The preamplifier module is a crucial element while designing dynamic latch comparators. The traditional double tail comparator utilizes a differential pair as the preamplifier stage. The circuit is generally suffered from high power dissipation and low comparison speed. This research reports the design and implementation of a low‐offset, low‐power and high‐speed dynamic latch comparator. In this work, an enhanced differential pair amplifier is employed in the preamplifier stage, to improve the power dissipation and the comparison speed of the device. A custom latch structure with rigorous transistor sizing was implemented to avoid short circuit current and mismatch in the module. The effective trans‐conductance of the cross‐coupled transistors of the latch was therefore improved for an optimal time delay solution. The equation associated with the delay was derived and the parameters that embody the speed were identified. The design has been validated by corner analysis and post‐layout simulation results in 65 nm CMOS technology process, which reveals that the proposed circuit can operate at a higher clock frequency of 20 GHz with a low‐offset of 4.45 mV and 14.28 ps propagation delay, while dissipating only 67.8 μW power consumption from 1 V supply and exhibited lowest PDP of 0.968 fJ. Moreover, the core circuit layout occupies only 183.3 μm 2 .
A simplified correlation index is proposed to be used in real-time pulse shape recognition systems. This index is similar to the classic Pearson’s correlation coefficient, but it can be efficiently implemented in FPGA devices with far fewer logic resources and excellent performance. Numerical simulations with synthetic data and comparisons with the Pearson’s correlation show the suitability of the proposed index in applications such as the discrimination and counting of pulses with a predefined shape. Superior performance is evident in signal-to-noise ratio scenarios close to unity. FPGA implementation of Person’s method and the proposed correlation index have been successfully tested and the main results are summarized.
The front-end electronics (FEE) of the Compact Muon Solenoid (CMS) is needed very low power consumption and higher readout bandwidth to match the low power requirement of its Short Strip application-specific integrated circuits (ASIC) (SSA) and to handle a large number of pileup events in the High-Luminosity Large Hadron Collider (LHC). A low-noise, wide bandwidth, and ultra-low power FEE for the pixel-strip sensor of the CMS has been designed and simulated in a 0.35 µm Complementary Metal Oxide Semiconductor (CMOS) process. The design comprises a Charge Sensitive Amplifier (CSA) and a fast Capacitor-Resistor-Resistor-Capacitor (CR-RC) pulse shaper (PS). A compact structure of the CSA circuit has been analyzed and designed for high throughput purposes. Analytical calculations were performed to achieve at least 998 MHz gain bandwidth, and then overcome pileup issue in the High-Luminosity LHC. The spice simulations prove that the circuit can achieve 88 dB dc-gain while exhibiting up to 1 GHz gain-bandwidth product (GBP). The stability of the design was guaranteed with an 82-degree phase margin while 214 ns optimal shaping time was extracted for low-power purposes. The robustness of the design against radiations was performed and the amplitude resolution of the proposed front-end was controlled at 1.87% FWHM (full width half maximum). The circuit has been designed to handle up to 280 fC input charge pulses with 2 pF maximum sensor capacitance. In good agreement with the analytical calculations, simulations outcomes were validated by post-layout simulations results, which provided a baseline gain of 546.56 mV/MeV and 920.66 mV/MeV, respectively, for the CSA and the shaping module while the ENC (Equivalent Noise Charge) of the device was controlled at 37.6 e− at 0 pF with a noise slope of 16.32 e−/pF. Moreover, the proposed circuit dissipates very low power which is only 8.72 µW from a 3.3 V supply and the compact layout occupied just 0.0205 mm2 die area.
4 March 2022 in International Journal of Circuit Theory and Applications
The treatment of inoperable cancers in the therapy terminal in Lanzhou-China, which is located at the Institute of Modern Physics (IMP), permits to work on the actual front-end readout. The availability of detailed noise spectral density characteristics for the OPA amplifier helps to develop the noise error analysis for high-resolution. This work focused on the noise model of the detector-preamplifier, which presents the low noise circuit schematic of the Transimpedance (TIA). Considering the parasitical influences, we develop a new approach to detect the weak signals based on resonant frequency, 1/√L1 (C1+CGS). In addition, the system eliminates leakage current in the reset switch and reduces the charge injection occur from the switches in the Gated Integrator (GI) and the configuration switch is made especially with two transmission gates switches, in series, with a grounded MOS switch, attached to the node between the two transmission gates switches and the linearity almost good.