A ferroelectric RAM, especially Chain FeRAM™ , can boost the performance of memory systems such as HDD and SSD. Chain FeRAM can be used as a non-volatile RAM cache in these memory systems, improving effective write bandwidth by minimizing the frequency of seeks to disk  and program/erase access to NAND flash memory . A 128Mb Chain FeRAM with DDR2 interface has been previously developed . However, the memory systems require further improvement to reach memory capacity of 256Mb while operating with a lower voltage of 1.3V to meet DDR3/LPDDR2 interface requirements and to accommodate device scaling. We demonstrate a ferroelectric capacitor overdrive technique with shield bitline drive. This technique applies a larger bias to the ferroelectric capacitor in a read operation, resulting in a larger readout cell signal in low-voltage operation.