A novel power-amplifier module for quad-band wireless handset applications

This paper presents a novel power-amplifier module (PAM) designed for GSM850-, GSM900 MHz, DCS1800- and PCS1900-MHz handset applications. The module combines an InGaP HBT power-amplifier integrated circuit, two integrated couplers, a dual-band logarithmic RF power detector/controller, and some additional passive components. The logarithmic RF power detector was implemented in the module to accomplish linear-in-decibel output power dependency. This allows the handset manufacturers to calibrate output power (Pout) at one or two points, with error as low as +/-0.3 dB, thus reducing test time in mass production. Due to higher accuracy, our novel design significantly reduces the power consumption during normal operation. Our design is the first to include two integrated directional couplers in a handset RF PAM. It significantly improves power control accuracy over load variations. In this paper, we show that the directivity of the integrated couplers is critical for establishing accurate power control over phase variations at high values of load mismatch. In addition, the presented module features fully integrated impedance matching at input and output ports with DC blocks. The entire module is plastic encapsulated on a 10 mm /spl times/ 10 mm laminate substrate. The module offers higher accuracy of Pout control, smaller size, lower bill-of-materials, and a shorter Pout calibration time to handset manufacturers. It is a very desirable RF PAM to handset designers because of its unique features. Under a low single supply voltage of 3.2 V, the PAM provides 35-dBm output power, 55% power-added efficiency (PAE) in the GSM900 band, and 33 dBm and 50% PAE in the DCS1800 band.     

A 3.3-V 21-Gb/s PRBS generator in AlGaAs/GaAs HBT technology

We present a pseudorandom bit sequence (PRBS) generator that outputs a 2⁷-1 bit pattern at rates up to 21 Gb/s. The circuit is implemented in a 40-GHz AlGaAs/GaAs heterojunction bipolar transistor (HBT) standard production process, operates from a single 3.3-V power supply, and consumes 1.1 W of power. We discuss variations of PRBS architecture and digital circuit topologies which exploit unique characteristics of AlGaAs/GaAs HBT devices. The work demonstrates the feasibility of using AlGaAs/GaAs HBT technology with low-voltage/low-power design techniques in complex high-speed circuits     

Gain/bandwidth programmable PA control loop for GSM/GPRS quad-band cellular handsets

The analog power amplifier (PA) control loop of a fully integrated GSM/GPRS quad-band transceiver, suitable for GSM 850, GSM 900, DCS 1800, PCS 1900, and GPRS class 12 applications is presented. The control loop is based on a fully integrated PA controller (PAC) which meets applicable 3GPP GSM/GPRS specifications. Both the gain and the bandwidth of the PA control loop are programmable as well as the standby voltage delivered to the external PA: these features, together with a high driving capability (8.4 mA at 2.5 V), make this solution capable of interfacing many combinations of PAs, couplers, and detectors. The PAC has been integrated in a BiCMOS SiGe 0.35-/spl mu/m process and measures 0.33 mm/sup 2/. The current consumption from a single 2.8-V power supply is 2.8 mA without load and 7.2 mA in the application using Hitachi's PF08109B PA.     

Linearised HBT MMIC power amplifier with partially RF coupled active bias circuit for W-CDMA portable terminals applications

A highly linear MMIC power amplifier for wideband code-division multiple-access (W-CDMA) portable terminals has been devised and implemented with a new integrated on-chip lineariser. The proposed lineariser, consisting of an InGaP/GaAs heterojunction bipolar transistor (HBT) active bias circuit partially coupled to RF input power together with a feedback capacitor, effectively improves gain compression with little insertion power loss and no additional die area. The optimised lineariser improves maximum output power (P1 dB) by 2 dB and adjacent channel leakage power ratio (ACLR) by 4 dB, and the implemented HBT MMIC power amplifier exhibits a P1 dB of 30 dBm, a power gain of 30 dB, a power added efficiency of 42% at the maximum output power under an operation voltage of 3.4 V, and an ACLR of -34 dBc at 27 dBm of output power.     

