A sub-1µW, 16kHz current-mode SAR-ADC for single-neuron spike recording

This paper presents an ultra-low-power 8-bit asynchronous current-mode (CM) successive approximation (SAR) analogue-to-digital converter (ADC) for single-neuron spike recording. The novel design exploits CM techniques to support operation at supply voltages down to 1.2V, consuming under 500nA at 16kSamples/s. The design features easy scalability, and allows for a tunable sampling frequency and dynamic range (DR). The circuit is designed in a commercially-available 0.18μm CMOS technology and occupies a chip area of 0.078mm². The system requires a single, post-fabrication current calibration supported by on-chip circuitry to ensure robust operation through process and mismatch variations.