Young Gon Kim

A 500 Mb/s/pin quadruple data rate SDRAM interface using a skew cancellation technique

The operating speed of microprocessors has become faster than 500 MHz, while memory access speed has not been improved accordingly in spite of quadrupled increase in the memory density every three years. This imbalance requires memory systems to use a wide data-bus and/or a high-speed I/O interface to increase access speed. Increasing access speed with a wide data-bus is studied, but is practically limited by memory pin counts. Alternatively, Rambus DRAM (RDRAM) achieves access speed up to 800 MB/s in a well-controlled printed circuit board (PCB) environment by adopting a high-speed I/O interface. Low cost systems use synchronous DRAM (SDRAM) interface because they cannot afford a high-cost PCB. This system limits memory access speed to the system clock speed, which is commonly less than 100 MHz. Double data rate (DDR) SDRAM, is twice as fast as SDRAM memory access by taking both rising and falling edges of the system clock, while keeping the SDRAM interface. To deal with clock skew, the DDR SDRAM provides an extra strobe signal for the receiving end.

MIGHTI: A high performance 16-bit DSP for mobile communication applications

This paper presents a low-power high-performance DSP processor designed for mobile communication applications. The DSP, named MIGHTI, has some special instructions that allow instruction pipelining for the compound operations. MIGHTI includes a low-power 16 K word on-chip SRAM with a flexible-port configuration, increasing memory access bandwidth substantially. It also supports a smart time-division-multiplexed DMA. With MIGHTI, the IS136 baseband function that normally requires 45MIPS from a conventional DSP, is now delivered in just 33MIPS. MIGHTI is implemented in a 3.3-volt 0.6-µm TLM CMOS technology, and operates at 40MHz. The entire DSP including the on-chip memory consumes 52.4mW.

16-bit DSP and system for baseband/voiceband processing of IS-136 cellular telephony

This paper presents 16-bit DSP processor and system for baseband and voiceband processing of IS-136 digital cellular telephony that is North America TDMA standard. The DSP, named MIGHTI, that is designed for mobile communication applications, has some special instructions that allow instruction pipelining for the compound operations. MIGHTI includes a low-power 16 K-word flexible port fullcustom memory. With MIGHTI, IS-136 baseband and voiceband processing that normally requires 45 MIPS in a conventional DSP, is performed in just 36 MIPS. The system developed for baseband and voiceband processing does meet the requirements of the IS-136 standard.