A multichannel analyzer (MCA) for gamma ray spectroscopy is presented. The system comprises a silicon photomultiplier, an analog front-end readout IC, a piecewise-linear ADC, and a digital back-end. The AFE and the PWL-ADC were fabricated in a 180nm CMOS process. A highly programmable architecture allows pulse-height analysis with reconfigurable resolution across the full dynamic range which enables variable energy bin-width in specific regions of interest with a smaller digital word length. This allows the implementation of a DBE with fewer resources, and optimal energy binning within a spectrum. The FPGA-based DBE performs histogramming for spectrum analysis. Measured peaks from 32keV to 1.33MeV and reconfigurable energy bin-widths of 3keV to 58keV show the versatility of the proposed MCA.