A 0.4-μm CMOS 10-Gb/s 4-PAM pre-emphasis serial link transmitter

A serial link transmitter fabricated in a large-scale integrated 0.4-μm CMOS process uses multilevel signaling (4-PBM) and a three-tap pre-emphasis filter to reduce intersymbol interference (ISI) caused by channel low-pass effects. Due to the process-limited on-chip frequency, the transmitter output driver is designed as a 5:1 multiplexer to reduce the required clock frequency to one-fifth the symbol rate, or 1 GHz. At 5 Gsym/s (10 Gbis), a data eye opening with a height >350 mV and a width >100 ps is achieved at the source. After 10 m of a copper coaxial cable (PE142LL), the eye opening is reduced to 200 mV and 90 ps with pre-emphasis, and to zero without filtering, The chip dissipates 1 W with a 3.3-V supply and occupies 1.5×2.0 mm² of die area     

A low-power 8-PAM serial transceiver in 0.5-μm digital CMOS

An 8-PAM CMOS transceiver is described in this paper. Pre-emphasis is implemented without an increase in DAC resolution or digital computation. The receiver oversamples with three fully differential 3-bit ADCs. The prototype transmits at up to 1.3 Gb/s and has a measured bit error rate of less than 1 in 10¹³ for an 810-Mb/s pseudorandom bit sequence transmission. The device, packaged in a 68-pin ceramic leadless chip carrier, is implemented in 0.5-μm digital CMOS, occupies 2 mm², and dissipates 400 mW from a 3.3-V supply     

A 0.5-μm CMOS 4.0-Gbit/s serial link transceiver with datarecovery using oversampling

A 4-Gbit/s serial link transceiver is fabricated in a MOSIS 0.5-μm HPCMOS process. To achieve the high data rate without speed critical logic on chip, the data are multiplexed when transmitted and immediately demultiplexed when received. This parallelism is achieved by using multiple phases tapped from a PLL using the phase spacing to determine the bit time. Using an 8:1 multiplexer yields 4 Gbits/s, with an on-chip VCO running at 500 MHz. The internal logic runs at 250 MHz. For robust data recovery, the input is sampled at 3× the bit rate and uses a digital phase-picking logic to recover the data. The digital phase picking can adjust the sample at the clock rate to allow high tracking bandwidth. With a 3.3-V supply, the chip has a measured bit error rate (BER) of <10^-14     

An area-power efficient 4-PAM full-clock 10-Gb/s CMOS pre-emphasis serial link transmitter

This paper presents a new area-power efficient 4-PAM full-clock CMOS pre-emphasis transmitter for 10-Gb/s serial links. The proposed transmitter reduces the chip area and power consumption by minimizing the number of digital-to-analog converters for 4-PAM signaling and pre-emphasis. In addition, a new full-clock scheme is proposed to double the data rate without increasing the sampling clock frequency. To assess the effectiveness of the proposed transmitter, a 8-to-1 serial link consisting of the proposed transmitter and a pair of terminated microstrip lines with a FR4 substrate has been implemented in TSMC 0.18 μm 1.8 V CMOS technology and analyzed using SpectreRF from Cadence Design Systems with BSIM3.3V transistor models that count for both device parasitics and second-order effects. Simulation results are presented.     

A CMOS multichannel 10-Gb/s transceiver

We describe a CMOS multichannel transceiver that transmits and receives 10 Gb/s per channel over balanced copper media. The transceiver consists of two identical 10-Gb/s modules. Each module operates off a single 1.2-V supply and has a single 5-GHz phase-locked loop to supply a reference clock to two transmitter (Tx) channels and two receiver (Rx) channels. To track the input-signal phase, the Rx channel has a clock recovery unit (CRU), which uses a phase-interpolator-based timing generator and digital loop filter. The CRU can adjust the recovered clock phase with a resolution of 1.56 ps. Two sets of two-channel transceiver units were fabricated in 0.11-/spl mu/m CMOS on a single test chip. The transceiver unit size was 1.6 mm /spl times/ 2.6 mm. The Rx sensitivity was 120-mVp-p differential with a 70-ps phase margin for a common-mode voltage ranging from 0.6 to 1.0 V. The evaluated jitter tolerance curve met the OC-192 specification.     

