A 167-MHz 1-Mbit CMOS synchronous cache SRAM was developed using 0.40-µm process technology. The floor plan was designed so that the address registers are located in the center of the chip, and high-speed circuits were developed such as the quasi latch (QL) sense amplifier and the one-shot control (OSC) output register. To maintain suitable setup and hold time margins, an equivalent margin (EM) design method was developed. 167-MHz operation was measured at a supply voltage of 2.5 V and an ambient temperature of 75. The same margins 1.1 ns of the setup time and hold time were measured for the specifications of a setup time of 2.0 ns and a hold time of 0.5 ns.

A low-voltage, high-speed 4-bit CMOS single chip microprocessor, with instruction execution time of 1.0µs at a power supply voltage of 1.8V, has been developed. A single chip processor generally includes crystal oscillation circuits to generate a system clock or a time-base clock. But when the operating voltage is lowered, it becomes difficult to get oscillations to start reliably and to continue stably. This paper describes a low voltage circuit design method for built-in crystal oscillators. Simple design equations for oscillation starting voltage and oscillation starting time are introduced. Then effects of the circuit device parameters, such as power supply voltage, loop gain values, and subthreshold swing S, on the low voltage performance of the crystal oscillators are considered. It is shown that the crystal oscillators operate in a tailing (subthreshold) region at voltages lower than about 1.8 V. Subthreshold swing, threshold voltage, and open loop gain have a significant influence on low voltage oscillation capability. This design method can be applied to crystal oscillators for a wide range of operating voltages.

A 0.5 µm CMOS embedded function type gate array family with high speed modules was developed. This family has: an effective basic cell; high speed, compiled type metallized and diffused RAMs; PLL (Phase Locked Loop); and GTL (Gunning Transceiver Logic) to realize operation of over 100 MHz at 3.3 V. This paper describes the basic cell architecture and the compiled type metallized RAM. A divided MOS transistor type basic cell is effective for metallized modules such as metallized RAM and internal logic circuits. The appropriate basic cell size (height) can be decided from the viewpoints of the relationship between the number of usable basic cells and the basic cell height, and the logic circuit speed. Propagation delay time of the 2-input NAND is 200 ps at a standard load of fan out=2 and metal length=1.4 mm. For the universal ASIC, the compiled RAM is indispensable. Single port and multi-port metallized RAMs which are structured by using the basic cells are discussed. The new single port memory cell circuit which has a differential write and single end read operating method is introduced. This memory cell circuit can be realized using one basic cell. The diffused layer region of the NMOS transfer gates for the read operation is shared between neighbor memory cells. So, the capacitance of the bit line becomes smaller, and a high speed access time can be achieved. The measured access time of 1 kbits is 4.2 ns. The new multi-port memory cell circuits which have a single end write and single end read operating method are introduced. The read operating method is the same as that of the single port memory cell circuit. The access time shows very high speed operation comparable to that of the single port memory. This 3F (Flexible, Fast, and Friendly) ASIC family can be applied to high speed processors in workstations and graphics equipment.

A mixed BiCMOS/CMOS channelless gate array family with 3-metal-layer wiring using a 5 V version, 0.5 µm BiCMOS technology is discussed. The speed and power performance of CMOS gates are superior to those of BiCMOS gates for light load capacitance. The power-delay product of CMOS gates at light load is 50% less than that of BiCMOS gates. Therefore, by using CMOS and BiCMOS gates selectively according to the weight of the capacitance load, the performance of the BiCMOS gate array is enhanced. Then, a new mixed BiCMOS/CMOS basic cell structure which can be used as BiCMOS or CMOS gates, which go to the wiring channels, was developed. The area efficiency of the developed basic cell is 16% better than that of the conventional basic cell, as got from design automation experience, etc. The wiring method of the power supply reinforcement lines of the third metal layer in a large chip was examined from the viewpoint of the number of useful basic cells. As a result, by locating the reinforcement lines at every basic cell, the number of useful basic cells is about 14% more than that of another method in which the reinforcement lines are located at certain intervals of basic cells. Propagation delay time of the 2-input NAND is 190 ps at fan out 10 load. Under a light load, a pure CMOS NAND is faster, achieving a 140 ps gate delay at fan out 2 load. This gate array family can be applied to high speed processors.