A high-speed high-density silicon 8/spl times/8-bit parallel multiplier

An 8/spl times/8-bit parallel multiplier with submicrometer gate lengths has been fabricated using silicon NMOS technology. The multiplication time is 9.5 ns. This corresponds to an average loaded gate delay in the multiplier circuit of 244 ps/gate, which the authors believe is the shortest gate delay for MOS multiplier circuits demonstrated to date. The power dissipation is 600 mW at a supply voltage of 5 V. The multiplier circuit has a total of 1427 transistors in an active area of 0.61/spl times/0.58 mm/SUP 2/, corresponding to a gate density of 1125 gates/mm/SUP 2/.     

1.5 V 1 K-CMOS-RAM with only 8 pins

A 256-bit/spl times/4-bit static RAM working on a supply voltage down to 1.2 V is described. A serial interface for the address and the data with a 4-bit bus reduces the pincount of the RAM to only 8. Special design techniques to reach the design goal-very low power at a reasonable circuit speed-are discussed in detail. The device is fabricated in a low power silicon gate CMOS process. An operating power of 500 /spl mu/W/MHz and a standby power of less than 1 /spl mu/W at 1.5 V supply voltage was achieved. With this serial interface a cycle time of 1 /spl mu/s at 1.5 V was measured.     

10 ns 8/spl times/8 multiplier LSI using super self-aligned process technology

Describes a high-speed 8/spl times/8 bit multiplier LSI which uses the newly developed high-speed and low-power bipolar process technology SST-2. SST-2 results in 250 ps delay time and 0.165 pJ power delay product in a low-level current mode logic (LCML) gate. Its multiplication time is about 10 ns, and its power dissipation is about 660 mW. This LSI has a feature called `perfect expandability' for arbitrary scaling of the expanded 8n/spl times/8n bit multiplier without an additional circuit. The results indicate that 32/spl times/32 bit multiplication can be carried out with 55 ns.     

A 2-/spl mu/m CMOS 8-MIPS digital processor with parallel processing capability

A 2-/spl mu/m CMOS VLSI digital signal processor (DSP) family, the SP50, is described that is capable of eight million instructions per second and up to six concurrent operations in each instruction. Two DSPs, the PCB5010 and PCB5011, have been developed. Both are based on a common architecture which contains two 16-bit data buses, and a 16/spl times/16/spl rarr/40-bit multiplier accumulator and 16-bit ALU, both with multiprecision support in hardware. Also implemented are two static data RAMs (128/spl times/16 or 256/spl times/16), a data ROM (51/spl times/16), a 15-word three-port register file, three address computation units, and five serial and parallel I/O interfaces. The data path is controlled by an orthogonal instruction set, using 40-bit microcode words. The controller contains a five-level stack and an instruction repeat register, and can have either on-chip program memory (RAM: 32/spl times/40; ROM: 987/spl times/40) or off-chip program memory (up to 64K/spl times/40). Benchmarks show a two to sixfold improvement in overall performance over its predecessors.     

An experimental multiplier circuit based on superconducting Josephson devices

This paper describes the design, testing, and operation of a 4-bit multiplier circuit based on Josephson tunneling logic (JTL) gates. The algorithm adopted was that of a simple serial 4-bit multiplier consisting of a 4-bit adder with ripple carry, together with a four phase, 8-bit accumulator shift register. The circuit, fabricated using a 25-/spl mu/m minimum linewidth technology, operated with a minimum cycle time of 6.67 ns (a limit imposed by the external test equipment) giving a 4-bit multiplication time of 27 ns with an average power dissipation of 35 /spl mu/W per logic gate. With better external pulse generators, or internal Josephson junction generators, the present circuit has been simulated to operate with a 3.0-ns cycle giving a 4-bit multiplication time of 12 ns.     

