MOSFET-Only Wideband LNA with Noise Cancelling and Gain Opti(2)

全CMOS噪声抵消和增益优化的宽带LNA

capacitances and CRs is the signal source resistance and Lthe drain-bulk and drain-gate capacitance. R1 is the load resistance.

Figure 1. Common-Gate Stage.

1)Gain (1a)

(1b)

(1c)

2)Input Impedance

(2a)

where,

,

,

,

(2b)

(2c) 3)Noise Figure

(3)

where k is the Boltzmann constant ccapacitance, Woxis the oxide gate 1 and L1 are the transistor channel’s width and

length, respectively, T is the absolute temperature in Kelvin, γis the excess noise factor, kparameters, which depends on the size of the MOSFET f and αfare intrinsic process transistors [7, 8]. mon Source Stage

Figure 2. Common-Source Stage.

In the following equations gtransconductance and output impedance. The capacitances m2 and ro2 are the transistor’s ccgs2, cgd2, and db2 are the gate-source, gate-drain and drain-bulk capacitances, respectively. R2 is the load resistor. 1)Gain

(4a)

(4b)

(4c)

2)Input Impedance

(5)

3)Noise Figure

(6)

III.LNA

In the design of a wideband LNA there is an important choice to be made. A single-ended input simplifies the connection to the antenna and RF filters (they are usually single-ended) and avoids the need of a balun for the single to differential conversion (the balun usually has high loss and

degrades the NF significantly). A differential input leads to