A 2.2-V operation, 2.4-GHz single-chip GaAs MMIC transceiver forwireless applications

A 2.2-V operation, single-chip GaAs MMIC transceiver has been successfully developed for 2.4-GHz-band wireless applications such as wireless local area network terminals. The chip is fabricated using a planar self-aligned gate field-effect transistor. To generate sufficient negative voltage for gate-biasing and to enhance switch power handling capability under a 2.2-V supply, a newly designed negative voltage generator with a voltage doubler (NVG-VD) and a switch control logic circuit are integrated on the chip, together with a power amplifier, a transmit/receive switch, and a low-noise amplifier. The NVG-VD is designed to produce both a 3.3-V positive step-up voltage and a -2.1-V negative voltage under 2.2 V in operation voltage. Biased with these outputs, the logic circuit accommodates high power outputs of over 25 dBm with a low operating voltage of 2.2 V in transmit mode, With a 2.45-GHz modulated signal based on IS-95 standards, a 21-dBm output power and a 33% efficiency are obtained at a ±1.25-MHz-offset adjacent channel power rejection of -45 dBc. In receive mode, a low-noise amplifier achieves a 1.8-dB noise figure and an 11-dB gain with a 3.0-mA current. This transceiver enables significant size and weight reductions in 2.4-GHz-band wireless application terminals     

A VSWR-protected silicon bipolar RF power amplifier with soft-slope power control

This paper presents the design and measured performance of a 1.8-GHz power amplifier featuring load mismatch protection and soft-slope power control. Load-mismatch-induced breakdown can be avoided by attenuating the RF power to the final stage during overvoltage conditions. This was accomplished by means of a feedback control system, which detects the peak voltage at the output collector node and clamps its value to a given threshold by varying the circuit gain. The issue of output power control has been addressed as well. To this end, a temperature-compensated bias network is proposed, which allows a moderate power control slope (dB/V) to be achieved by varying the circuit quiescent current according to an exponential law. The nonlinear power amplifier was fabricated using a low-cost silicon bipolar process with a 6.4-V breakdown voltage. It delivers a 33.5-dBm saturated output power with 46% maximum power-added efficiency and 36-dB gain at a nominal 3.5-V supply voltage. The device is able to tolerate a 10:1 load standing-wave ratio up to a 5.1-V supply voltage. Power control slope is lower than 80 dB/V between -15 dBm and the saturated output power level.     

1.5-W CW S-band GaInP/GaAs/GaInP double heterojunction bipolartransistor

We report the first large-signal power result from a double heterojunction bipolar transistor (DHBT) based on the GaInP/GaAs/GaInP material system. A CW output power of 1.51 W and a power added efficiency of 52% were achieved at 3 GHz. Because the GaInP collector has a relatively high bandgap of 1.89 eV, high DC bias voltage operation with collector bias extending to 20 V (for a 40-V swing) is possible in this GaInP/GaAs/GaInP DHBT. This high DC bias voltage operation represents a unique advantage over the more conventional AlGaAs/GaAs HBT     

Low 1/f noise characteristics of AlGaAs/GaAs heterojunction bipolartransistor with electrically abrupt emitter-base junction

It is shown that the use of an electrically abrupt emitter-base junction considerably reduces the 1/f noise of self-aligned AlGaAs/GaAs heterojunction bipolar transistor (HBT). Although this device does not have depleted AlGaAs ledge passivation layer, the low-frequency noise spectra show a very low 1/f noise corner frequency of less than 10 kHz, which is much lower than previously reported value of about 100 kHz from conventional passivated or unpassivated AlGaAs/GaAs HBT's. Except for a residual generation-recombination (g-r) noise component, the noise power is comparable to that of Si BJT. It is also found that the low-frequency noise power of the AlGaAs/GaAs HBT is proportional to the extrinsic GaAs base surface recombination current square. Unlike the other HBT's reported, the noise sources associated with interface state and emitter-base (E-B) space charge region recombination are not significant for our device     

用于SDH STM-64光接收机的GaAs HBT限幅放大器

采用2μm GaAs HBT工艺实现了10Gb/s的限幅放大器.整个系统包括一级输入缓冲、三级放大、一级用于驱动50Ω传输线的输出缓冲和失调电压补偿回路四个部分.采用双电源供电,正电源为3.3V,负电源为-2V,功耗为500mW.在输出电压幅度保持恒定(单端峰峰值300mV)的条件下,输入动态范围约为38dB.芯片面积为1.15×0.7mm².     

