We present a 32-channel wireless implantable neural recording system-on-a-chip (SoC) that operates based on time division multiplexing (TDM) of pulse width modulated (PWM) samples with minimal substrate noise and interference. We have utilized analog-to-time conversion (ATC) on the transmitter and time-to-digital conversion (TDC) on the receiver to reduce the size and power consumption of the implantable unit by moving the digitization circuitry to the external unit. We have managed the TDM switching times such that no switching occurs during sensitive sampling onsets. The chip has been implemented in the AMI 0.5-μm standard CMOS process, occupying 3.3 × 3.0 mm2 and consuming 5.6 mW at ±1.5 V when all channels are active. The measured input referred noise for the entire system, including the receiver at 1 m distance, is only 4.9 μVrms from 1 Hz~10 kHz. Finally, in vivo testing results on rats have been presented to validate the full functionality of the system.
展开▼
机译：我们提出了一种32通道无线可植入神经片上神经记录系统（SoC），该系统基于脉宽调制（PWM）样本的时分多路复用（TDM）进行操作，并具有最小的基板噪声和干扰。我们已经利用发送器上的模数转换（ATC）和接收器上的时数转换（TDC）来通过将数字化电路移至外部单元来减小可植入单元的尺寸和功耗。我们已经管理了TDM切换时间，这样在敏感采样开始期间就不会发生切换。该芯片已采用AMI0.5-μm标准CMOS工艺实现，占用3.3×3.0 mm 2 ，当所有通道均处于活动状态时，在±1.5 V时消耗5.6 mW。整个系统（包括距离1 m处的接收器）的测量输入参考噪声在1 Hz〜10 kHz范围内仅为4.9μVrms。最后，已经提出了对大鼠的体内测试结果，以验证系统的完整功能。
展开▼