A 965-Mb/s 1.0-μm standard CMOS twin-pipe serial/parallelmultiplier

This paper presents a two's complement high-speed twin-pipe serial/parallel multiplier architecture which produces y=cd, where c is the parallel coefficient and d is the serial data. The multiplier is based on the twin pipeline (twin-pipe) concept, in which two data bits are processed each clock cycle. The high serial data throughput rate is mainly due to the use of: 1) a novel twin-pipe architecture, 2) new twin-pipe adder types, and 3) a new multiplier circuit structure. A 4-bit high-speed twin-pipe serial/parallel multiplier, on an active area of 0.224 mm², has been designed and fabricated in a 1.0-μm N-well double-metal single-poly CMOS process. Testing of the multiplier shows that the maximal serial data throughput rate is 965 Mb/s at V_dd=5 V     

A serial-link transceiver based on 8-GSamples/s A/D and D/Aconverters in 0.25-μm CMOS

This paper presents a transceiver that uses a 4-bit flash analog-to-digital converter (ADC) for the receiver and an 8-bit current-steering digital-to-analog converter (DAC) for the transmitter. The 8-GSamples/s converters are 8-way time interleaved. Digital compensation reduces the input offset of the ADC comparators to less than 0.6 LSB, improves the accuracy of the interleaved sampling clocks to within 10 ps, and reduces systematic coupling noise to less than 18 mV on the 800-mV signal swing. 1.1-nH bondwire inductors distribute the parasitic capacitances at the transceiver input and output, reducing attenuation by 10 dB at 4 GHz. Equalization algorithms using the converters compensate for the 1.5-GHz transceiver bandwidth to allow 8-GSamples/s multilevel data transmission     

2.8-Gb/s 176-mW byte-interleaved and 3.0-Gb/s 118-mWbit-interleaved 8:1 multiplexers with a 0.15-μm CMOS technology

This paper reports the first CMOS implementation of an 8:1 byte-interleaved multiplexer (byte-MUX) operating in the Gb/s region, together with an 8:1 bit-interleaved multiplexer (bit-MUX). A future generation 0.15-μm CMOS technology has been applied. Both chips use identical bit-MUX cores with a static shift-register architecture, and have ECL interfaces with a single supply of -2 V. The byte-MUX demonstrates 43-mW/GHz dependence on clock frequency and operates up to 2.8 Gb/s with a power dissipation of 176 mW. The bit-MUX showed 20-mW/GHz dependence on clock frequency and operated up to 3.0 Gb/s with a power dissipation of 118 mW. This revel of performance has been achieved by a novel row-column exchanger configuration, critical path reduction and precise clocking techniques utilized in the bit-MUX core, and the development of high-speed I/O buffers     

A 1-Gb/s, 0.7-μm CMOS optical receiver with full rail-to-railoutput swing

This paper presents a 1-Gb/s optical receiver with full rail-to-rail output swing realized in a standard 0.7-μm CMOS technology. The receiver consists of a 1-kΩ transimpedance preamplifier followed by a postamplifier based on a biased inverter chain. The latter performs both a linear and a limiting amplification. The automatic biasing of the chain is provided through an offset tolerant replica circuit. The receiver requires no external components or biasing voltages. It is designed for a relatively large 0.8-pF input capacitance and is fed from a single 5-V power supply. These properties make the circuit suitable for a commercial environment. A sensitivity of 10 μA was measured at 1 Gb/s. The complete receiver, including all biasing and replicas, consumes approximately 100 mW from the 5-V supply. When powered from a 3.3-V supply, a maximal bit rate of 600 Mb/s is achieved, while the power consumption is reduced to approximately 26.5 mW     

An 8-Gb/s/pin simultaneously bidirectional transceiver in 0.35-/spl mu/m CMOS

This paper presents architecture, circuits, and test results for a single-ended, simultaneously bidirectional interface capable of a total throughput of 8 Gb/s per pin. The interface addresses noise reduction challenges by utilizing a pseudodifferential reference with noise immunity approaching that of a fully differential reference. The transmitter supports on-chip termination, predistortion, and low-skew near-end outgoing signal echo cancellation. The receiver's sense amplifier evaluates the average of two differential input signals without use of analog components and utilizes imbalanced charge injection to compensate for offset voltages. A test chip integrated in a 0.35-/spl mu/m digital CMOS technology uses the proposed techniques to implement an 8-bit wide single-ended voltage-mode simultaneous bidirectional interface and achieves a performance of 8 Gb/s per pin.     

