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High-speed monolithic converters norrpally use a variation of the flash technique, which uses 2n comparators in parallel to obtain a fast n-bit conversion. Although this method allows for high converter bandwidth, it is not very area efficient,~d results in large dle sizes for even modest resolution c~nverters. In the technique presented here, a number of small but Vea efficient converters are operated in a time-interleaved fashion. to achieve the bandwidth of a flash 'circuit, but in a substantially smaller area. This technique is analyzed with respect to noise~d distortion resulting from nonidesl array characteristics, aqd is~emonstrated by way of a four-way array test-chip. This qhip consists" of four time-interleaved 7-bit wei~ted-capacitor A/D converte~sj fabricated in a 10 #m metal-gate CMOS process. Full 7-bit kine~ity @ maintained up to a 2.5 MHz conversion rate, with operation at feduced liiearity continukg to~pproximately 4 MHz. The design of this chip, and anticipated characteristics if fabricated in a modern 4-5 '&mprocess tie describe&

Programmable logic functions may be realized with giant-magnetoresistance or spin-dependent tunneling devices in conjunction with relatively simple circuitry. These functions may be implemented as conventional programmed logic arrays using the magnetic devices as nonvolatile programming elements or as arrays of universal logic gates whereby the core logic functions are magnetically programmed. Both methodologies are described in this article along with rapidly reconfigurable variations that have applications in high performance and adaptive computing. Various design considerations of these schemes are presented along with simulation results of proposed circuits. Among the potential advantages of these magnetic logic devices are nonvolatility of both programming information and data and the ability to reconfigure an entire logic array into any one of a number of configurations in a single clock cycle.

Molecular attractions are measured between pairs of flat quartz plates and between a flat and a spherically curved plate. Considerable precautions are taken against spurious electric charges, dust and gel particles which might interfere with the measurements. Silicone oil is used for damping. Distances between the flat plates have been varied from 5000-9500 A, and from 940-5000 A for the plate and sphere combination. Attraction forces varied from 0.002-0.3 dyne. The results agree with the presence of retarded van der Waals' forces (Casimir and Polder, Lifshitz). If the force per unit area between flat plates is represented by F = --B/d4, the value of B = 1-2x 10-19 erg cm, is in good agreement with existing theories, and with the previous experimental results obtained by Derjaguin and Abrikosova and by Kitchener and Prosser. An explanation is suggested why earlier measurements by Overbeek and Sparnaay using a similar method led to much stronger attractions.

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