Naveen K. Yanduru

A 0.8mm 2 all-digital SAW-less polar transmitter in 65nm EDGE SoC

EDGE is currently the most widely used standard for data communications in mobile phones. Its proliferation has led to a need for low-cost 2.5G mobile solutions. The implementation of RF circuits in nanoscale digital CMOS with no or minimal process enhancements is one of the key obstacles limiting the complete SoC integration of cellular radio functionality with digital baseband. The key challenges for such RF integration include non-linearity of devices and circuits, device mismatches, process parameter spread, and the increasing potential for self-interference that could be induced by one function in the SoC onto another.

A WCDMA, GSM/GPRS/EDGE receiver front end without interstage SAW filter

A dual mode RF receiver for DCS band in 90 nm CMOS is presented. The receiver uses direct conversion for WCDMA mode and uses 100 kHz low IF for GSM/GPRS/EDGE (GGE) mode. The receiver does not use an interstage SAW filter between LNA and mixer. The mixer stage is followed by a variable gain amplifier. Two times LO clock is provided from external source and a divide by two is used to generate quadrature clocks. The receiver has a NF of 2.9 dB and meets all the out of band and in band linearity requirements for both WCDMA and GGE modes

A 90nm CMOS single-chip GPS receiver with 5dBm out-of-band IIP3 2.0dB NF

A single-chip GPS receiver with a low-IF heterodyne RF front-end includes a LNA, image-reject IQ mixers, a passive poly-phase filter, and a fully integrated synthesizer. The IF-strip consists of a jammer-reject filter, a VGA, a /spl Delta//spl Sigma/ ADC, and a digital IF-filter. The receiver dissipates 60 mA at 1.4 V and achieves a NF of 2 dB and out-of-band IIP3 of 5 dBm.

A direct-conversion receiver for the 3G WCDMA standard

A highly integrated direct-conversion receiver that satisfies requirements of the third-generation wide-band code-division multiple-access mobile phone standard is described. The receiver integrated circuit includes the front-end low-noise amplifier, downconversion mixers, baseband variable-gain amplifiers, channel-select filters, and the frequency synthesizer. External components are limited to matching elements required for the low-noise amplifier and the mixers and two passive band-select filters. The receiver is implemented in a SiGe BiCMOS process and consumes a total current of 46 mA from a 2.7-V supply.

A direct conversion receiver for the 3G WCDMA standard

A highly integrated direct-conversion receiver that satisfies requirements of the third generation Wideband Code Division Multiple Access (WCDMA) mobile phone standard is described. The receiver IC includes the front-end low-noise amplifier, down-conversion mixers, channel select filters, baseband variable gain amplifiers, and the entire frequency synthesizer, including the voltage controlled oscillator, buffers and phase-locked loop.

A highly integrated GPS front-end for cellular applications in 90nm CMOS

A GPS receiver front-end consisting of an LNA and a mixer implemented in a 90 nm CMOS process is presented. The measured performance satisfies the linearity requirement set by cellular blockers, without requiring an external LNA or SAW filter that are typically used in GPS receivers for cellular applications. A highly linear RF mixer is designed for this purpose that exploits the short channel effect of deep sub-micron CMOS. The LNA has a single-ended input and provides a differential output. The front-end achieves 38 dB of voltage gain and a noise figure of 1.8 dB. The IIP3 performance is a function of the offset between the GPS signal and the two-tone interferers and varies from -6 dBm to 15 dBm. The NF degradation in the presence of a -30 dBm DCS band blocker is less than 0.5 dB.

RF receiver front-end with +3dBm out-of-band IIP3 and 3.4dB NF in 45nm CMOS for 3G and beyond

A receiver front-end in standard 45 nm CMOS technology is presented. The receiver achieves WCDMA system performance without requirement for an inter-stage SAW filter. High out-of-band linearity performance is achieved by reducing the RF circuitry and filtering the out-of-band blockers after direct conversion. For the receiver at 1.9 GHz, a +3.1 dBm IIP3 is achieved for blockers at 40 MHz and 80 MHz away from the RF carrier. NF is 3.4 dB, out-of-band IIP2 is +51 dBm and current is 19.5 mA for both I, Q channels with VDD of 1.4 V. LO is provided using an on-chip VCO followed by a quadrature divider.

Analysis and Measurement Of Self Mixing Of Transmitter Leakage in WCDMA Receivers

In this paper we analyze and measure the distortion due to self-mixing of transmitter (TX) leakage in WCDMA mobile receivers (RX). The self-mixing is primarily due to the second order non linearity of the mixer, which is very significant in WCDMA receivers due to the high power of the TX leakage signal. Existing published work has analyzed the dependence of this distortion, on the TX leakage power and second order non-linearity of the mixer. We go one step further and derive closed form expression for this distortion as a function of the power level of the TX, the second order nonlinearity of the mixer, and the number of equal power WCDMA channels in the TX leakage signal. This is also verified against measurements on a WCDMA receiver Chip

Signal Distortion Due To Spectral Re-Growth Of Adjacent Channel Interferers in WCDMA Receivers

In WCDMA receivers, WCDMA modulated adjacent channel interferers (ACI) can distort the useful signal due to non linearity of the front end RF components. Non linearity of the RF front end transfers the modulation of the transmitter (TX) leakage onto the ACI, resulting in cross-modulation distortion. In addition to this, if the ACI signal is strong, it would undergo spectral re-growth and some fraction of its power will leak into the adjacent desired channel. The adjacent channel selectivity (ACS) scenarios in the 3GPP RX specification outline the performance requirement for the receiver in the presence of a strong as well as a weak ACI signal. For the ACS high power scenario (in which the ACI signal is strong), the distortion due to ACI leakage is much more significant compared to the cross-modulation distortion. Therefore, understanding the ACI leakage distortion becomes important, in order to ensure reliable receiver performance. In this paper, we analyze and report observations of the ACI leakage phenomenon on a WCDMA receiver chip. Measurement results have also been reported for the 3GPP ACS high power scenario. The chip measurements are supported with time-domain simulation results

Analysis and Measurement of Cross Modulation Distortion in WCDMA Receivers

Due to nonlinearity of the front end RF components in a WCDMA receiver, the modulation of the leaked transmitter (TX) signal can get transferred to a blocker, resulting in cross-modulation. If the blocker is close to the desired channel, the cross-modulation spectrum would contaminate the desired channel. Previous published work has analyzed cross-modulation but only for the cases when the leaked TX signal has one or infinite number of physical channels. In this paper, the authors perform more exhaustive analysis, and derive a closed form expression for the distortion as a function of a generic (N) number of channels in the leaked TX signal. This analysis is also supported with measurements on a WCDMA chip