ANADIGICS Announces High Performance MMIC Solutions For Cellular And PCS Base Station Applications

ANADIGICS, Inc., a leading supplier of gallium arsenide (GaAs) integrated circuits for wireless communications, today unveiled a series of GaAs MMICs which offer high performance, cost-effective solutions for designers of cellular and PCS infrastructure applications.

The company has unveiled three high power, high gain power amplifiers, the AWT921, developed for base station applications in the 900 MHz frequency range, the AWT1921, developed for operation in the 1.6 GHz satellite communications band, and the AWT1922, designed for 1.9 GHz PCS and GSM base station applications. Also available is the AWR0901, a high linearity GaAs MMIC receiver intended for cellular base station applications in the 800 MHz to 1 GHz frequency range.

All four components are designed and characterized for high reliability in end use base station environments which require robust, high performance MMIC solutions. Given that base station are becoming smaller and designers need components that will reduce board space through a high level of integration and packaging technology, these components also feature high levels of integration in small surface mount packages.

The AWT921 is a 3 stage integrated power amplifier designed to operate at 8.5 volts in the 900 MHz frequency range. It has been specifically designed for multi-carrier, microcell base station and local loop applications, which require high gain and output intercept point. It has been designed to work in all popular wireless cellular formats, including GSM, CDMA, TDMA, and AMPS.

The AWT921 achieves an output power of +39 dBm with an associated gain of 28 dB. This power amplifier exhibits excellent linearity at a 5 watt (+37 -dBm) level.

This part also features on-chip biasing circuitry. User manufacturing costs are reduced because these internal circuits require only fixed bias voltages, eliminating the need for in-line adjustments or tuning.

"Only nominal +/-10% positive and negative reference voltages need to be supplied to this circuit to bias the amplifier to its targeted levels," stated David Osika, Manager, Advanced Technologies. "The significance of this amplifier is that in production, no sorting of components will be needed or bias adjustments will be required allowing high volume manufacturing techniques to be applied."

Also achievable is optimum load tuning for frequency response and transfer characteristics with an off-chip inductance-capacitance matching circuit. The output matching network can be realized with the proper placement of a shunt capacitor on the output transmission line.

"GaAs MMIC power amplifiers are currently used in handset or terminal designs up to the 3 watt level and have proven to be a cost-effective solution," Osika added. "The same MMIC design techniques can be applied to fixed installations to provide solutions for driver sections in macro base stations and can also be used as the final amplifier in micro cells."

Outdoor installation of base stations mounted in equatorial regions requires that components need to sustain operation of 85°C case temperatures. The AWT921 provides high component reliability under continuous operation, achieving greater than 106 Hrs MTTF (Mean-Time-To-Failure).

Also being announced are two four-stage monolithic power amplifiers specifically designed for higher frequency operation. The AWT1922 has been designed for PCS 1900 & DCS 1800 multi-carrier base stations applications, while the AWT1921 has been developed for operation in the satellite communications band from 1610-1626.5 MHz. These power amplifiers can be designed into portable or fixed access satellite units, which transmit signals to the orbiting satellite. The AWT1921 can also be used for TDMA and CDMA applications, which require high linearity to preserve modulation information.

The AWT1921 provides greater than +35 dBm of linear power with 28 dB of gain. Typical output power is +39 dBm with 9 volt operation. The AWT1922 offers typical power added efficiency of 35% at Pout of +39 dBm with 28 dB gain.

The AWT1921 and AWT1922 provide an on chip active bias circuit that enables +/-10% voltage settings. "These power amplifiers allow off chip resistive elements to be chosen at design time so designers can optimize the tradeoff between various characteristics such as linearity and efficiency," Osika said. "As building blocks, the power amplifiers can be used at the final stage and simplify the design of the transmit RF amplifier chain."

The on-chip matching elements have sufficient bandwidths allowing the power amplifiers to operate in applications from 1000-2000 MHz. The recommended off chip output matching circuit consists of a single L-C network achieved by using a length of transmission line along with a shunt capacitor. Optimum in- band performance is achieved with external high Q elements, which limits the operational bandwidth. Board level RF choke elements and bypass capacitors have been selected for obtaining good linearity while achieving high power and efficiency.

The AWR0901, a high linearity wireless receiver IC, performs the receiving function in cellular infrastructure applications. A fully monolithic downconverter, the AWR0901 is a 5 volt GaAs receiver that operates in the 824 to 850 MHz frequency range and covers wireless standards worldwide. It is specifically suited for applications where an external oscillator is required. Featuring a high dynamic range balanced mixer, this new receiver provides better than 13 dB conversion gain, noise figures of less than 3 dB over any band within the 800 MHz to 1 GHz range, Input 3rd Order Intercept (IIP3) of more than +10, and Half IF IIP performance of +40 dBm.

"The Half IF performance of the AWR0901 gives designers more flexibility in performing tradeoffs between front-end duplexers and back-end selectivity," said John van Saders, Director, Advanced Circuit Products. "The high dynamic range of this integrated receiver is ideal for operation in crowded environments." The AWR0901 also can be utilized for "Radio in the Local Loop" applications. There are many areas where a good telephone infrastructure is non-existent. In some remote areas, it is difficult and cost-prohibitive to lay cables and build up that infrastructure. "In some cases, with a radio solution, geographical barriers can become overcome enabling more remote areas to be reached," added van Saders.

The AWT921, AWT1921 and AWT1922 are packaged in wide body 28-pin, thermally enhanced SSOP packages. The AWR0901 is available in a 16-pin SOIC package. The AWT921, AWT1921, AWT1922 and AWR0901 are manufactured using ANADIGICS' proven high volume GaAs MESFET technology, resulting in a low cost and space efficient solution compared to hybrid models and discrete designs. They are manufactured in the company's state-of-the-art ISO 9001 certified facility in New Jersey, and are 100% tested at DC and RF before shipping to maximize reliability.

The AWR0901 is available at $3.50 in quantities of 100,000. The AWT921 is available at $20.00 in quantities of 100,000. The AWT1921 and AWT1922 are available at $25.00 in quantities of 100,000.