Search for a command to run...
Existing Amplifier-Shaper-Discriminator (ASD) ASICs, fabricated in 500 nm and 130 nm CMOS technologies, suffer from high power consumption, large area, and limited scalability, making them unsuitable for future high-density detector systems requiring greater efficiency. These limitations highlight the need for a more scalable, low-power solution. This paper presents the design and electrical characterization of a novel four-channel Analog Front-End (AFE) for the ATLAS Muon Drift Tube (MDT) Detectors, implemented in 65 nm CMOS. The channel architecture is optimized to reduce power and area compared to previous designs, without sacrificing key metrics such as signal integrity, peaking time, and dynamic range. Each channel comprises a Charge-Sensitive Preamplifier (CSP), Shaper, and Discriminator. The CSP achieves a 15 ns peaking time even with large parasitic capacitance (e.g., 60 pF ), which is typically challenging for high-speed circuits. The Shaper uses a dual Active-RC stage for unipolar-to-bipolar conversion, enabling fast baseline restoration, better pile-up rejection, and improved timing. Baseline recovery time is 320 ns for high input charges, decreasing with lower charges. The analog signal entering the Discriminator has a sensitivity of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$8 \text{mV} / \text{fC}$</tex> and a linear response up to 800 mV -peak for input charges from 5 fC to 100 fC . The system operates in Time-over-Threshold (ToT) mode: the rising edge marks arrival time, while pulse width encodes the amount of charge detected. Over the entire input charge range, the ToT pulse exhibits a dynamic variation of 26 ns , providing high precision for timing measurements. Each channel occupies <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.235 \text{mm}^{2}$</tex>, consumes 10.6 mA from a 1.2 V supply, and shows excellent scalability, making it a strong candidate for ATLAS MDT front-end upgrades in the HighLuminosity LHC (HL-LHC).