Variable gain amplifier

Analog Devices has introduced a new analog-control variable-gain amplifier (VGA) that offers exceptional linearity over a broad frequency range for wireless infrastructure applications, such as cellular base station radio transceivers.

The AD8368 is optimised to maintain dynamic range of base station radio transceivers, ensuring that both 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 × 4 mm IC package.

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 optimises the base station dynamic range or allows the designer to add additional gain for optimal signal dynamic range and sensitivity.

The AD8368 is sampling now with full production scheduled for April 2006. The device is priced at $4.55 per unit in 1,000-piece quantities, is available in a 24-pin LFCSP (lead frame chip scale package), and is specified over an operating temperature range of –40°C to +85°C.