A Pipelined 330-MHz Multiplier

An 8X8-bit multiplier test circuit developed in a 1-/spl mu/m NMOS technology is described. To achieve a high throughput rate, extensive pipelining is used in a semi-systolic fashion. It is shown that this saves area and allows for shorter cycle times compared to a pure systolic array. Problems with widely distributed lines (broadcasting) are avoided by a novel carry-save-adder cell. The data inputs and outputs are ECL compatible. The circuit contains 5480 MOSFET's in an active area of 0.6 mm/sup 2/. Effective channel lengths of 0.9 and 1.1 /spl mu/m are utilized for the enhancement and depletion transistors with a gate oxide thickness of 12.5 nm. The power dissipation is 1.5 W at a supply voltage of 3 V. The test chip operates up to a clock frequency of 330 MHz at room temperature and up to 600 MHz with liquid nitrogen cooling. This demonstrates the applicability of large-scale integrated MOS circuits in a frequency range of several hundred megahertz.     

A high-speed multiplier using a redundant binary adder tree

A 16-bit /spl times/ 16-bit multiplier for 2 two's-complement binary numbers based on a new algorithm is described. This multiplier has been fabricated on an LSI chip using a standard n-E/D MOS process technology with a 2.7-/spl mu/m design rule. This multiplier is characterized by use of a binary tree of redundant binary adders. In the new algorithm, n-bit multiplication is performed in a time proportional to log/SUB 2/ n and the physical design of the multiplier is constructed of a regular cellular array. This new algorithm has been proposed by N. Takagi et al. (1982, 1983). The 16-bit/spl times/16-bit multiplier chip size is 5.8 /spl times/ 6.3 mm/SUP 2/ using the new layout for a binary adder tree. The chip contains about 10600 transistors, and the longest logic path includes 46 gates. The multiplication time was measured as 120 ns. It is estimated that a 32-bit /spl times/ 32-bit multiplication time is about 140 ns.     

1.5 V four-quadrant CMOS current multiplier/divider

A low voltage CMOS four-quadrant current multiplier/divider circuit is presented. It is based on a compact V-I converter cell able to operate at very low supply voltages. Measurement results for an experimental prototype in a 0.8 /spl mu/m CMOS technology show good linearity for a /spl plusmn/15 /spl mu/A input current range and a 1.5 V supply voltage.     

CMOS/SOS serial-parallel multiplier

A 24-bit serial-parallel multiplier was integrated in CMOS/silicon-on-sapphire (SOS) technology on a 155 mil/spl times/170 mil chip. The operation of this multiplier is described, showing how the parallel loaded multiplier x combines with the serial loaded multiplicand, a, to form the serial product. An addend, b, can also be accommodated to produce ax+b. The design of the multiplier cells are based on functional majority logic adders and weak or trickle inverter master-slave latches. The chip operates at clock rates up to 18 MHz. Power dissipation at 10 MHz and V/SUB DD/ of 5 V is about 20 mW, and the energy consumption for multiplying two 16-bit numbers is about 64 nJ. Typical application areas are mentioned.     

A 70-MHz 8-bit/spl times/8-bit parallel pipelined multiplier in 2.5-/spl mu/m CMOS

A design is presented for an 8-bit/spl times/8-bit parallel pipelined multiplier for high speed digital signal-processing applications. The multiplier is pipelined at the bit level. The first version of this multiplier has been fabricated in 2.5-/spl mu/m CMOS technology. It has been tested at multiplication rates up to 70 MHz with a power dissipation of less than 250 mW. Clock skew, a major problem encountered in high-speed pipelined architectures, is overcome by the use of a balanced clock distribution network all on metal, and by proper use of clock buffers. These issues and the timing simulation of the pipeline design are discussed in detail. Possible extensions and improvements for achieving higher performance levels are discussed. The conversion of the two-phase clocking scheme to an inherently single-phase clock approach is one possible improvement. A design using this approach has been simulated at 75 MHz and is currently being fabricated.     

