The Stim Engines NNC6521 is a programmable stimulation IC integrating an SPI interface, battery charging circuitry, power switches, and a high-performance stimulation module. Designed to operate with minimal external components, the NNC6521 offers a compact solution for a wide range of applications. The chip features two channels (four electrodes) with current drivers capable of delivering both anodic and cathodic stimulation currents, with peak currents of up to 100 mA. Through its SPI interface, the NNC6521 supports the generation of arbitrary current waveforms, making it suitable for a broad range of electrical stimulation applications.