FlexSpIM: An Event-Based Digital Compute-In-Memory Accelerator with Flexible Operand Resolution and Layer-Wise Hybrid Stationarity
By Nicolas Chauvaux, Adrian Kneip and Charlotte Frenkel
Delft University of Technology (TU Delft), Delft, The Netherlands

Abstract
Compute-in-memory (CIM) accelerators for spiking neural networks (SNNs) offer a promising solution for achieving μs-level inference latency and ultra-low energy in edge vision applications. However, their limited flexibility at both circuit and system levels restricts their deployment across diverse workloads. This work introduces FlexSpIM, a digital CIM architecture supporting arbitrary operand resolution and shape within a unified storage for weights and neuron states (i.e., membrane potentials). These circuit-level capabilities enable a layer-level hybrid weight- and output-stationary dataflow, maximizing operand reuse and reducing costly on- and off-chip data movement during SNN execution. Measurement results from a fabricated FlexSpIM prototype in 40-nm CMOS demonstrate competitive 1-bit-normalized energy efficiency and higher throughput compared with prior fixed-precision digital CIM-based SNN accelerators, while providing bitwise resolution reconfiguration. Evaluated on the IBM DVS gesture dataset, FlexSpIM achieves 95.8% accuracy while enabling up to 45% energy and 52% latency reductions in large-scale systems compared with fixed stationarity approaches.
Index Terms—Digital compute-in-memory, spiking neural net works, flexible operand resolution, hybrid-stationary dataflow.
To read the full article, click here
Related Semiconductor IP
- Root-of-Trust IP - High-Assurance Security for Advanced and Regulated Applications
- Root-of-Trust IP - Enhanced-Assurance, Configurable Security for Scalable Semiconductor Designs
- Root-of-Trust IP - Compact, Configurable Security for Flexible Semiconductor Designs
- 100-10Gbps Ethernet MAC Controller
- SD Card Controller
Related Articles
- Peregrino: A Full-Hardware Accelerator for the Complete Falcon Post-Quantum Digital Signature Scheme on Resource-Constrained Edge Devices
- Assessing Design Space for the Device-Circuit Codesign of Nonvolatile Memory-Based Compute-in-Memory Accelerators
- 3+ ways to design reconfigurable algorithm accelerator in IP block
- RAID6 accelerator in a PowerPC IOP SOC
Latest Articles
- LLM Agent-Based Design of RISC-V CPUs with FPGA-in-the-Loop Evaluation
- Automated Multi-Line Bug Repair Using Model Checker Aided LLMs: A Case Study on RISC-V Processors
- Cryogenic Recharacterization of a Commercial 22 nm FD-SOI Foundry Standard-Cell Library
- A 105 MS/s 4.18 nJ/inference 0.765 mm² Mixed-Signal Streaming ML Engine for Wireless Baseband in 12LP+ FinFET
- Agentic AI for Heterogeneous System Design Across Chip, Scale-Up, and Scale-Out Domains