Dong-Il Seo

A 1.8-V 128-Mb mobile DRAM with double boosting pump, hybrid current sense amplifier, and dual-referenced adjustment scheme for temperature sensor

To verify three important circuit schemes suitable for DRAMs in mobile applications, a 1.8-V 128-Mb SDRAM was implemented with a 0.15-/spl mu/m technology. To achieve an ideal 33% efficiency, the double boosting pump uses two capacitors series connection at pumping phase, while they are precharged in parallel. The hybrid folded current sense amplifier together with a novel replica inverter connection improved power and speed performances. Also, a dual-referenced adjustment scheme for a temperature sensor was proposed to allow a very high accuracy in tuning. Without loss in productivity, the implemented dual-referenced searching technique achieved tuning error of less than /spl plusmn/2.5/spl deg/C.

Wordline coupling noise reduction techniques for scaled DRAMs

The wordline architecture of the twisted word line (TWL) scheme and a wordline latch circuit for suppressing wordline coupling noise have been proposed and demonstrated. Using this approach, wordline coupling noise is reduced by 70% compared to the conventional wordline structure. This technique was found to be effective for suppressing wordline coupling noise with minimum layout penalty in scaled high-density DRAMs

Double boosting pump, hybrid current sense amplifier, and binary weighted temperature sensor adjustment schemes for 1.8V 128Mb mobile DRAMs

A 1.8V 128Mb SDRAM is implemented for low current mobile applications with a 0.15/spl mu/m technology. The double boosting pump and hybrid current sense amplifier schemes are optimized for the low voltage regime with high pumping efficiency and stable I-to-V gain, respectively. A temperature sensor together with the binary weighted adjustment technique allow a very accurate implementation without loss in productivity.

Charge-transferred presensing and efficiently precharged negative word-line schemes for low-voltage DRAMs

A 256 Mb SDRAM is implemented with a 0.12 /spl mu/m technology to verify two circuit schemes suitable for mobile application. A charge transferred presensing is proposed to achieve fast low-voltage sensing and robust operation. With a precharge disabler for productivity, new negative word-line scheme is also proposed to bypass the majority of discharging current to VSS without switching control.