A second-generation monolithic silicon radiation sensor has been built and characterized. This pixel detector has CMOS circuitry fabricated directly in the high-resistivity float-zone substrate. The bulk is fully depleted from bias applied to the backside diode. Within the array, PMOS pixel circuitry forms the first stage amplifiers. Full CMOS circuitry implementing further amplification as well as column and row logic is located in the periphery of the pixel array. This allows a sparse-field readout scheme where only pixels with signals above a certain threshold are readout. We describe the fabrication process, circuit design, system performance, and results of gamma-ray radiation tests. Show Partial Abstract