A single-chip GaAs RF transceiver for 1.9-GHz digital mobilecommunication systems

A 1.9-GHz single-chip GaAs RF transceiver has been successfully developed using a planar self-aligned gate FET suitable for low-cost and high-volume production. This IC includes a negative voltage generator for 3-V single voltage operation and a control logic circuit to control transmit and receive functions, together with RF front-end analog circuits-a power amplifier, an SPDT switch, two attenuators for transmit and receive modes, and a low-noise amplifier. The IC can deliver 22-dBm output power at 30% efficiency with 3-V single power supply, The new negative voltage generator operates with charge time of less than 200 ns, producing a low level of spurious outputs below -70 dBc through the power amplifier. The generator also suppresses gate-bias voltage deviations to within 0.05 V even when gate current of -144 μA flows. The IC incorporates a new interface circuit between the logic circuit and the switch which enables it to handle power outputs over 24 dBm with only an operating voltage of 3 V. This transceiver will be expected to enable size reductions in telephones for 1.9-GHz digital mobile communication systems     

DC to 40-GHz broad-band amplifiers using AlGaAs/GaAs HBT's

In this paper, we report two types of broad-band amplifiers implemented with AlGaAs/GaAs HBT's. One is a Darlington feedback amplifier and the other is a transimpedance amplifier. In the former circuit, a dc gain of 9.5 dB and a -3-dB bandwidth of 40 GHz were achieved. In the latter circuit, a transimpedance gain of 50 dBΩ and a -3-dB bandwidth of 27 GHz were achieved. To our best knowledge, they are the highest speed in each circuit configuration     

A 0.8-V 0.25-mW Current-Mirror OTA With 160-MHz GBW in 0.18-μm CMOS

A low-voltage low-power CMOS operational transconductance amplifier (OTA) with near rail-to-rail output swing is presented in this brief. The proposed circuit is based on the current-mirror OTA topology. In addition, several circuit techniques are adopted to enhance the voltage gain. Simulated from a 0.8-V supply voltage, the proposed OTA achieves a 62-dB dc gain and a gain-bandwidth product of 160 MHz while driving a 2-pF load. The OTA is designed in a 0.18-mum CMOS process. The power consumption is 0.25 mW including the common-mode feedback circuit     

Integrated AlGaAs/GaAs HBT high slew-rate and wide band operationalamplifier

We report the design, fabrication, and test results of a wide band and high slew-rate voltage-mode operational amplifier using AlGaAs/GaAs HBT's. To select higher carbon doping concentration is more effective in reducing base resistance, and lower emitter doping concentration possess a smaller input capacitance to improve the device speed. The HBT operational amplifier has provided 500 V/μs high slew-rate, only 8 ns setting time and about 2 GHz unity-gain frequency. Common mode rejection ratio (CMRR) values of this operational amplifier are in the order of 70 dB with a small DC input voltage offset 5 mV, and the open-loop gain is about 40 dB     

AlGaAs/GaAs HBT linearity characteristics

Communication systems require linear power amplifiers with high efficiency and very low intermodulation distortion. AlGaAs/GaAs heterojunction bipolar transistors (HBT's) were found to have very low intermodulation distortion in power operation. Two-tone tests were carried out on both common-emitter (CE) and common-base (CB) power HBT's. At 7 GHz, the CE HBT showed -20 dBc IM₃ (third-order intermodulation ratio) and 12% power added efficiency (PAE) per tone at the 1 dB gain compression point; IM₃ dropped to -30 dBc at 1.5 dB output power backoff. The CE HBT has lower intermodulation distortion than CB HBT. Load pull data were collected to aid the understanding of the intermodulation. Parameters of the Gummel-Poon model (as used in SPICE) were derived for HBT's based on dc data and small-signal S parameters at various bias points. The accuracy and validity of the model were confirmed by comparison to experimental two-tone results. SPICE predicts that the emitter and base resistances linearize the HBT and reduce the third-order intermodulation distortion. The excellent third-order intermodulation performance of the CE HBT makes it a very attractive choice for linear power amplifiers     

