Challenging MOS Amplifier

[ilovepda]

mos amplifaer

Hi All,

I've got the following specs for the design of source follower. I've been tryin it for last several days but unable to meet the specs. Please try and help with this. I'm using tsmc library

Technology Details:

Lmin = 350nm
Vdd=3.3V

Specs
Output Impedance=100Ω

Load capacitance = 500f Farads

Voltage Swing >=2.5V

Unity gain Bandwidth >= 800MHz

Small signal input is fed from a 1 farad capacitor

PS: I'm still not clear what does unity gain b/w for common drain mean as the gain is always less than unity. Please help me guys.

 

[erikl]

mos amplifier

PS: I'm still not clear what does unity gain b/w for common drain mean as the gain is always less than unity.

The gain vs. frequency curve of a common drain circuit (always a bit less than 0dB) also will somewhere start to decline with -6dB/octave (= -20dB/decade). If you prolong this decline left-upwards (i.e. to lower frequencies), its intercept point with the 0dB line is the unity gain b/w (or fT, the transit frequency) of the circuit.