A multi-standard wireless devices are now highly demanded. To realize the multi-standard receivers, a wideband low noise amplifier is an essential. However, the traditional narrow band LNA design techniques are not suitable for wideband LNA design. The narrow band LNAs are using inductor at load to create a resonance at a certain frequency to get a gain. Also, the narrow band LNAs are using inductors and capacitors for a input matching at a certain point. However, the wideband LNA must have wide gain and wide input matching. So, narrow band design techniques can not be used in wideband LNA design.
There are some design techniques for wideband LNA. The techniques are distributed amplifier, multi-section reactive network at the input, common gate at the input, and resistive feedback.
The distributed amplifier uses many amplifiers to get wide input and gain range. However, it needs large power consumption and large chip area. The multi-section reactive network uses band-pass circuit at the input to get wide input matching. It gives good input matching for wideband. Also, it consumes lower power than distributed case. However, it needs many inductors for band pass matching network which increases chip area. Also, the loss of band pass network is added to the total noise figure of LNA. The common gate can be uses as a input stage for good input matching 1/gm. However, it has low gain. So common gate LNA needs a additional gain stages. Also, normally, the common gate topology gives high noise characteristic than common source topology. The resistive feedback uses feedback structure to get wide input matching. Compare the other techniques, the resistive feedback structure can have smaller number of inductors which increase the chip area. So, the resistive feedback topology can reduce the chip area. The proposed LNA uses resistive feedback techniques for small chip are and acceptable gain.
The proposed LNA uses inverter is used as gm stage to increase the transco...