A CMOS Low-Power Cross-Coupled Immittance-Converter Transimpedance Amplifier

This letter presents a low-power transimpedance amplifier (TIA) that employs an immittance converter, which provides both a negative input resistance to increase the input pole frequency and a negative inductance to improve the circuit stability. These allow for a significant bandwidth enhancement with low power consumption. Two TIAs, TIA1 with 6 GHz and TIA2 with 8.8 GHz 3 dB bandwidths, were fabricated in a standard 0.13- μm CMOS technology and were designed to operate with a 250 fF photodiode capacitance at 10 Gb/s. The transimpedance gains of the single-stage TIAs, followed by near-unity-gain output-matching buffers, are ~ 54 dBΩ, the group-delay variations and average input-referred noise currents are ±3 ps and 24 pA/√{Hz} (TIA1) and ±70 ps and 28 pA/√{Hz} (TIA2) over their 3 dB bandwidths. The TIAs occupy an active area of 250 μm× 160 μm, and without the output-matching buffer each consumes 2 mW.