A 400-Mbps 1.05 pJ/Bit IR-UWB Transmitter for High-Density Neural Recording Systems

This brief presents an impulse radio ultra-wideband (IR-UWB) transmitter (TX) designed for miniature multi-channel neural recording platforms in freely moving laboratory animals. We introduce a 5-bit data-to-time modulation technique utilizing a 5-cell capacitive array. This approach minimizes the data rate’s dependency on pulse repetition frequency, while significantly reducing power dissipation and simplifying the TX’s architecture. Measurement results with the TX fabricated in TSMC 65-nm standard CMOS technology show that the proposed circuit provides a linear time change in the pulsewidth with a time step of 84 ps in average for every least significant bit in the input. Furthermore, the entire circuit consumes only $422~{\mu }$ W from a 0.65-V supply. The proposed TX achieves a significantly low energy consumption of 1.05 pJ/bit at 400 Mbps in a 0.5-m transmission range. The fabricated circuit occupies 0.255 mm2 of die area including pads.