DAQ Chip (Neural Recording ASIC)
A DAQ chip is the application-specific integrated circuit inside a headstage or probe that amplifies, band-pass filters and digitizes a block of electrode channels on one low-power die; the chip sets the channel count, the noise floor, the sampling rate and whether the system can stimulate.
The headstage, the cable and the data acquisition system are built around the chip's digital output, so a recording system is specified by its chip first.
NeuroNexus headstages use the Intan RHD series for recording — RHD2216 at 16 channels, RHD2132 at 32, RHD2164 at 64 — and the RHS2116 for recording and stimulation, which adds a current stimulator on each channel and requires the supply voltages and control lines that an XDAQ provides in record-and-stimulate mode. All sample at 16 bits and up to 30 kS/s per channel, with an input-referred noise near 2.4 µV rms and a pass-band set in software. Two other chip families enter the catalog on the probe rather than in the headstage: the Neuropixels ASIC, 384 recording channels on the probe base, acquired through an X-Series NP headstage into XDAQ; and the SiNAPS chip, which places an active pixel under each of 256 or 1,024 sites on the shank, samples at 12 bits and 20 kS/s, and streams through the SiNAPS interface box to Smartbox.
The chip is where recording systems are compared. Noise floor, resolution, channels per die, power and the presence of a stimulator are properties of the chip; the headstage packages one or two chips, and the data acquisition system acquires their streams. The Neural Recording Chips guide compares the chips in full.
Typical values
| Intan RHD2216 / RHD2132 / RHD2164 | 16 / 32 / 64 channels, record |
|---|---|
| Intan RHS2116 | 16 channels, record and stimulate |
| Neuropixels ASIC | 384 recording channels on the probe |
| SiNAPS chip | 256 or 1,024 active pixels on the shank; 12-bit, 20 kS/s, 6.5 µV rms |
| RHD performance | 16-bit, up to 30 kS/s, about 2.4 µV rms |