Equalization and clock recovery for a 2.5-10-Gb/s 2-PAM/4-PAM backplane transceiver cell

A folded multitap transmitter equalizer and multitap receiver equalizer counteract the losses and reflections present in the backplane environment. A flexible 2-PAM/4-PAM clock data recovery circuit uses select transitions for receive clock recovery. Bit-error rate less than 10/sup -15/ and power equal to 40 mW/Gb/s has been measured when operating over a 20-in backplane with two connectors at 10 Gb/s.     

GSM transceiver front-end circuits in 0.25-μm CMOS

So far, CMOS has been shown to be capable of operating at radio-frequency (RF) frequencies, although the inadequacies of the device-level performance often have to be circumvented by innovations at the architectural level that tend to shift the burden to the circuit building blocks at lower frequencies, The RF front-end circuits presented in this paper show that excellent RF performance is feasible with 0.25-μm CMOS, even in terms of the requirements of the tried-and-true superheterodyne architecture. Design for low-noise and low-current consumption targeted for GSM handsets has been given particular attention in this paper. Low-noise amplifiers with sub-2-dB noise figures (NFs) and a double balanced mixer with 12.6 dB single-sideband NF, as well as sub-25-mA current consumption for the RF front end (complete receiver), are among the main achievements     

An adaptive PAM-4 5-Gb/s backplane transceiver in 0.25-/spl mu/m CMOS

This paper describes a backplane transceiver, which uses pulse amplitude modulated four-level (PAM-4) signaling and continuously adaptive transmit-based equalization to move 2.5-GBd/s symbols totalling 5 Gb/s across typical FR-4 backplanes for total distances of up to 50 inches through two sets of backplane connectors. The 17-mm/sup 2/ device is implemented in a 0.25-/spl mu/m CMOS process, operates off of 2.5- and 3.3-V supply voltages, and consumes 1 W.     

A 10-Gb/s (1.25 Gb/s×8)4×2 0.25-μm CMOS/SIMOX ATMswitch based on scalable distributed arbitration

This paper presents the design and implementation of a scalable asynchronous transfer mode switch. We fabricated a 10-Gb/s 4×2 switch large-scale integration (LSI) that uses a new distributed contention control technique that allows the switch LSI to be expanded. The developed contention control is executed in a distributed manner at each switch LSI, and the contention control time does not depend on the number of connected switch LSI's. To increase the LSI throughput and reduce the power consumption, we used 0.25-μm CMOS/SIMOX (separation by implanted oxygen) technology, which enables us to make 221 pseudo-emitter-coupled-logic I/O pins with 1.25-Gb/s throughput. In addition, power consumption of 7 W is achieved by operating the CMOS/SIMOX gates at -2.0 V. This consumption is 36% less than that of bulk CMOS gates (11 W) at the same speed at -2.5 V. Using these switch LSI's, an 8×8 switching multichip module with 80-Gb/s throughput was fabricated with a compact size     

0.3-μm mixed analog/digital CMOS technology for low-voltageoperation

A 0.3-μm mixed analog/digital CMOS technology for low-voltage operation has been demonstrated, including a new MOSFET structure with laterally doped buried layer (LDB) and a double-polysilicon capacitor with low voltage coefficient. The LDB-structure MOSFET provides constant threshold voltage which is independent of channel length, high current drivability 10% over that of a conventional structure, and low junction capacitance which is less than 1/2 that of the conventional structure. The double-polysilicon capacitor achieves a voltage coefficient of 1/10 that of a conventional capacitor by introducing arsenic ion implantation to the top polysilicon plate and a Si₃N₄ capacitor-insulator, despite the insulator thickness being scaled down to oxide-equivalent 20 nm     

