Wideband Trans-Impedance Amplifier

Designed a multi-stage wideband transimpedance amplifier in 45nm CMOS using Cadence, achieving:

507 kΩ transimpedance gain
359 MHz bandwidth
120.9 nA rms input-referred noise

All specs met or exceeded on a 1V supply.

Architecture

A 4-stage pipeline: common-gate input stage, differential pair, cascaded common-source amplifiers, and a common-drain output buffer. The stack was architected to simultaneously satisfy three competing constraints: low input impedance (to absorb photodiode current without loading it), high overall gain, and a 600Ω differential load drive requirement — the kind of tradeoff where fixing one stage’s spec tends to break another’s.

Notes

Add schematics, gain/phase plots, or noise simulation screenshots here once exported from Cadence.