In this paper, we propose a high-precision SRAM-based CIM macro that can perform 4x4-bit MAC operations and yield 9-bit signed output. The inherent discharge branches of SRAM cells are utilized to apply time-modulated MAC and 9-bit ADC readout operations on two bit-line capacitors. The same principle is used for both MAC and A-to-D conversion ensuring high linearity and thus supporting large number of analog MAC accumulations. The memory cell-embedded ADC eliminates the use of separate ADCs and enhances energy and area efficiency. Additionally, two signal margin enhancement techniques, namely the MAC-folding and boosted-clipping schemes, are proposed to further improve the CIM computation accuracy.

翻译：本文提出了一种高精度SRAM基存内计算宏单元，可执行4×4位乘法累加运算并生成9位有符号输出。利用SRAM单元固有的放电支路，在两个位线电容上实现时间调制型MAC操作与9位ADC读取功能。该原理同时适用于MAC运算与模数转换过程，确保高线性度，从而支持大规模模拟MAC累加。存储单元嵌入型ADC免除了独立ADC的使用，提升了能量效率与面积效率。此外，本文提出了两种信号裕度增强技术——MAC折叠方案与升压限幅方案，进一步提高了CIM计算精度。