A high speed 16 kbit ECL RAM
A 16384 /spl times/ 1 bit ECL RAM (emitter coupled logic random access memory) with an access time of 15 ns and a power dissipation of 700 mW has been developed. The high packing density and performance were achieved by using a p-n-p load cell, a novel ECL circuit, and U-groove isolation. The test results proved that a p-n-p load cell is very effective in producing a fast high-density bipolar RAM having a capacity of over 64 Kbits.
A 3.5ns 4Kb ECL RAM
by connecting 1/0 (Input/Output) terminals of smaller RAM devices with x 4b arrangements, with board wiring which increases 1/0 capacitance. The switching speed decreases by the additional 1/0 capacitance; approximately 20pslpF for ECL. A two metal layer has been used in ECL RAM, allowing flexibility within a system; e.g., 256Word x 16b, 512Word x 8b, arrangement, etc. Since the 1/0 capacitance is designed to be independent of any arrangement, a switching speed improvement is possible. The block diagram of the RAM shown in Figure 2 consists of 4-planes of 256W x 4b memory arrays. An emitter follower circuit for each input is used to drive several internal circuits so that the input capacitance is determined by the small input capacitance of the emitter follower circuit. In the output circuit, a collector dotting is used in the sense amplifier circuit; Figure 2. As a result, there is a low I/O capacitance independent of any organization.
High Speed Bipolar ICs Using Super Self-Aligned Process Technology
We have developed a new bipolar process technology, called SST. The emitter region, base p region, base p+ region, base p+ polysilicon electrode and emitter contact window of NPN transistor are formed by one mask photolithography process. The transistor active regions are all self-aligned. Therefore, small-size transistors can be realized and high performance is achieved by the decreased collector-base junction capacitance. A new bipolar integrated circuit using SST gave a 63 ps/gate propagation delay time and 0.043 pJ/gate speed-power product.