A MIXED-MODE VOLTAGE DOWN-CONVERTER WITH IMPEDANCE ADJUSTMENT CIRCUITRY FOR LOW-VOLTAGE HIGH-FREQUENCY MEMORIES

This paper proposes a low voltage operation technique for a voltage do wn converter (VDC) using a mixed-mode VDC (MM-VDC), that combines an a nalog VDC and a digital VDC, and provides high frequency application u sing an impedance adjustment circuitry (IAC), The MM-VDC operates with a small response delay and a large supply current. Moreover, the IAC is adopted to the MM-VDC for wide range frequency operation under low voltage conditions. The IAC can change the supply current capability i n accordance with the load operation frequency to avoid the overshoot and undershoot problems caused by the unmatched supply current, A 64 M b-DRAM test device operated with the MM-VDC achieves well-controlled i nternal voltage (VCI) level and achieves high frequency operation, The se systems, the MM-VDC and the IL-VDC, can be applicable for both low voltage and high frequency operation.