On-chip high-voltage generation in MNOS integrated circuits using an improved voltage multiplier technique

An improved voltage multiplier technique has been developed for generating +40 V internally in p-channel MNOS integrated circuits to enable them to be operated from standard +5- and -12-V supply rails. With this technique, the multiplication efficiency and current driving capability are both independent of the number of multiplier stages. A mathematical model and simple equivalent circuit have been developed for the multiplier and the predicted performance agrees well with measured results. A multiplier has already been incorporated into a TTL compatible nonvolatile quad-latch, in which it occupies a chip area of 600 /spl mu/m/spl times/240 /spl mu/m. It is operated with a clock frequency of 1 MHz and can supply a maximum load current of about 10 /spl mu/A. The output impedance is 3.2 M/spl Omega/.     

A self-aligned gate III-V heterostructure FET process forultrahigh-speed digital and mixed analog/digital LSI/VLSI circuits

A planar ion-implanted self-aligned gate process for the fabrication of high-speed digital and mixed analog/digital LSI/VLSI integrated circuits is reported. A 4-b analog-to-digital converter, a 2500-gate 8×8 multiplier/accumulator, and a 4500-gate 16×16 complex multiplier have been demonstrated using enhancement-mode n⁺ -(Al,Ga)As/MODFETs, superlattice MODFETs, and doped channel heterostructure field-effect transistors (FETs) whose epitaxial layers were grown by molecular-beam epitaxy. With nominal 1-μm gate-length devices, direct-coupled FET logic ring oscillators with realistic circuit structures have propagation delays of 30 ps/stage at a power dissipation of 1.2 mW/stage. In LSI circuit operation, these gates have delays of 89 ps/gate at a power dissipation of 1.38 mW/gate when loaded with an average fan-out of 2.5 gates and about 1000 μm of high-density interconnects. High-performance voltage comparator circuits operated at sampling rates greater than 2.5 GHz at Nyquist analog input rates and with static hysteresis of less than 1 mV at room temperature. Fully functional 4-b analog-to-digital circuits operating at frequencies up to 2 GHz were obtained     

An 8-bit 20-MS/s ZCBC Time-Domain Analog-to-Digital Data Converter

An 8-bit 20-MS/s time-domain analog-to-digital data converter (ADC) using the zero-crossing-based circuit technique is presented. Compared with the conventional ADCs, signal processing is executed in both the voltage and time domains. Since no high-gain operational amplifier is needed, this time-domain ADC works well in a low supply voltage. The proposed ADC has been fabricated in a 0.18-mum CMOS process. Its power dissipation is 4.64 mW from a supply voltage of 1.8 V. This active area occupies 1.2 times 0.7 mm². The measured signal-to-noise-distortion ratio achieves 44.2 dB at an input frequency of 10 MHz. The integral nonlinearity is less than plusmn1.07 LSB, and the differential nonlinearity is less than plusmn0.72 LSB. This time-domain ADC achieves the effective bits of 7.1 for a Nyquist input frequency at 20 MS/s.     

High-speed NMOS circuits for ROM-accumulator and multiplier type digital filters

Using a standard 6 /spl mu/m NMOS silicon-gate process, circuit techniques are described for the full integration of high-speed ROM-accumulator and multiplier type digital filters. The ROM-accumulator structure is integrated using a new two-clock four-phase technique which can be used both for ROM and accumulator. An operating speed of 20 Mbits/s is measured. The circuit shows that an eighth-order filter on a 20 mm/SUP 2/ chip, dissipating only 400 mW at 10 Mbits/s is feasible. Using a 4-clock 4-phase technique a 4-bit serial-parallel multiplier is presented featuring 20 Mbits/s operation into a 15 pF load. Power dissipation is 7 mW/cell. Cell area is 0.2 mm/SUP 2/.     

An 8-MHz CMOS subranging 8-bit A/D converter

A 8-bit subranging converter (ADC) has been realized in a 3-/spl mu/m silicon gate, double-polysilicon capacitor CMOS process. The ADC uses 31 comparators and is capable of conversion rates to 8 MHz at V/SUB DD/=5 V. Die size is 3.2/spl times/2.2 mm/SUP 2/.     

