Analysis of a 5.5-V Class-D Stage Used in $+$30-dBm Outphasing RF PAs in 130- and 65-nm CMOS

Fritzin, Jonas; Svensson, Christer; Alvandpour, Atila

doi:10.1109/tcsii.2012.2228391

Cited by 6 publications

(4 citation statements)

References 24 publications

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“…A Class D SMPA [26,[34][35][36][37] can be implemented as an inverter driving an output load R L . Ideally, a Class D PA would exhibit 100 % percent efficiency (ignoring the parasitics).…”

Section: Class D Smpamentioning

confidence: 99%

All-Digital PWM Transmitters

Pasha

2019

Linköping Studies in Science and Technology. Dissertations

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Electronic devices with wireless connectivity are fast becoming a part of daily life. According to some estimates, in the next five years, 10 billion new devices with internet connectivity would be produced. To lower the costs and extend the battery life of electronic circuits, there is an increased interest in using lowcost, low-power CMOS circuits. By taking advantage of the higher integration capabilities of modern CMOS, the analog, digital, and radio circuits can be integrated on a single die, typically called a radio-frequency system-on-chip (RF-SoC). In an RF-SoC, most of the power is usually consumed by the radio circuits, especially the power amplifier (PA). Hence, to take advantage of the improved switching capability of transistors in modern CMOS, the use of switch-mode PAs (SMPAs) is becoming more popular. SMPAs exhibit a much higher efficiency as compared to their linear counterparts and can be easily integrated with the digital baseband circuits. To satisfy the demand for higher data throughput, modern wireless standards like LTE and IEEE 802.11 generate envelope-varying signals using advanced modulation schemes like M-QAM and OFDM. Among several other techniques, pulse-width modulation (PWM) allows for the amplification of the envelopevarying signals using SMPAs. The first part of this thesis explores techniques to improve the spectral performance of PWM-based transmitters. The proposed transmitters are fully digital, and the entire signal chain up to the PA can be implemented using the digital design flow, which is especially beneficial in sub-micron CMOS processes with low voltage headroom. A new transmitter is proposed that compensates for the aliasing distortion in polar PWM transmitters by using outphasing. The transmitter exhibits an improvement of up to 9 dB in dynamic range for a 1.4 MHz LTE uplink signal. The idea is extended to compensate for both image and aliasing distortions in all-digital implementations of polar PWM transmitters. By using a field programmable gate array (FPGA) and Class-D SMPAs, the proposed transmitter shows an improvement of up to 6.9 dBc in the adjacent channel leakage ratio (ACLR) and 10% in the error vector magnitude (EVM) for a 20 MHz LTE uplink signal. The proposed transmitter is fully programmable and can be easily adapted for multi-band and multi-standard transmission.

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“…A Class D SMPA [26,[34][35][36][37] can be implemented as an inverter driving an output load R L . Ideally, a Class D PA would exhibit 100 % percent efficiency (ignoring the parasitics).…”

Section: Class D Smpamentioning

confidence: 99%

All-Digital PWM Transmitters

Pasha

2019

Linköping Studies in Science and Technology. Dissertations

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“…VDD). Cost-sensitive applications such as the ubiquitous sensor ICs integrating the control circuits for high power and MEMS devices, and the embedded non-volatile memories in a single logic die [1][2][3][4][5][6][7][8][9] requires this HV switch circuit to be implemented using only low voltage logic transistors without special HV transistors, as it reduces the process cost significantly. The design of HV switch circuits is a challenging task when logic compatibility, power consumption, circuit reliability, and switching speed are all taken into consideration.…”

Section: Introductionmentioning

confidence: 99%

“…The HV switches in [2,3] incur static current dissipation during switching operation, preventing the output from switching rail-to-rail. Transistors used in other HV switch circuits [4][5][6][7] were subject to voltage overstress and hence these designs result in circuit reliability concerns. The HV switch proposed in [8,9] toggles between GND and 4 × VDD reliably when the boosted supplies (i.e.…”

Section: Introductionmentioning

confidence: 99%

Overstress-Free 4 × VDD Switch in a Generic Logic Process Supporting High and Low Voltage Modes

Song¹,

Kim²,

Kim³

2015

JSTS:Journal of Semiconductor Technology and Science

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“…Non-Isolated Combiner The Outphasing transmitters using non-isolated combiners [17,18,39] suffer from spectral regrowth and signal corruption at the output, as non-isolated combiners do not stop the signal from one transmission path to interfere with the signal in the other transmission path.…”

Section: Combinermentioning

confidence: 99%

Pulse-Width Modulated RF Transmitters

Haque¹

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To my mother, father, and uncle (mamoo), AbstractThe market for wireless portable devices has grown significantly over the recent years. Wireless devices with ever-increased functionality require high rate data transmission and reduced costs. High data rate is achieved through communication standards such as LTE and WLAN, which generate signals with high peak-to-average-power ratio (PAPR), hence requiring a power amplifier (PA) that can handle a large dynamic range signal. To keep the costs low, modern CMOS processes allow the integration of the digital, analog and radio functions on to a single chip. However, the design of PAs with large dynamic range and high efficiency is challenging due to the low voltage headroom.To prolong the battery life, the PAs have to be power-efficient as they consume a sizable percentage of the total power. For LTE and WLAN, traditional transmitters operate the PA at back-off power, below their peak efficiency, whereas pulse-width modulation (PWM) transmitters use the PA at their peak power, resulting in a higher efficiency. PWM transmitters can use both linear and SMPAs where the latter are more power efficient and easy to implement in nanometer CMOS. The PWM transmitters have a higher efficiency but suffer from image and aliasing distortion, resulting in a lower dynamic range, amplitude and phase resolution.This thesis studies several new transmitter architectures to improve the dynamic range, amplitude and phase resolution of PWM transmitters with relaxed filtering requirements. The architectures are suited for fully integrated CMOS solutions, in particular for portable applications.The first transmitter (MAF-PWMT) eliminates aliasing and image distortions while allowing the use of SMPAs by combining RF-PWM and band-limited PWM. The transmitter can be implemented using all-digital techniques and exhibits an improved linearity and spectral performance. The approach is validated using a Class-D PA based transmitter where an improvement of 10.2 dB in the dynamic range compared to a PWM transmitter for a 1.4 MHz of LTE signal is achieved.The second transmitter (AC-PWMT) compensates for aliasing distortion by combining PWM and outphasing. It can be used with switch-mode PAs (SMPAs) or linear PAs at peak power. The proposed transmitter shows better linearity, improved spectral performance and increased dynamic range as it does not suffer from AM-AM distortion of the PAs and aliasing distortion due to digital PWM. The idea is validated using push-pull PAs and the proposed transmitter shows an improvement of 9 dB in the dynamic range as compared v vi Abstract to a PWM transmitter using digital pulse-width modulation for a 1.4 MHz LTE signal.The third transmitter (MD-PWMT) is an all-digital implementation of the second transmitter. The PWM is implemented using a Field Programmable Gate Array (FPGA) core, and outphasing is implemented as pulse-position modulation using FPGA transceivers, which drive two class-D PAs. The digital implementation offers the flexibility to adapt the transmitter...

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Analysis of a 5.5-V Class-D Stage Used in $+$30-dBm Outphasing RF PAs in 130- and 65-nm CMOS

Cited by 6 publications

References 24 publications

All-Digital PWM Transmitters

All-Digital PWM Transmitters

Overstress-Free 4 × VDD Switch in a Generic Logic Process Supporting High and Low Voltage Modes

Pulse-Width Modulated RF Transmitters

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