A Wideband Energy-Efficient Multi-Mode CMOS Digital Transmitter

This article presents a wideband, energy-efficient digital transmitter (DTX) suitable for multi-mode/multi-band wireless communication applications. It features various operation modes comprising Cartesian (Modes-1/-2) and multi-phase (Modes-3/-4) configurations utilizing LO clocks with different duty cycle in the interleaving/non...

A Fractional-N Digitally Intensive PLL Achieving 428-fs Jitter and <-54-dBc Spurs Under 50-mV _ppSupply Ripple

In this article, we present a 4.5-5.1-GHz fractional-N digitally intensive phase-locked loop (DPLL) capable of maintaining its performance in face of a large supply ripple, thus enabling a direct connection to a switched-mode dc-dc converter. Supply pushing of its inductor-capacitor (LC) oscillator is suppressed by properly replicating the...

High-Power Digital Transmitters for Wireless Infrastructure Applications (A Feasibility Study)

Fully digital transmitters (DTXs) have the potential of replacing analog-intensive transmitter (TX) line-ups in future massive multiple-input and multiple-output (mMIMO) systems since they hold the promise of higher system integration level and energy efficiency. DTX operation so far has been limited to low RF output powers. This article...

A Wideband IQ-Mapping Direct-Digital RF Modulator for 5G Transmitters

This article presents a wideband 2× 12 -bit direct-digital RF modulator (DDRM) operating in a 0.5-to-3-GHz band for 5G transmitters. The proposed digital Cartesian modulator features an advanced IQ-mapping technique to boost RF power by 3 dB and suppress the I/Q image. To verify the proposed concept, a 40-nm CMOS prototype is implemented...

Versatile DAC-less successive approximation ADC architecture for medium speed data acquisition

Implementation of the DAC is usually the bottleneck in designing a SAR ADC. Here an innovative DAC-less SAR (DLSAR) ADC architecture is presented which alleviates some drawbacks of the conventional SAR counterpart. The proposed DLSAR binary search algorithm is comprised of two arithmetic operations of division-by-two and subtraction to...

A Wideband Four-Way Doherty Bits-In RF-Out CMOS Transmitter

We present a wideband, 12-bit four-way Doherty Cartesian digital transmitter (DTX) featuring an innovative 50%-LO signed I/Q interleaved up-conversion technique that enables close to perfect orthogonal I/Q summation. The DTX incorporates a compact four-way lumped-element Doherty power combining network to enhance its average efficiency at...

A 31-μ W, 148-fs Step, 9-bit Capacitor-DAC-Based Constant-Slope Digital-to-Time Converter in 28-nm CMOS

This article proposes a power-efficient highly linear capacitor-array-based digital-to-time converter (DTC) using a charge redistribution constant-slope approach. A fringe-capacitor-based digital-to-analog converter (C-DAC) array is used to regulate the starting supply voltage of the constant discharging slope fed to a fixed-threshold...

A High-Speed 40-channel USB 3.0 DAC for Adaptive Optics

A High-Speed Digital-to-Analog converter system is proposed that is controlled using USB 3.0. Possibilities to improve the refresh rate and resolution are researched to meet the standards of modern measurement systems. For instance, adaptive optics often uses a DAC in its feedback loop, but the USB DAC systems currently available provide...

All-Digital I/Q RF-DAC

Due to the severe cost pressure of consumer electronics, a migration to an advanced nanoscale CMOS processes, which is primarily developed for fast and low-power digital circuits operating at low supply voltages, is necessary, but it forces wireless RF transceivers to exploit more and more digital circuitry. These basic CMOS properties tend to...

A Wideband 2x13-bit All-Digital I/Q RF-DAC

This paper presents a wideband 2 13-bit in-phase/quadrature-phase (I/Q) RF digital-to-analog converter-based all-digital modulator realized in 65-nm CMOS. The isolation between I and Q paths is guaranteed employing 25% duty-cycle differential quadrature clocks. With a 1.3-V supply and an on-chip power combiner, the digital I/Q transmitter...

Sampling time error calibration in Time-interleaved ADCs

High-speed and high-resolution analog-to-digital and digital-to-analog converters

Analog-to-digital and digital-to-analog converters are important building blocks connecting the analog world of transducers with the digital world of computing, signal processing and data acquisition systems. In chapter two the converter as part of a system is described. Requirements of analog filtering of input signals before they are applied...