Amplifier is suitable for cable set top boxes, cable modems, xDSL modems and xDSL central office line cards. It offers very low noise, high performance amplifiers that are widely deployed as xDSL receivers.

The basic gain function is linear-in-dB and is controlled by the voltage applied to pin gain. The nominal gain range spans from 0 dB to 80 dB for control voltages between 0.1V to 1.1V with a slope of 12.5mV/dB. The nominal gain range can be shifted up or down via direct access to Pin INPD and Pin INMD, the current inputs of the VGA. For example, driving the INPD and INMD pins with 50ohms resistors shifts the gain range up by 20dB, that is, 20dB to 100dB, and lowers the input referred noise of the device. Additionally, the gain slope can be inverted via logic pin mode.

It includes additional circuit blocks to enable input offset correction and automatic gain control (AGC). DC offset voltages are removed by the offset correction circuit, which behaves like a high-pass filter whose corner is set with an external capacitor. The AGC function varies the gain of the AD8338 to maintain a constant RMS output voltage. An externally applied voltage to Pin VAGC with respect to the voltage at Pin VREF sets the output RMS amplitude. A capacitor from Pin DETO to ground sets the response time of the AGC circuit.

It offers additional versatility by providing access to the internal summing nodes of the VGA core and the output amplifiers. With the addition of a few external passive components, users can customize the gain, bandwidth, input impedance, and noise profile of the part to fit their application.

It uses a single supply voltage of 3V to 5V and is very power efficient, consuming as little as 3 mA quiescent current at mid gain. It is available in a 3mm × 3mm, RoHS compliant, 16-lead LFCSP and is specified over the industrial temperature range.