Multi-Pole Bandwidth Enhancement Technique for Transimpedance Amplifiers

B. Analui and A. Hajimiri

A new technique for bandwidth enhancement of amplifiers is developed. Adding several passive networks, which can be designed independently, enables the control of transfer function and frequency response behavior. Parasitic capacitances of cascaded gain stages are isolated from each other and absorbed into passive networks. A simplified design procedure, using well-known filter component values is introduced. To demonstrate the feasibility of the method, a CMOS transimpedance amplifier is implemented in 0.18mm BiCMOS technology. It achieves 9.2GHz bandwidth in the presence of 0.5pF photo diode capacitance and a trans-resistance gain of 0.6kW, while drawing 55mA from a 2.5V supply.