This paper presents a design of a single readout front-end channel for energy spectroscopy. The front-end electronic system comprises a charge sensitive amplifier and a pulse shaping amplifier. Novel techniques based on regulated cascode circuits to increase the gain are proposed. The work addresses the design using transistors with channel length of no more than double the feature size and a supply voltage as low as 1.2 V. The analog system has been designed in a 90 nm technology and optimized to match a detector capacitance of 5 pF. Simulation results confirm the advantages of the proposed approaches in terms of gain, speed, linearity and power consumption.