A 40 GSamples/s InP-DHBT Track-and-Hold Amplifier with high dynamic range and large bandwidth

A fully differential 40 Gsample/s Track and Hold Amplifier (THA) with high dynamic range and large bandwidth is designed and fabricated in a 210 GHz-fT -InP-DHBT process. To optimize the THA performances, the THA core characteristics are extensively investigated, both by simulations and measurements. Spectral measurements performed on the THA in track mode give a THD and a SFDR of -42.5 dB and -43.8 dB, respectively, for input frequency up to 9 GHz and input voltage up to -2 dBm. This THD is equivalent to 6.7 ENOB. Time domain measurement demonstrates the THA performances for 40 GHz sampling with 2 GHz sinusoidal input signal.