Ever since the introduction of high bandwidth memory (HBM DRAM) and its succeeding line-ups, HBM DRAM has been heralded as a prominent solution to tackle the memory wall problem. However, despite ...continual memory advancements the advent of high-end systems, including supercomputers, hyper-scale data centers and machine learning accelerators, are expediting requirements for higher-performance memory solutions. To accommodate the increasing system-level demands, we introduce HBM3 DRAM, which employs multiple new features and design schemes. Techniques such as an on-die ECC engine, internal NN-DFE I/O signaling, TSV auto-calibration, and layout optimization based on machine-learning algorithms are implemented to efficiently control timing skew margins and SI degradation trade-offs. Furthermore, reduced voltage swings allow for improved memory bandwidth, density, power efficiency and reliability.
There is enormous demand for high-bandwidth DRAM: in application such as HPC, graphics, high-end server and artificial intelligence. HBM DRAM was developed 1 using the advances in package technology: ...TSV, microbump and silicon-interposer. Owing to these advances, HBM has a much higher bandwidth, at a lower pin speed rate, than conventional DRAM. However, the 3D-stack structure causes TSV interface and PDN problems: TSV connection failure and 3D-accumulation of IR drop, which increases the total cost of HBM. Moreover, as memory bandwidth increases DRAM architectural challenges arise, power consumption and associated thermal problems increase as well.
DDR4 SDRAM is expected to realize low power consumption and high bandwidth using a 1.2V nominal supply voltage and to be a cost-effective solution for various applications. In this paper, bank group ...architecture, internal reference voltage level (IVREF) and pre-emphasis to overcome conventional operating frequency range are presented. CS_n to command/address latency (CAL), data bus inversion (DBI) and ×4 half-page architecture are introduced to reduce current consumption. Cyclic redundancy check (CRC) and command and address (CA) parity are adopted to check transmission errors in high bandwidth. Also, read CRC with DBI is calculated in parallel to mitigate calculation time and area penalty. Consequently, our 2Gb DDR4 SDRAM achieves 2.4Gb/s data rate at 1.0V supply voltage.
For patients who suffer from sensorineural hearing loss by damaged or loss of hair cells in the cochlea, biomimetic artificial cochleas to remedy the disadvantages of existing implant systems have ...been intensively studied. Here, a new concept of an inorganic‐based piezoelectric acoustic nanosensor (iPANS) for the purpose of a biomimetic artificial hair cell to mimic the functions of the original human hair cells is introduced. A trapezoidal silicone‐based membrane (SM) mimics the function of the natural basilar membrane for frequency selectivity, and a flexible iPANS is fabricated on the SM utilizing a laser lift‐off technology to overcome the brittle characteristics of inorganic piezoelectric materials. The vibration amplitude vs piezoelectric sensing signals are theoretically examined based on the experimental conditions by finite element analysis. The SM is successful at separating the audible frequency range of incoming sound, vibrating distinctively according to varying locations of different sound frequencies, thus allowing iPANS to convert tiny vibration displacement of ≈15 nm into an electrical sensing output of ≈55 μV, which is close to the simulation results presented. This conceptual iPANS of flexible inorganic piezoelectric materials sheds light on the new fields of nature‐inspired biomimetic systems using inherently high piezoelectric charge constants.
The new concept of a biomimetic artificial hair cell using a flexible inorganic piezoelectric acoustic nanosensor (iPANS) is presented. A highly sensitive flexible piezoelectric sensor that responds to sound‐driven vibrations of a thin silicone membrane is fabricated using a laser lift‐off process. The iPANS shows remarkable capability to sense tiny vibrations caused by an external sound wave.
In this research, we have developed a multi-channel piezoelectric acoustic sensor (McPAS) that mimics the function of the natural basilar membrane capable of separating incoming acoustic signals ...mechanically by their frequency and generating corresponding electrical signals. The McPAS operates without an external energy source and signal processing unit with a vibrating piezoelectric thin film membrane. The shape of the vibrating membrane was chosen to be trapezoidal such that different locations of membrane have different local resonance frequencies. The length of the membrane is 28 mm and the width of the membrane varies from 1 mm to 8 mm. Multiphysics finite element analysis (FEA) was carried out to predict and design the mechanical behaviors and piezoelectric response of the McPAS model. The designed McPAS was fabricated with a MEMS fabrication process based on the simulated results. The fabricated device was tested with a mouth simulator to measure its mechanical and piezoelectrical frequency response with a laser Doppler vibrometer and acoustic signal analyzer. The experimental results show that the as fabricated McPAS can successfully separate incoming acoustic signals within the 2.5 kHz-13.5 kHz range and the maximum electrical signal output upon acoustic signal input of 94 dBSPL was 6.33 mVpp. The performance of the fabricated McPAS coincided well with the designed parameters.