一种自适应线性化偏置的单片集成功率放大器

提出一种自适应线性化偏置的电路结构,通过调节控制电压改变偏置管的工作状态,提高功率放大电路的线性度,降低偏置电流对参考电压和环境温度的敏感度.利用双反馈环结构抑制输入阻抗随频率的变化,实现了宽带匹配,拓展了放大器的带宽.采用微波电路仿真软件AWR进行仿真,验证了带宽范围内的相位偏离度在2°以内.基于2μm InGaP/GaAs HBT工艺,设计了集成电路版图并成功流片.测试结果表明:在3.5V电压供电下,该放大器在1～2.5 GHz频带范围内,输入反射系数均在-10 dB以下,功率增益为23 dB,输出功率大于30 dBm,误差向量幅度在2.412 GHz时为.2.7％@24 dBm,最大功率附加效率达40％.     

ESD protection design considerations for InGaP/GaAs HBT RF power amplifiers

In order to design a robust electrostatic discharge (ESD) protected RF amplifier in InGaP/GaAs HBTs, a comprehensive assessment of device vulnerability to ESD events in both active transistors and passive components of the HBT technology is presented in this paper. The results include not only the intrinsic HBT's ESD robustness performance, but also its dependence on device layout, ballast resistor, and process. Acknowledging the ESD constraints imposed on InGaP/GaAs HBT technology, a 5.4-6.0-GHz power amplifier (PA) with a compact 2000 V/sub ESD/ (human body model) on-chip ESD protection circuit that has a low loading capacitance of less than 0.1 pF and that does not degrade RF and output power performance is developed for wireless local area network application. A diode triggered Darlington pair is implemented as the ESD protection circuit instead of the traditional diode string. Its operation principle, ESD protection performance, and PA performance are also illustrated in this paper.     

A 5-10 GHz octave-band AlGaAs/GaAs HBT-Schottky diodedown-converter MMIC

The authors describe an AlGaAs/GaAs heterojunction bipolar transistor (HBT) X-band down-converter monolithic microwave integrated circuit (MMIC) which integrates a double double-balanced Schottky mixer and five stages of HBT amplification to achieve greater than 30 dB conversion gain over an RF bandwidth from 5 to 10 GHz. In addition, an output IP3 as high as +15 dBm has been achieved. The Schottky diodes are constructed from the existing N^$collector and N⁺ subcollector layers of the HBT molecular beam epitaxy (MBE) device structure. A novel HBT amplifier topology employing active feedback which provides wide bandwidth in a compact area is used for the RF, LO, and IF amplifier stages. The complete down-converter MMIC is realized in a 3.6×3.4 mm² area, is self-biased through a 6 V supply, and consumes 530 mW. This MMIC represents the highest complexity X-band down-converter MMIC demonstrated using GaAs HBT-Schottky diode technology     

High-efficiency Ku-band HBT MMIC power amplifier

A Ku-band monolithic HBT power amplifier was developed using a metal-organic chemical vapor deposition (MOCVD)-grown AlGaAs/GaAs heterojunction bipolar transistor (HBT) operating in common-emitter mode. At a 7.5 V collector bias, the amplifier produced 0.5 W CW output power with 5.0 dB gain and 42% power-added efficiency in the 15-16 GHz band. When operated at a single frequency (15 GHz), 0.66 W CW output power and 5.2 dB of gain were achieved with 43% PAE     

一种GaAs HBT微波功率放大器的设计

介绍了C波段宽带固态功率放大器的设计方法和实际测试结果。该放大器用于某雷达发射组件推动级,采用GaAs HBT器件,宽带匹配电路、直流偏置、负反馈设计。根据负载牵引分析,运用微波仿真软件对功率管的输入、输出阻抗匹配电路及其偏置电路进行优化仿真设计,增加电源控制电路保证可靠性,研制出了符合整机指标要求的放大器。