The Nixel 512™ chip is composed of the Nixel Array, Analog Drive, and Digital Drive.

The Nixel Array

The Nixel Array is a 2D array of 256 neural recording elements, called nixels, which can each record from two electrodes simultaneously. Every nixel has an input switch matrix, a capacitively coupled fully-differential low-noise amplifier (LNA), an analog sample and hold (S/H) circuit, and an analog comparator.

The Analog Drive generates the required currents and voltages, as well as the static and dynamic reference and test signals used by the Nixel 512 chip. The Digital Drive generates all the control and timing signals used to configure and operate the chip using a 4-wire serial programming interface (SPI).

Electrode Input Array

The nixels are arranged in four identical panels, with each panel containing 128 electrode inputs. Each nixel is a differential amplifier connected to two electrode sites, labeled as even and odd. The bottom two rows of nixels contain reference and test electrode inputs. Pin R1 is the LFP nixel reference, pin R2 is the spike nixel reference, and pins T1 and T2 can be used for testing purposes. The four adjacent nixels [0–7] are used for LFP recording while nixels [8–127] are used for spike recording. You can program the LFP nixels and spike nixels to have independent input switch configurations, gain, high-pass and low-pass filter corner settings. All four panels can operate in parallel to record from all 512 electrodes at once. For the simplest configuration, you can connect all 16 reference and test electrode inputs together to a large reference electrode located in your active area.	‎