A 28nm Integrated True Random Number Generator Harvesting Entropy from MRAM
This paper presents an integrated True Random Number Generator (TRNG) based on the random switching behavior of Magnetic Tunnel Junctions (MTJs) under low write current. A complete TRNG is designed with minimal overhead to an existing embedded MRAM in 28nm CMOS. To the best of our knowledge, this is the first experimental study of this random process and the first TRNG implemented with commercial STT-MRAM technology. The prototype adds only 180μm 2 to a standard MRAM array for TRNG operation. It passes all NIST randomness tests across -25 to 100°C, while consuming 18pJ/bit with 66Mbps throughput at the nominal condition. authors: Kaiyuan Yang, Qing Dong, Zhehong Wang, Yi-Chun Shih, Yu-Der Chih, Jonathan Chang, David Blaauw, Dennis Svlvester
Memory
Memory
Data is the most valuable resource in today’s digital economy. Currently over 2.5 quintillion (1018) bytes of data are generated daily and the pace is accelerating. More data than ever needs to be processed. Memory plays a key role in the flow of data. The gap between logic and memory is a bottle neck to system performance. To optimize the trade-off between cost and performance, a hierarchical memory system has been adopted. At the top of the hierarchy are static random access memories (SRAM) and dynamic random access memory (DRAM), both inherently volatile. SRAM is integrated right on the logic chips as cache memory to provide fastest access. DRAM is physically smaller than SRAM and consequently supports higher capacity. DRAM is generally an off-chip memory solution and ~10x slower than SRAM due to the need for constant refresh. Non-volatile memories (NVM) such as Flash are next in the hierarchy providing much higher memory capacity and density while also preserving information in the absence of power.
Recent new technologies are emerging rapidly to bring processing tasks near to or inside the memory to improve computing efficiency and enable new functionalities. Emerging NVMs use new types of materials and mechanisms to store data. They are promising for blending the memory hierarchy to boost the overall performance. Furthermore, their unique characteristics offer great potential to enable new applications (e.g. neuromorphic computing) and novel architectures (e.g. 3D integration).
TSMC’s non-volatile memory solutions include Flash, Spin-transfer torque magnetic random access memory (STT-MRAM), and resistive random access memory (RRAM). TSMC is also actively exploring phase change random access memory (PCRAM), and spin-orbit torque MRAM (SOT-MRAM) elements, as well as selector devices which are essential to support higher density cross-point array architectures.
