NVIDIA's 32 Gb/s optical receiver reaches -18.5 dBm sensitivity at 0.416 pJ/b with an almost free trick: reusing the rail-to-rail TIA output as a noise-free DFE decision, trading under 1 mA for 2 dB of sensitivity. Why receiver sensitivity is the best investment in the whole optical link — explained figure by figure.

Direct-detection optical receivers normally use only one terminal of the PD. NVIDIA recovers the wasted cathode current to build a differential TIA, improving sensitivity by roughly √2. The TIA doubles, but laser power across the whole link drops. A figure-by-figure walkthrough of VLSI 2026 C20.2.