A true-time delay (TTD) cell in TSMC 0.18 μm CMOS technology for 1–5 GHz applications is presented. Process variations, ageing effects, field variations, and other non-idealities have some impacts on the TTD cell's devices. One of the vulnerable specifications of TTD cells is their delay variation. While the TTD cell works in a delay line, the cell must have a constant and robust delay in the frequency band. For this matter, the body bias technique is presented and applied to the inductor-less TTD cell. With this technique, the threshold voltage can be manipulated intentionally. So, any variation in this voltage can be compensated with the body biasing of transistors. The simulation results show the TTD cell's robust performance against non-idealities, while delay variation improves more than 3× times in the frequency band of interest. This TTD cell provides a 50.95 pS delay with only 2% variation, while S11 and S22 parameters are lower than −10 dB in the 1–5 GHz frequency band. IIP3 of the TTD cell is about 2.7 dBm, and the power consumption is 20.5 mW.
{"title":"A PVT resilient true-time delay cell","authors":"Ahmad Yarahmadi, Abumoslem Jannesari","doi":"10.1049/cds2.12143","DOIUrl":"https://doi.org/10.1049/cds2.12143","url":null,"abstract":"<p>A true-time delay (TTD) cell in TSMC 0.18 μm CMOS technology for 1–5 GHz applications is presented. Process variations, ageing effects, field variations, and other non-idealities have some impacts on the TTD cell's devices. One of the vulnerable specifications of TTD cells is their delay variation. While the TTD cell works in a delay line, the cell must have a constant and robust delay in the frequency band. For this matter, the body bias technique is presented and applied to the inductor-less TTD cell. With this technique, the threshold voltage can be manipulated intentionally. So, any variation in this voltage can be compensated with the body biasing of transistors. The simulation results show the TTD cell's robust performance against non-idealities, while delay variation improves more than 3× times in the frequency band of interest. This TTD cell provides a 50.95 pS delay with only 2% variation, while S<sub>11</sub> and S<sub>22</sub> parameters are lower than −10 dB in the 1–5 GHz frequency band. IIP3 of the TTD cell is about 2.7 dBm, and the power consumption is 20.5 mW.</p>","PeriodicalId":50386,"journal":{"name":"Iet Circuits Devices & Systems","volume":"17 2","pages":"95-110"},"PeriodicalIF":1.3,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/cds2.12143","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50146407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chua-Chin Wang, Ralph Gerard B. Sangalang, I-Ting Tseng, Yi-Jen Chiu, Yu-Cheng Lin, Oliver Lexter July A. Jose
An ultra-low-energy SRAM composed of single-ended cells is demonstrated on silicon in this investigation. More specifically, the supply voltages of cells are gated by wordline (WL) enable, and the voltage mode select (VMS) signals select one of the corresponding supply voltages. A lower voltage is selected to maintain stored bit state when cells are not accessed, lowering the standby power. And when selecting a cell (i.e. WL is enabled) to perform the read or write (R/W) operations, the normal supply voltage is used. A 1-kb SRAM prototype based on the single-ended cells with built-in self-test (BIST) and power-delay production (PDP) reduction circuits was realised on silicon using 40-nm CMOS technology. Theoretical derivations and simulations of all-PVT-corner variations are also disclosed to justify low energy performance. Physical measurements of six prototypes on silicon shows that the energy per bit is 1.0 fJ at the 10 MHz system clock.
{"title":"A 1.0 fJ energy/bit single-ended 1 kb 6T SRAM implemented using 40 nm CMOS process","authors":"Chua-Chin Wang, Ralph Gerard B. Sangalang, I-Ting Tseng, Yi-Jen Chiu, Yu-Cheng Lin, Oliver Lexter July A. Jose","doi":"10.1049/cds2.12141","DOIUrl":"https://doi.org/10.1049/cds2.12141","url":null,"abstract":"<p>An ultra-low-energy SRAM composed of single-ended cells is demonstrated on silicon in this investigation. More specifically, the supply voltages of cells are gated by wordline (WL) enable, and the voltage mode select (VMS) signals select one of the corresponding supply voltages. A lower voltage is selected to maintain stored bit state when cells are not accessed, lowering the standby power. And when selecting a cell (i.e. WL is enabled) to perform the read or write (R/W) operations, the normal supply voltage is used. A 1-kb SRAM prototype based on the single-ended cells with built-in self-test (BIST) and power-delay production (PDP) reduction circuits was realised on silicon using 40-nm CMOS technology. Theoretical derivations and simulations of all-PVT-corner variations are also disclosed to justify low energy performance. Physical measurements of six prototypes on silicon shows that the energy per bit is 1.0 fJ at the 10 MHz system clock.</p>","PeriodicalId":50386,"journal":{"name":"Iet Circuits Devices & Systems","volume":"17 2","pages":"75-87"},"PeriodicalIF":1.3,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/cds2.12141","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50146406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<p>A new method for finding closed-form time-domain solutions of linear time-invariant (LTI) systems with arbitrary periodic input signals is presented. These solutions, unlike those obtained based on the conventional Fourier-phasor method, have a finite number of terms in one period. To implement the proposed method, the following steps are carried out: (1) For a given system, represented by a transfer function, an impulse response, a block diagram etc., the governing differential equation relating the output of the system, <math>