Dual Transimpedance Amplifier for 43 Gbps applications

A 3-stage dual TransImpedance Amplifier (TIA) on one 2x1.8 mm2 GaAs chip with 0.2 µm pHEMT technology has been designed for fiberoptic communication applications. It uses cascode connected common source FETs in a Constant-K configuration. The operating frequency ranges from DC to 35 GHz. The TIA is designed for a diode capacitance of 120 fF. The equivalent input referred noise current is around 18 pA/ÖHz for a gain of around 40 dBW or 6.5 dB. The matching at the output is better than 14 dB. Measured RF performance in combination with the small size makes it very suitable for WDM telecommunication systems. A comparison between simulations and measurements is also made