A neural recorder IC with HV input multiplexer for voltage and current stimulation with 18V compliance

Abstract

This paper presents an innovative ASIC design used in a high voltage (HV) neuromodulation system-in-package (SiP). A HV input switching network offers synchronous neural recording at 32 electrodes and independent stimulation on two selectable electrodes with up to 15mA and 18V input compliance. In addition, it provides artifact canceling and enables the use of different supply voltages for stimulator and recorder. Thus, a HV stimulator can be combined with a high efficient LV neural recorder design. Frequency separation of the local field potentials (LFP) and action potentials (AP) with individually adjustable gain and frequency settings via switched capacitor filter structures implicitly improves the input referred quantization error. The LFP low corner frequency can be measured reproducibly at 60mHz and the measured input referred noise is 3.3 μVrms for both, the AP and LFP band. The design is implemented in a 180nm HV CMOS technology, has a die size of 3.8mm × 4.3mm and a power consumption of 4.5mW.