AMC7834 Datasheet, PDF (77/93 Pages) Texas Instruments – AMC7834 12-Bit Integrated Power-Amplifier Monitor and Control System with Temperature, Current and Voltage Supervision Capabilities

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8 Application and Implementation
AMC7834
SLAS972B – NOVEMBER 2014 – REVISED MARCH 2016
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The AMC7834 device is a highly integrated, low-power, analog monitoring and control solution that includes one
multi-channel 12-bit ADC, eight 12-bit DACs, four high-side current-sense amplifiers and temperature sensing
capabilities. The AMC7834 typical application is power amplifier biasing in wireless base stations, however its
high level integration make it a good solution for many different systems ranging from industrial control sytems to
test-and-measurement units.
The power amplifiers (PAs) used in wireless infrastructure include transistor technologies that are extremely
temperature sensitive, and require DC biasing circuits to optimize RF performance, power efficiency, and
stability. The AMC7834 device provides eight DAC channels that can be used to bias the inputs of the power
amplifiers. The device also includes two remote temperature sensing interfaces, one internal local temperature
sensor, four high-side current-sensing channels, and four ADC channels for general-purpose monitoring.
Current sensing and temperature sensing are the two main monitoring schemes for PA bias compensation. The
PA drain current is monitored by measuring the differential voltage drop accross a shunt resistor. The AMC7834
internal local-temperature sensor and two remote-sensor driver inputs can be used to detect temperature
variations during PA operation. Figure 103 shows the circuit diagram of this system.
AMC7834
Analog Inputs
GPIO
CS
Current Sense
ADC
CS
Bipolar
Analog Outputs
Unipolar
Analog Outputs
Local
Temperature
Remote
Temperature
DAC
AUX
DAC
PA Drain Voltage
R_(SENSE)
SENSE1+
VSENSE Current Sensing
SENSE1±
RF Out
D1+
Temperature Sensing
D1±
Drain
Gate
Source
Power Amplifier
RF In
Figure 103. AMC7834 Example PA Bias System
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