PA04 datasheet

PA04 APEX U.S. produced a high-current power amplifier, which has high operating voltage, output current, high slew rate, and low distortion. By combining with the pin of the device characteristics and typical applications, introduces the working principle of PA04 and selected peripheral devices should pay attention to some problems. PA04 for the high current power amplifier. Because of its relatively large output current, which in ordinary settings, and use many different power amplifiers. Here on the working principle of PA04 and its external circuit in the application of issues needing attention and introduced the principles to do something. 2.1-limiting and current limiting resistor PA04 pin 10 and pin 11 for the current feedback input connection circuit shown in Figure 2, the figure, the pin 11 and the amplifier output directly connected to pin 10 and limiting resistor connection. The benefits of such connections can bypass any other parasitic resistance. Limiting resistor must be connected to the position shown in Figure 2. Its size can be calculated by: RCL = 0.76/ILIMIT 2.2 Sleep works Work in sleep mode, PA04 pin 12 and pin 9 connected, the internal amplifier to stop working, then the amplifier will be in hibernation. Sleeping approximately 3mA of current flow through the pin 12. Sleep mode when not in use, should pin 12 floating. There are many dormant circuit, shown in Figure 3 is a sleep circuit. Left logic circuits for the differential mode signal input signal using the transistor conduction and cut-off characteristics can be realized pin 9 and pin 12 is disconnected or connection control. 2.3 Enhanced input PA04 pin 5 and pin 9 to enhance the voltage input (VBOOST) feet, with increased voltage input pin of amplifier For most of the work in the high pressure with little in the high current state. Therefore, + VBOOST pin (pin 9) and-VBOOST pin (pin 5) is generally connected to the amplifier's small signal circuit, + Vs (pin 8) and-Vs (pin 6) was connected to a large current output. When the required output voltage is close to the power supply voltage (ie, lowering the pressure drop), can be applied in VBOOST pin 5V voltage (VBOOST = VS +5) to make the small-signal driving the output transistor saturation At the same time it can also improve the output voltage fluctuations. If you need to improve the output voltage fluctuations, + VBOOST pin and + Vs pin,-VBOOST pin to pin and-Vs are connected together, and certainly not VBOOST pin voltage lower than the Vs pin voltage. VBOOST = VS and VBOOST = VS +5 floating when the output voltage and output current relationship shown in Figure 4.