A 2K/spl times/8-bit static MOS RAM with a new memory cell structure

A 2K/spl times/8-bit static MOS RAM with a new memory cell structure has been developed. The memory cell consists of six devices including four MOSFETs and two memory load resistors. Two load resistors are fabricated in the second-level polysilicon films over the polysilicon gate MOSFET used as the driver. Thus the memory cell area is determined only by the area of four MOSFETs. By applying the new cell structure and photolithography technology of 3 /spl mu/m dimensions, the cell area of 23/spl times/27 /spl mu/m and the chip area of 3.75/spl times/4.19 mm have been realized. The RAM is nonclocked and single 5 V operation. Access time of about 150 ns is obtained at a supply current of 120 mA.     

A direct digital frequency synthesizer with fourth-order phase domain /spl Delta//spl Sigma/ noise shaper and 12-bit current-steering DAC

This paper presents a direct digital frequency synthesizer (DDFS) with a 16-bit accumulator, a fourth-order phase domain single-stage /spl Delta//spl Sigma/ interpolator, and a 300-MS/s 12-bit current-steering DAC based on the Q/sup 2/ Random Walk switching scheme. The /spl Delta//spl Sigma/ interpolator is used to reduce the phase truncation error and the ROM size. The implemented fourth-order single-stage /spl Delta//spl Sigma/ noise shaper reduces the effective phase bits by four and reduces the ROM size by 16 times. The DDFS prototype is fabricated in a 0.35-/spl mu/m CMOS technology with active area of 1.11mm/sup 2/ including a 12-bit DAC. The measured DDFS spurious-free dynamic range (SFDR) is greater than 78 dB using a reduced ROM with 8-bit phase, 12-bit amplitude resolution and a size of 0.09 mm/sup 2/. The total power consumption of the DDFS is 200mW with a 3.3-V power supply.     

Ultracompact SOI CMOS frequency doubler for low power applications at 26.5-28.5 GHz

In this paper, a complementary metal oxide semiconductor (CMOS) frequency doubler for wireless applications at Ka-band is presented. The microwave monolithic integrated circuit (MMIC) is fabricated using digital 90 nm silicon on insulator (SOI) technology. All impedance matching, filter and bias elements are implemented on the chip, which has a very compact size of 0.37 mm/spl times/0.27 mm. At an output frequency of 27 GHz, source/load impedances of 50 /spl Omega/, a supply voltage of 1.25 V, a supply current of 8 mA and an input power of -4.5 dBm, a conversion gain of 1.5 dB was measured. To the knowledge of the authors, the circuit has by far the highest operation frequency for a CMOS frequency multiplier reported to date and requires lower supply power than circuits using leading edge III/V and silicon germanium (SiGe) technologies.     

LSI multiplier using high speed ULG

The three-gating stage 4/spl times/4-bit multiplier design and its LSI realization using 34 ECL cascode cells are described. Use of a modular single-stage universal logic gate as the primary logic building block in the multiplier allows achievement of a factor of 2 delay reduction relative to multipliers described previously.     

A 500-MHz 16*16 complex multiplier using self-aligned gate GaAs heterostructure FET technology

A 16*16-bit complex multiplier using self-aligned gate GaAs heterostructure FET technology has been demonstrated. The multiplier uses a modified Booth's algorithm and three stages of pipeline with an embedded accumulator to allow the computation of a complex multiply function. A total of 4500 gates and over 20000 devices are required to implement this function and self-test functions. The chip produces a 20-bit output allowing 40 bits to describe a complex number result. Direct coupled NOR-gate FET logic was used throughout. The complex multiplier operated at a clock rate of 520 MHz with a power dissipation of 4 W under self-test. This corresponds to an average 'loaded' gate delay of 96 ps at 0.89 mW/gate. It also means that the multiplier produces a complex product, generated using four real multiplications and two additions, in less than 8 ns. This result demonstrates the high-speed capability of LSI digital circuits fabricated using MBE-grown GaAs heterostructure FET technology.<>