The VCA8500 is an 8-channel variable gain amplifier consisting of a low-noise pre-amplifier (LNP) and a variable-gain amplifier (VGA). This combination, along with the device features, makes it ideal for a variety of ultrasound systems.
The LNP gain is fixed at 20dB, and has excellent noise and signal handling characteristics. The gain of the voltage-controlled attenuator can vary over a 46dB range with a 0V to 1.2V control voltage common to all channels of the VCA8500.
The post-gain amplifier (PGA) can be programmed for four gain settings: 20dB, 25dB, 27dB, or 30dB gain. As a means to improve system overload recovery time, the VCA8500 provides an internal clamping function. The PGA settings as well the clamp levels are controlled through the serial interface.
The VCA8500 is built on TI's BiCOM process and is available in a small QFN-64 PowerPAD package.