectreRF or HB in ADS. (c) Estimate the LO and RF port leakage? Conﬁrm with simulation. (d) ( 242M ) Simulate the SSB NF using PSS/PNoise or HB. How much of the noise contribution is from noise centered about the ﬁrst, second, and third LO harmonic? (e) ( 242M ) Convert the output signal to a diﬀerential signal. What are the advantages and disadvantages? Verify with simulation. (f) ( 242M ) Convert the mixer into a fully balanced architecture. Recalculate the conversion gain, noise ﬁgure, LO and RF port leakages, and verify with simulation. 2...
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## This note was uploaded on 01/12/2012 for the course EECS 142 taught by Professor Ee142 during the Fall '04 term at Berkeley.

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hw9 - 1 = 123 μ m, W 2 = W 3 = 75 μ m, V DD = 3 . 5 V, V...

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