This paper presents the development of a piezoelectric artificial cochlea (PAC) device capable of analyzing vibratory signal inputs and converting them into electrical signal outputs without an ...external power source by mimicking the function of human cochlea within an audible frequency range. The PAC consists of an artificial basilar membrane (ABM) part and an implantable packaged part. The packaged part provides a liquid environment through which incoming vibrations are transmitted to the membrane part. The membrane part responds to the transmitted signal, and the local area of the ABM part vibrates differently depending on its local resonant frequency. The membrane was designed to have a logarithmically varying width from 0.97 mm to 8.0 mm along the 28 mm length. By incorporating a micro-actuator in an experimental platform for the package part that mimics the function of a stapes bone in the middle ear, we created a similar experimental environment to cochlea where the human basilar membrane vibrates. The mechanical and electrical responses of fabricated PAC were measured with a laser Doppler vibrometer and a data acquisition system, and were compared with simulation results. Finally, the fabricated PAC in a biocompatible package was developed and its mechanical and electrical characteristics were measured. The experimental results shows successful frequency separation of incoming mechanical signal from micro-actuator into frequency bandwidth within the 0.4 kHz-5 kHz range.
Cochlear implants (CIs) have become the standard treatment for severe-to-profound sensorineural hearing loss. Conventional CIs have some challenges, such as the use of extracorporeal devices, and ...high power consumption for frequency analysis. To overcome these, artificial basilar membranes (ABMs) made of piezoelectric materials have been studied. This study aimed to verify the conceptual idea of a totally implantable ABM system. A prototype of the totally implantable system composed of the ABM developed in previous research, an electronic module (EM) for the amplification of electrical output from the ABM, and electrode was developed. We investigated the feasibility of the ABM system and obtained meaningful auditory brainstem responses of deafened guinea pigs by implanting the electrode of the ABM system. Also, an optimal method of coupling the ABM system to the human ossicle for transducing sound waves into electrical signals using the middle ear vibration was studied and the electrical signal output according to the sound stimuli was measured successfully. Although the overall power output from the ABM system is still less than the conventional CIs and further improvements to the ABM system are needed, we found a possibility of the developed ABM system as a totally implantable CIs in the future.
This paper presents the fabrication of Si
3
N
4
-based artificial basilar membrane (ABM) with ZnO nanopillar array. Structure of ABMs is composed of the logarithmically varying membrane fabricated by ...MEMS process and piezonanopillar array grown on the Si
3
N
4
-based membrane by hydrothermal method. We fabricate the bottom substrate containing Si
3
N
4
-based membrane for inducing the resonant motions from the sound wave and the top substrates of electrodes for acquiring electric signals. In addition, the bonding process of the top and bottom substrate is performed to build ABM device. Depending on sound wave input of the specific frequency, specific location of the ABM produces a resonant behavior. Then a local deformation of the piezonanopillar array produces an electric signal between top and bottom electrode. As experimental results of the fabricated ABM, the measured resonant frequencies are 2.34 kHz, 3.97 kHz, and 8.80 kHz and the produced electrical voltages on each resonant frequency are 794 nV, 398 nV, and 89 nV. Thus, this fabricated ABM device shows the possibility of being a biomimetic acoustic device.
This paper presents the fabrication of Si3N4-based artificial basilar membrane (ABM) with ZnO nanopillar array. Structure of ABMs is composed of the logarithmically varying membrane fabricated by ...MEMS process and piezonanopillar array grown on the Si3N4-based membrane by hydrothermal method. We fabricate the bottom substrate containing Si3N4-based membrane for inducing the resonant motions from the sound wave and the top substrates of electrodes for acquiring electric signals. In addition, the bonding process of the top and bottom substrate is performed to build ABM device. Depending on sound wave input of the specific frequency, specific location of the ABM produces a resonant behavior. Then a local deformation of the piezonanopillar array produces an electric signal between top and bottom electrode. As experimental results of the fabricated ABM, the measured resonant frequencies are 2.34 kHz, 3.97 kHz, and 8.80 kHz and the produced electrical voltages on each resonant frequency are 794 nV, 398 nV, and 89 nV. Thus, this fabricated ABM device shows the possibility of being a biomimetic acoustic device.
PDF
