Most concepts for retinal stimulation rely on rectangular waveforms, although studies suggest sinusoidal stimulation might improve visual perception. We present a novel approach for a power and area efficient generation of sinusoidal stimulation waveforms by modulation of an external reference sine wave. Modulation is performed by an attenuator based on variable CMOS pseudo-resistors. The implementation of a complete channel is presented along with two different versions of the attenuators. Both architectures are investigated in terms of signal quality, symmetry and power consumption.