第六讲 Low-Noise Amplifier 游飞博导/副教授，电子科技大学 feiyou@uestc.edu.cn
第六讲 Low-Noise Amplifier 游飞 博导/副教授，电子科技大学 feiyou@uestc.edu.cn
General Considerations Noise figure Figure 5.1.(a)LNA with input-referred noise voltage,(b)simplified circuit. [View full size image] Ay LNA LNA Rs 4KTRs n.in Vout 4kTRs ,家男家等有用男家家家年果市等年 (a NF n.out A (b) 4kTRs =1+ 只n 4kTRs
General Considerations Noise figure
Example 5.1: A student lays out an LNA and connects its input to a pad through a metal line 200 um long.In order to minimize the input capacitance, the student chooses a width of 0.5 um for the line.Assuming a noise figure of 2 dB for the LNA and a sheet resistance of 40 m/for the metal line,determine the overall noise figure.Neglect the input- referred noise current of the LNA. Figure 5.2.LNA with metal resistance in series with its input. LNA 4kTRs 4kTRL Rs RL out Metal Line V2. n,in +4kTRL NFtot 1+ AKTRs R=(200/0.5)×40m2/▣=162 =1+ 哈m RL 4kTRs Rs NFtot =2.79 dB. NFLNA+ R Rs
Example 5.1: A student lays out an LNA and connects its input to a pad through a metal line 200 µm long. In order to minimize the input capacitance, the student chooses a width of 0.5 µm for the line. Assuming a noise figure of 2 dB for the LNA and a sheet resistance of 40 mΩ/□ for the metal line, determine the overall noise figure. Neglect the inputreferred noise current of the LNA. RL =(200/0.5) × 40 mΩ/□ = 16Ω
Gain Gain个NF Nonlinearity个 [View full size image] 1x+02x283x2 4kTRs Rs Rs out LO (a) b 1 NFtot A品(V匠M+4kTRs)+V .mix A 4kTRs 1 1 2 IP.tot P mixer 1 = NFLNA+ nmix A品 4kTRs )))
Gain Gain↑ NF ↓ Nonlinearity ↑
Input Return Loss Figure 5.4.Constant-r contours in the input impedance plane. Im(Zin)4 1.22+j0.703 502 Zin-Rs 12 -10dB r= Zin+Rs -20dB -15 dB 2.0 Re(Zin} 1.02 1.22 502 1.065
Input Return Loss