Interfacing the VCA8617 with High-Speed ADCs
The VCA8617 is an 8-channel variable gain amplifier ideally suited for portable and mid-range ultrasound applications. Each channel consists of a Low Noise Amplifier (LNA) and a Variable Gain Amplifier (VGA). The VGA contains two parts: a voltage-controlled attenuator and a programmable gain amplifier. The PGA output feeds directly into an integrated 3-pole low-pass Butterworth filter, which prevents the need for an external filter between the VCA8617 and the analog-to-digital converter (ADC). This application report discusses different methods of interfacing the VCA8617 with various ADCs, particularly the ADS527x and ADS512x families.