VCA8617,pdf(Eight-Channel Vari

The VCA8617 is an 8-channel variable gain amplifier ideally suited to portable ultrasound applications. Excellent dynamic performance enables use in low-power, high-performance portable applications. Each channel consists of a 20dB gain Low-Noise pre-Amplifier (LNA) and a Variable Gain Amplifier (VGA). The differential outputs of the LNA can be switched through the 8x10 cross-point switch, which is programmable through the serial interface input port.

The output of the LNA is fed directly into the VGA stage. The VGA consists of two parts, a Voltage-Controlled Attenuator (VCA) and a Programmable Gain Amplifier (PGA). The gain and gain range of the PGA can be digitally configured separately. The gain of the PGA can vary between four discrete settings of 25dB, 30dB, 35dB, and 40dB.