U-Sonic: An Open-Source 8-Channel Ultrasound Transmit IP in a 130 nm RISC-V SoC

By Federico Villani ¹, Nico Canzani ¹, Marc-André Wessner ¹, Philippe Sauter ¹, Enrico Zelioli ¹, Andrea Cossettini ¹, Christoph Leitner ¹, Luca Benini ^1,2
1 ETH Zurich, Switzerland
² University of Bologna, Italy

Abstract

Miniaturized ultrasound (US) probes require programmable and synchronized transmit (TX) excitation across multiple elements, while existing compact platforms often rely on limited microcontroller (MCU) pulse generators or closed-source fixed-function pulser devices. We present U-Sonic, an open-source digital US TX peripheral integrated into a 32-bit RISC-V system-on-chip (SoC). The implemented SoC integrates 8 pulser cores, while the parameterized architecture supports up to 16 channels. Each core generates single- or dual-tone bursts with programmable period, duty cycle, pulse count, polarity, and idle level, together with optional inverted stop pulses for active damping. A shared memory-mapped Open Bus Interface (OBI) enables synchronous start and stop of arbitrary channel subsets and supports composite bipolar, gated, and three-level excitation schemes. Functional correctness was verified in Verilator against a Python golden model over 4379 checked cycles across directed and randomized configurations, and confirmed on a Terasic DE10-Lite field-programmable gate array (FPGA). The design was synthesized and placed-and-routed in IHP 130 nm. The post-layout area in kilo gate equivalents (kGE), scales as 1.65 kGE plus 1.66 kGE per channel. The 8-channel instance occupies 14.9 kGE, corresponding to approximately 14.3% of the 104 kGE SoC. The register-transfer level (RTL), register descriptions, verification collateral, and software support are released as open source.

Index Terms—Ultrasound transmit, pulser, open-source hard ware, RISC-V, system-on-chip, multi-element, 130 nm CMOS

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