A 3× Offset, 2.9× Power, 1.3× Sensing Time, and 4× Area Reduction Direct Input Transfer Offset Cancel DRAM IO Sense Amplifier With Static Current-Free Pre-Sensing
Do-Yoon Lim, Sehee Lim, Dong Han Ko, In-Jun Jung, Giseok Kim, D S Kim, Dong Sam Ha, Suhyun Park, Hohyun Chae, Seungjae Yei, Taehui Na, Seong‐Ook Jung
IF 5.6
IEEE Journal of Solid-State Circuits
With the increase in memory density and scaling down of the DRAM process, the length of the global IO pairs (GIO and GIOB) and the offset voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">VOS</tex-math> </inline-formula>) have increased. This degrades the power consumption and sensing time (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">tSEN</tex-math> </inline-formula>) of IO sense amplifiers (IOSAs) that sense the differential input voltage via long GIO pairs (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">ΔVGIO</tex-math> </inline-formula>). Conventional IOSAs use the self-time logic, hybrid IOSA, and GIO switches to reduce the power consumption of IOSA. However, they do not consider <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">VOS</tex-math> </inline-formula> of the IOSA, which requires a larger <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">ΔVGIO</tex-math> </inline-formula> for robust IOSA sensing operations, increasing <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">tSEN</tex-math> </inline-formula> to develop a large <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">ΔVGIO</tex-math> </inline-formula> and increasing the power consumption to pre-charge these discharged GIO pairs. To mitigate these issues, offset cancellation (OC)-IOSA has been proposed. However, since two large coupling-capacitor-based OC-IOSAs transfer <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">ΔVGIO</tex-math> </inline-formula> via capacitive coupling, it suffers from input voltage attenuation, severe area overhead, and static current. This work proposes a single capacitor-based direct input transfer static current-free pre-sensing IOSA (SCFP-IOSA) to reduce <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">VOS</tex-math> </inline-formula> and power consumption with a small area and high speed. The direct input transfer scheme is adopted in SCFP-IOSA, which removes input voltage attenuation and does not require large capacitors, thereby enhancing the sensing margin and relieving area overhead. In addition, a novel static current-free pre-sensing, which uses RC delay exponential nature, is proposed that not only pre-amplifies <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">ΔVGIO</tex-math> </inline-formula> to enhance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">VOS</tex-math> </inline-formula> tolerance but also reduces power consumption by removing static current during the pre-sense (PS) operation. The simultaneous coupling down and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">ΔVGIO</tex-math> </inline-formula> developing operation also contribute to the fast sensing operation of SCFP-IOSA. According to the measurement on the experimental chip fabricated in a 28-nm CMOS technology, SCFP-IOSA achieves three times lower <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">σVOS</tex-math> </inline-formula> of 4.42 mV, 2.9 times lower power consumption of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">2.15 μ</tex-math> </inline-formula>W, and 1.3 times faster <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">tSEN</tex-math> </inline-formula> of 3.75 ns with 4.46 times smaller area of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">10.28 μ</tex-math> </inline-formula>m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> compared with the state-of-the-art OC-IOSA.
https://doi.org/10.1109/jssc.2025.3582998
Dram
Offset (computer science)
Sense amplifier
Amplifier
Input offset voltage
Electrical engineering
Optoelectronics
Current (fluid)
Materials science
Computer science
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