A low-power 0.4-22GHz CMOS cascode distributed amplifier for optical communication systems

A CMOS distributed amplifier operating over 0.4-22 GHz is presented. Three stages of cascode gain cell are used in this design to enhance the gain and bandwidth performance. To improve the stability of the circuit, a damping resistor is added to the gate of the common gate amplifier in the cascode pair. Our design consumes only 8.6 mW power from a 850 mV supply voltage and this has been achieved through the use of large transistors with low current densities. The design is implemented in standard 0.13 ¿m CMOS technology. The amplifier has a unity-gain bandwidth of 22 GHz, and a maximum small signal gain of 9 dB. Input and output transmission lines are matched to 50 ¿, with the worst case return losses on the input and output of -6 dB and -8 dB, respectively. The chip area is only 750 × 1375 ¿m including all test pads and ESD protections. To the best of our knowledge this is the lowest power consumption among distributed amplifiers showing the same small signal results.