Viewing posts from March, 2025
In a previous article, we described an ultralow cost time-domain reflectometer (TDR) with 150-ps edges, which is used in fuel gauges for heavy equipment, basically a radar dipstick. For that job, moderate performance was OK, and somebody else was doing most of the system. Our bit was all analog and pretty minimalist—a single-diode sampler, silicon-germanium BJT edge generators, two-stage BJT amplifier, and JFET track/hold. Its rock-bottom BOM cost ($1.30 @ 100 pcs) made it possible for the whole gauge to sell for under $40. That performance is far from the limit for low-cost samplers, as we'll see.