High Sample-Rate Ultra-Wideband Track-and-Hold Demultiplexer (2007047)

Hittite proposes to develop a Radiation-Tolerant Ultra-Wideband Track-and-Hold (T/H) Demultiplexer to address MDA’s future needs for microwave signal sampling/data conversion. This development is motivated by the difficulties in achieving high-speed interleaved analog-to-digital converter (ADC) assemblies with good accuracy. A switched-emitter-follower T/H amplifier in the SiGe BiCMOS process with the capability for 15 GHz sampling bandwidth, 6 – 8 Gs/s sample rate, and 8 – 9 bit accuracy will be studied. This high-speed T/H will be used as the front end of a two-rank T/H sampler/demultiplexer that provides a 2:1 output sample rate reduction, enabling the use of lower rate ADCs in an interleaved assembly without the usual sample timing mismatches that degrade performance. The T/H demultiplexer can also operate as a subsampler to down convert any Nyquist bands within the 15 GHz bandwidth. This T/H circuit is expected to offer unprecedented bandwidth and operating speed while maintaining accuracy suitable for meeting the X-band and microwave data conversion goals of many military systems. Under Phase I, Hittite will perform a design study with circuit simulations to determine the feasibility and performance of the basic T/H amplifier and the two-rank demultiplexer. Prototype circuits will be built and tested in Phase II.