A 1-Mbit BiCMOS DRAM using Temperature Compensation Circuit Techniques

Abstract

A temperature-compensation circuit technique for a dynamic random-access memory (DRAM) with an on-chip voltage limiter is evaluated using a 1-Mb BiCMOS DRAM. It was found that a BiCMOS bandgap reference generator scheme yields an internal voltage immune from temperature and V/sub cc/ variation. Also, bipolar-transistor-oriented memory circuits, such as a static BiCMOS word driver, improve delay time at high temperatures. Furthermore, the BiCMOS driver proves to have better temperature characteristics than the CMOS driver. Finally, a 1-Mb BiCMOS DRAM using the proposed technique was found to have better temperature characteristics than the 1-Mb CMOS DRAM which uses similar techniques, as was expected. Thus, BiCMOS DRAMs have improved access time at high temperatures compared with CMOS DRAMs. >