TY - GEN
T1 - A 2pA/√Hz Current-Conveyor-Assisted Ultrasound Receiver with 25pF CMUT Parasitic Capacitance
AU - Yun, Gichan
AU - Jeong, Kyeongwon
AU - Choi, Haidam
AU - Nam, Seunghyeon
AU - Oh, Chaerin
AU - Lee, Hyunjoo Jenny
AU - Ha, Sohmyung
AU - Je, Minkyu
N1 - Publisher Copyright:
© 2023 IEEE.
PY - 2023
Y1 - 2023
N2 - Ultrasound (US) imaging has emerged as a promising solution for medical diagnosis with its low cost and biocompatibility. Recent demands for multi-dimensional imaging in medical diagnosis brought a challenge of operating multiple US transducers, especially within miniaturized probes. There have been some studies of US systems for the application of intracardiac echocardiography (ICE) [1] and transesophageal echocardiography (TEE) [2] that require highly integrated systems within miniaturized probes. The miniaturization led the capacitive micromachined ultrasonic transducer (CMUT) to be a desirable choice for its compatibility with CMOS and wide bandwidth (BW) [3]. One main characteristic of the CMUT is that it generates current signals, making a transimpedance amplifier (TIA) preferable to the low noise amplifier (LNA). However, the parasitic capacitance (mathrm{C}-{P}) at the input of the TIA highly affects the performance due to the nature of converting the input-referred voltage noise at the virtual ground to the current noise by its impedance. Therefore, power consumption should be increased with a large Cp to maintain low noise. Moreover, the input multiplexer (MUX) is often used for the US imaging system to reduce overall power consumption [4]. The input switches are implemented using bulky high-voltage MOS transistors to protect the low-voltage devices of the receiver (RX) circuit from the high-voltage pulse of the transmitter (TX) circuit. It also attributes additional Cp at the input. Note that using individual transducers for TX and RX requires a larger area. Hence, the TIA should be carefully optimized for CMUT-based US imaging systems. In this work, we present an analog front-end (AFE) assisted by a current conveyor (CC) to improve noise performance while maintaining the power consumption. The CC buffers the input current and isolates the Cp of the input from the high transimpedance gain stage, relieving the overall AFE burden.
AB - Ultrasound (US) imaging has emerged as a promising solution for medical diagnosis with its low cost and biocompatibility. Recent demands for multi-dimensional imaging in medical diagnosis brought a challenge of operating multiple US transducers, especially within miniaturized probes. There have been some studies of US systems for the application of intracardiac echocardiography (ICE) [1] and transesophageal echocardiography (TEE) [2] that require highly integrated systems within miniaturized probes. The miniaturization led the capacitive micromachined ultrasonic transducer (CMUT) to be a desirable choice for its compatibility with CMOS and wide bandwidth (BW) [3]. One main characteristic of the CMUT is that it generates current signals, making a transimpedance amplifier (TIA) preferable to the low noise amplifier (LNA). However, the parasitic capacitance (mathrm{C}-{P}) at the input of the TIA highly affects the performance due to the nature of converting the input-referred voltage noise at the virtual ground to the current noise by its impedance. Therefore, power consumption should be increased with a large Cp to maintain low noise. Moreover, the input multiplexer (MUX) is often used for the US imaging system to reduce overall power consumption [4]. The input switches are implemented using bulky high-voltage MOS transistors to protect the low-voltage devices of the receiver (RX) circuit from the high-voltage pulse of the transmitter (TX) circuit. It also attributes additional Cp at the input. Note that using individual transducers for TX and RX requires a larger area. Hence, the TIA should be carefully optimized for CMUT-based US imaging systems. In this work, we present an analog front-end (AFE) assisted by a current conveyor (CC) to improve noise performance while maintaining the power consumption. The CC buffers the input current and isolates the Cp of the input from the high transimpedance gain stage, relieving the overall AFE burden.
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U2 - 10.1109/A-SSCC58667.2023.10347934
DO - 10.1109/A-SSCC58667.2023.10347934
M3 - Conference contribution
AN - SCOPUS:85182280657
T3 - 2023 IEEE Asian Solid-State Circuits Conference, A-SSCC 2023
BT - 2023 IEEE Asian Solid-State Circuits Conference, A-SSCC 2023
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 19th IEEE Asian Solid-State Circuits Conference, A-SSCC 2023
Y2 - 5 November 2023 through 8 November 2023
ER -