GENERAL DESCRIPTION

The AD8338 is a variable gain amplifier (VGA) for applications that require a fully differential signal path, low power, low noise, and a well-defined gain over frequencies from LF to 18 MHz. The device can also operate using single-ended sources if required. The basic gain function is linear-in-dB with a nominal gain range of 0 dB to 80 dB; the nominal gain range corresponds to a control voltage on the GAIN pin of 0.1 V to 1.1 V. The gain range can be adjusted up or down via direct access to the internal summing nodes at the INPD and INMD pins. For example, if a 47 Ω resistor is applied to the INPD and INMD pins, a gain range of 20 dB to 100 dB is set with an input referred noise level of 1.5 nV√Hz.

FEATURES

Voltage controlled gain range of 0 dB to 80 dB

3 mA supply current at gain of 40 dB

Low frequency (LF) to 18 MHz operation

Supply range: 3.0 V to 5.0 V

Adjustable gain range

Low noise: 4.5 nV/√Hz

Fully differential signal path

Offset correction (offset null) feature

Adjustable bandwidth

Internal 1.5 V reference

16-lead LFCSP

Automatic gain control feature

Wide gain range for high dynamic range signals

APPLICATIONS

Front end for inductive telemetry systems

Ultrasonic signal receivers

RF baseband signal conditioning