Datasheet AD7294-2 (Analog Devices)

12-Bit Monitor and Control System with Multichannel ADC, DACs, Temperature Sensor, and Current Sense Data Sheet AD7294-2 FEATURES APPLICATIONS 12-bit SAR ADC with 3 μs conversion time Cellular base stations 4 uncommitted analog inputs GSM, EDGE, UMTS, CDMA, TD-SCDMA, W-CDMA, WiMAX Differential/single-ended Point-to-multipoint and other RF transmission systems VREF, 2 × VREF input ranges 12 V, 24 V, 48 V automotive applications 2 high-side current sense inputs Industrial controls 5 V to 59.4 V operating range GENERAL DESCRIPTION 0.75% maximum gain error ±200 mV input range
The AD7294-2 contains al the functions that are required for
2 external diode temperature sensor inputs
general-purpose monitoring and control of current, voltage,
−55°C to +150°C measurement range
and temperature, integrated into a single-chip solution. The part
±2°C accuracy
includes low voltage (±200 mV) analog input sense amplifiers
Series resistance cancellation
for current monitoring across shunt resistors, temperature sense
1 internal temperature sensor: ±2°C accuracy
inputs, and four uncommitted analog input channels multiplexed
Built-in monitoring features
into a SAR analog-to-digital converter (ADC) with a 3 μs
Minimum/maximum recorder for each channel
conversion time. A high accuracy internal reference is provided
Programmable alert thresholds
to drive both the digital-to-analog converters (DACs) and the
Programmable hysteresis
ADC. Four 12-bit DACs provide the outputs for voltage control.
Four 12-bit, monotonic, 15 V DACs
The AD7294-2 also includes limit registers for alarm functions.
5 V span, 0 V to 10 V offset
The part is designed for high voltage compliance: 59.4 V on the
8 μs settling time
current sense inputs and up to a 15 V DAC output voltage.
10 mA sink and source capability
The AD7294-2 is a highly integrated solution that offers al the
Power-on reset (POR) to 0 V
functionality necessary for precise control of the power amplifier
Internal 2.5 V reference
in cel ular base station applications. In these types of applications,
2-wire, fast mode I2C interface
the DACs provide 12-bit resolution to control the bias currents
Temperature range: −40°C to +105°C
of the power transistors. Thermal diode-based temperature sensors
Package type: 64-lead TQFP
are incorporated to compensate for temperature effects. The ADC
Pin compatible with the AD7294
monitors the high-side current and temperature. This functionality is provided in a 64-lead TQFP, which operates over a temperature range of −40°C to +105°C.
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Document Outline Features Applications General Description Table of Contents Revision History Functional Block Diagram Specifications DAC Specifications ADC Specifications General Specifications Timing Characteristics I2C Serial Interface Timing and Circuit Diagrams Absolute Maximum Ratings Thermal Resistance ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Terminology DAC Terminology ADC Terminology Theory of Operation ADC Overview ADC Transfer Functions Analog Inputs Single-Ended Mode Differential Mode Driving Differential Inputs Using an Op Amp Pair Pseudo Differential Mode Current Sensor Choosing RSENSE Current Sense Filtering Kelvin Sense Resistor Connection Analog Comparator Loop Temperature Sensor Remote Sensing Diode Ideality Factor Base Emitter Voltage hFE Variation Series Resistance Cancellation DAC Operation Resistor String Output Amplifiers ADC and DAC Reference VDRIVE Feature Register Settings Address Pointer Register Command Register ADC Result Register ADC Channel Allocation TSENSE1 and TSENSE2 Result Registers TSENSEINT Result Register Temperature Value Format DACA, DACB, DACC, and DACD Value Registers Alert Status Register A, Alert Status Register B, and Alert Status Register C Channel Sequence Register Configuration Register Sample Delay and Bit Trial Delay Power-Down Register DATALOW and DATAHIGH Registers VIN0 to VIN3 Channels TSENSE1, TSENSE2, and TSENSEINT Channels Hysteresis Registers Remote Channel TSENSE1 and TSENSE2 Offset Registers I2C Interface General I2C Timing Serial Bus Address Byte Interface Protocol Writing a Single Byte of Data to an 8-Bit Register Writing Two Bytes of Data to a 16-Bit Register Writing to Multiple Registers Reading Data from an 8-Bit Register Reading Two Bytes of Data from a 16-Bit Register Modes of Operation Command Mode Autocycle Mode Alerts and Limits Theory ALERT_FLAG Bit Alert Status Registers DATALOW and DATAHIGH Monitoring Features Hysteresis Using the Limit Registers to Store Minimum/Maximum Conversion Results Applications Information Base Station Power Amplifier Monitor and Control Gain Control of Power Amplifier Outline Dimensions Ordering Guide