Application of high performance operational amplifier SC7301 in multimedia broadcasting system

The main function of the amplifier in the multimedia broadcasting system is to amplify the weak audio input voltage signal generated by various means and then send it to each user's device. The amplifier is mainly composed of two categories: pre-amplifier and power amplifier. Some amplifiers combine these two parts in one device, while others separate these two parts into two devices. The pre-amplifier is to initially amplify the input weak audio signal so that the amplified signal can meet the input level requirements of the power amplifier. The power amplifier is to further amplify the signal obtained by the pre-amplifier to achieve the power required on the wired broadcast line.

The power amplifier is one of the important equipment in the broadcasting system, and the output power can range from a few watts to several kilowatts. In the design, the corresponding grade and specification of the product are selected according to the sound quality standard and required capacity of the sound reinforcement system. There are many amplifier products at home and abroad, but basically they have formed a series, which can meet the requirements of sound quality and capacity in various environments. This article introduces the use of a broadband current feedback operational amplifier core SC7301.

The SC7301 is ideal for high-speed pulse applications. It can achieve a maximum slew rate greater than 2500V/μs, a settling time of less than 25ns to 0.1% for a 2V step, and a settling time of less than 65ns to 0.01% for a 10V step. The SC7301 is ideal for use as an ADC or DAC buffer in data acquisition systems because it has low distortion and wide unity-gain bandwidth up to 10MHz. The 3dB bandwidth is 120MHz, the gain is +2, and the differential gain and phase are 0.01% and 0.01° (RL=150Ω), making the SC7301 an excellent choice for video/audio systems.

The design features of SC7301 are: 35MHz bandwidth (G=+2); 0.1dB gain flatness specification; small differential gain and phase error. The chip can achieve this performance under low power supply and low current, whether driving one or two 75Ω cables. In addition, the rated power supply voltage range of SC7301 is ±5V to ±18.