SLAS986D November 2014 – February 2018 AMC7836
The AMC7836 device is a highly integrated, low-power, analog monitoring and control solution that includes a 21-channel (12-bit) ADC, 16-channel (12-bit) DACs, eight GPIO, and a local temperature sensor. Although the device can be used in many different closed-loop systems, including industrial control and test and measurement, the device is largely used as a power amplifier controller in multi-channel RF communication applications.
Power amplifiers (PAs) include transistor technologies that are extremely temperature sensitive, and require DC biasing circuits to optimize RF performance, power efficiency, and stability. The AMC7836 device provides 16 DAC channels which can be used to adjust the power amplifier bias points in response to temperature changes. The device also includes an internal local temperature sensor, and 21 ADC channels for general-purpose monitoring.
Current and temperature sensing are typically implemented in power amplifier controller applications. PA drain current sensing is implemented by measuring the differential voltage drop across a shunt resistor. Temperature variations during PA operation can be detected either through the AMC7836 internal temperature sensor or through remote temperature ICs or thermistors configured to interface with the ADC analog inputs available in the device. Figure 115 shows the block diagram for these different systems.