This disclosure provides systems and methods for delivering a neural stimulation pulse. A neural implant device can include an energy harvesting circuit configured to receive an input signal and generate an electrical signal based on the received input signal. A diode rectifier in series with the energy harvesting circuit can rectify the electrical signal. The energy harvesting circuit and the diode rectifier can be encapsulated within a biocompatible electrically insulating material. A neural electrode can be exposed through the biocompatible electrically insulating material. The neural electrode can be configured to deliver a neural stimulation pulse. The neural implant device can have a volume that is less than about 1.0 cubic millimeter.