An area-power efficient CMOS 4-PAM class AB current-mode pre-emphasis serial link transmitter

This paper presents an area-power efficient CMOS 4-PAM class AB current-mode pre-emphasis transmitter for multi-Gb/s serial links. The proposed transmitter minimizes both chip area and power consumption by constructing pre-emphasis symbols directly from the current symbol, eliminating the need for complex FIR filters and digital-to-analog converters. The differential output current obtained from a class AB pre-amplifier and the push-pull operation of both the current-symbol and pre-emphasis drivers minimizes the electromagnetic interference exerted by channels to neighboring devices. The use of latches at both the multiplexer and pre-amplifier minimizes the effect of power fluctuation and ground bouncing on the output current of the transmitter. The proposed transmitter has been implemented in both UMC-0.13 μm 1.2 V and TSMC-0.18 μm 1.8V CMOS technologies and analyzed using SpectreRF from Cadence Design Systems with BSIM3.3v device models. The effectiveness of the proposed transmitter architecture is validated from the simulation results of both designs.     

1.2-Gb/s true PECL 100K compatible I/O interface in 0.35-μm CMOS

This paper describes the design and the implementation of input-output (I/O) interface circuits for serial data links in the gigabit-per-second range. The cells were implemented in a 3.3-V 0.35-μm CMOS technology in a couple of test chips. The transmitter is fully compatible (DC coupling) with 100K positive emitter-coupled logic (PECL) systems and it is based on the voltage-switching principle in order to allow different termination schemes besides the canonical ECL termination, i.e., 50-Ω toward (V_DD-2) V. The addition of some circuit techniques such as dynamic biasing and strobed current switching boosts the dynamic performance of the basic voltage-switching scheme and relaxes the requirements for a high bias current and large-size output devices at the same time. Moreover, thanks to the developed reference circuit, using both feedforward and feedback controls, the output levels are within the 100K tolerance over the full range of process, supply voltage, and temperature (PVT) variations without resorting to external components or on-chip trimming. The receiver cell is based on a complementary-differential architecture providing high speed and low error on the duty cycle of the CMOS output signal. The integrated receiver-transmitter chain exhibits a maximum toggle frequency of 1 GHz, while a chip-to-chip transmission link using the developed I/O interface was tested up to 1.2 Gb/s     

A quad 0.6-3.2 Gb/s/channel interference-free CMOS transceiver for backplane serial link

A quad-channel 0.6-3.2 Gb/s/channnel transceiver using eight independent phase-locked loops (PLLs) shows a 1-ps rms random jitter performance without interchannel interference. The PLL employs a folded starved inverter with high supply/substrate noise immunity and an analog coarse-tuning scheme for both seamless frequency acquisition and N-fold voltage-controlled-oscillator (VCO) gain reduction. A fixed-interval charge pumping is adopted for wide pumping-current range and large jitter tolerance. A wide-range delayed-locked loop (DLL) is utilized as a clock and reset generator for an elastic buffer. The transceiver, implemented in a 0.18-/spl mu/m CMOS technology, operates across a 30-in FR-4 backplane up to 3.2 Gb/s/ch with a bit-error rate of less than 10/sup -13/.     

Integrated laser-diode voltage driver for 20-Gb/s optical systemsusing 0.3-μm gate length quantum-well HEMT's

An integrated laser-diode voltage driver (LDVD) making use of enhancement/depletion AlGaAs-GaAs quantum-well high electron mobility transistors (QW HEMTs) with gate lengths of 0.3 μm has been developed. Its large signal bandwidth is 12 GHz. Eye diagrams of the output signal at bit rates up to 8 Gb/s show an opening similar to that of the input signal. Supporting material is given indicating that the LDVD might operate at bit rates up to 20 Gb/s. The maximum output current is over 90 mA; the maximum modulation voltage of 800 mV corresponds to 40-mA modulation current for a laser diode with 20-Ω dynamic resistance. The power consumption is less than 500 mW