Analog Devices has extended its portfolio of RFICs with a new analog-control, variable-gain amplifier (VGA) that offers high linearity over a broad frequency range for wireless infrastructure applications, such as cellular base station transceivers. The AD8368 is optimized to maintain dynamic range of base station transceivers, ensuring that weak and strong incoming call signals are effectively handled and maintained. In addition, the AD8368 simplifies and reduces the number of external components required by integrating an accurate root-mean-square (rms) power detector on chip, which enables a complete automatic gain control (AGC) loop within a small 4 mm x 4 mm package.

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The device is capable of sustaining high linearity (OIP3 of 34 dBm at 70 MHz) at the highest intermediate frequencies (IFs), allowing it to be used in all wireless standards, including 2G and 3G, as well as emerging broadband wireless standards such as 802.16 (WiMAX). The 380-MHz frequency range of the AD8368 allows the device to be used in both receive and transmit paths within any wireless infrastructure standard where the use of one or more AGC loops optimizes the base station dynamic range or allows the designer to add additional gain for optimal signal dynamic range and sensitivity.

The linear-in-dB gain control conformance and flatness of the device can be attributed to ADI’s X-AMP architecture, a technique for implementing high-performance, continuous variable gain control. The device provides continuous 34-dB linear-in-dB gain control from –12 dB to + 22 dB. With a 3-dB bandwidth of 800 MHz independent of gain setting, a single-ended input and output drive, and exceptional linearity over the full operating range, the device is suited for use in GSM, CDMA2000, W-CDMA, and TD SCDMA cellular base stations. Operating from a single supply voltage of 4.5 V to 5.5 V, the device consumes only 54 mA of current.

The AD8368 is sampling now with full production scheduled for April 2006. The device is priced at $4.55 per unit in 1000-piece quantities and is available in a 24-pin lead frame chip scale package.