12-Bit Power Amplifier Current Controller with ADC, DACs, Temperature and Current Sensors

The AD7293 is a PA drain current controller containing functionality for general-purpose monitoring and control of current, voltage, and temperature, integrated into a single chip solution with an SPI-compatible interface.

The device features a 4-channel, 12-bit successive approximation register (SAR) ADC, eight 12-bit DACs (four bipolar and four unipolar with output ranges that can be configured to shut down under external pin control), a ±1.25°C accurate internal temperature sensor, and eight general-purpose input/output (GPIO) pins.

The device also includes limit registers for alert functions and four high-side current sense amplifiers to measure current across external shunt resistors. These amplifiers can be optionally set to operate as part of four independent closed-loop drain current controllers.

A high accuracy 2.5 V internal reference is provided to drive the DACs and the ADC. The 12-bit ADC monitors and digitizes the internal temperature sensor, and two inputs are included for the external diode temperature sensors.

Product Highlights

* Four independent closed-loop drain current controllers.

* Built-in monitoring, sequencing, and alert features.

* Compatible with both depletion mode and enhancement

mode power amplifiers.

Applications

* GaN and GaAs power amplifier monitoring and controls

* Base station power amplifiers

* General-purpose system monitoring and controls

* 4 closed-loop power amplifier (PA) drain current controllers

* Built-in PA protection, sequencing, and alert features

* Compatible with both depletion mode and enhancement mode power amplifiers

* Highly integrated

* 4 uncommitted 12-bit analog-to-digital converter (ADC) inputs

* ±0.5 LSB typical integral nonlinearity (INL)

* Eight 12-bit voltage digital-to-analog converters (DACs)

* 1.3 μs maximum settling

* 4 high-side current sense amplifiers, ±0.1% gain error

* 2 external temperature sensor inputs, ±1.1°C accuracy

* Internal temperature sensor, ±1.25°C accuracy

* 2.5 V on-chip reference

* Flexible monitoring and control ranges

* ADC input ranges: 0 V to 1.25 V, 0 V to 2.5 V, and 0 V to 5 V

* Bipolar DAC ranges: 0 V to +5 V, −4 V to +1 V, and −5 V to 0 V

* Bipolar DAC reset and clamping relative to VCLAMPx voltage

* Unipolar DAC ranges: 0 V to 5 V, 2.5 V to 7.5 V, and 5 V to 10 V

* Current sense gain: 6.25, 12.5, 25, 50, 100, and more

* Adjustable closed-loop setpoint ramp time