The AD7294 contains all the functions required for general-purpose monitoring and control of current, voltage, and temperature integrated into a single-chip solution. The part includes low voltage (±200 mV) analog input sense amplifiers for current monitoring across shunt resistors, temperature sense inputs, and four uncommitted analog input channels multiplexed into a SAR analog-to-digital converter (ADC) with a 3 μs conver-sion time. A high accuracy internal reference is provided to drive both the digital-to-analog converter (DAC) and ADC. Four 12-bit DACs provide the outputs for voltage control. The AD7294 also includes limit registers for alarm functions. The part is designed on Analog Devices, Inc., high voltage DMOS process for high voltage compliance, 59.4 V on the current sense inputs, and up to a 15 V DAC output voltage.
The AD7294 is a highly integrated solution that offers all the functionality necessary for precise control of the power amplifier in cellular base station applications. In these types of applications, the DACs provide 12-bit resolution to control the bias currents of the power transistors. Thermal diode-based temperature sensors are incorporated to compensate for temperature effects. The ADC monitors the high-side current and temperature. All this func-tionality is provided in a 64-lead TQFP operating over a temperature range of ?40°C to +105°C.