AD602

FEATURES 2 channels with independent gain control Linear in dB gain response 2 gain ranges AD600: 0 dB to 40 dB AD602: –10 dB to +30 dB Accurate absolute gain: ±0.3 dB Low input noise: 1.4 nV/√Hz Low distortion: −60 dBc THD at ±1 V output High bandwidth: dc to 35 MHz (−3 dB) Stable group delay: ±2 ns Low power: 125 mW (maximum) per amplifier Signal gating function for each amplifier Drive high speed ADCs MIL-STD-883-compliant and DESC versions available APPLICATIONS Ultrasound and sonar time-gain controls High performance audio and RF AGC systems Signal measurement GENERAL DESCRIPTION The AD600/AD6021 dual-channel, low noise, variable gain amplifiers are optimized for use in ultrasound imaging systems but are applicable to any application requiring precise gain, low noise and distortion, and wide bandwidth. Each independent channel provides a gain of 0 dB to +40 dB in the AD600 and −10 dB to +30 dB in the AD602. The lower gain of the AD602 results in an improved signal-to-noise ratio (SNR) at the output. However, both products have the same 1.4 nV/√Hz input noise spectral density. The decibel gain is directly proportional to the control voltage, accurately calibrated, and supply and temperature stable. To achieve the difficult performance objectives, a proprietary circuit form, the X-AMP®, was developed. Each channel of the X-AMP comprises a variable attenuator of 0 dB to −42.14 dB followed by a high speed fixed gain amplifier. In this way, the amplifier never has to cope wit...