Ultra low noise 2.5 Gbit/s 3.3V transimpedance amplifier with automatic gain control

We present a high performance 2.5 Gb/s Transimpedance Amplifier (TIA) with the lowest input noise current ever reported at 3.3 V. Typical use is as a low noise preamplifier for lightwave receiver modules in optical fiber with an exceptionally good sensitivity and high gain. The circuit features a very small chip size, differential outputs, very low power consumption and built in Automatic Gain Control (AGC) to allow operation over a wide dynamic range. We have used an advanced enhancement-depletion mode PHEMT process to fabricate the device. This type of process offers the designer the flexibility and options required to obtain both a very good noise figure and low power consumption.