GENERAL DESCRIPTION
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 200 kSPS SAR ADC. An internal low ppm reference is provided to drive both the 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 a high voltage DMOS process for a high voltage compliance, 48 V on the current-sense inputs, and up to 15 V DAC output voltage.
The part is ideal for bias current control of the power transistors used in power amplifiers employed in CDMA, GSM, EDGE, and UMTS cellular base stations.
The DACs provide digital control with 1.2 mV resolution to control the bias currents of the power transistors. They can also be used to provide control voltages for variable gain amplifiers or impedance match networks in the main signal chain. Thermal diode based temperature sensors are incorporated to compensate for temperature effects. The ADC monitors the high-side current and temperature. All this functionality is provided in a 56-lead LFCSP package and a 64-lead TQFP package operating over a temperature range of −40°C to +105°C.

FEATURES
  4-channel 12-bit DAC
     Guaranteed monotonic
     10 μs settling time
     10 mA sink and source capability
     Offset in for range adjustment
     Output span: 5 V in 0 to 15 V range
  9-channel, 12-bit ADC
     200 kSPS throughput
     Input range: 0 to VREF, 0 to 2 VREF
     Differential/single-ended
     Limit registers per channel
  2 high-side current sense
     48 V max operation
     ±1% FS accuracy
     ±200 mV input range
  3-channel temperature sensor
     Diode temperature measurement
     ±2°C accuracy
     Measurement range: −10°C to +90°C
  Internal 2.5 V reference
  I2C®-compatible serial interface
  Temperature range: −40°C to +105°C
  Alert function
  Package type: LFCSP-56, TQFP-64

APPLICATIONS
  Cellular base station (GSM, EDGE, UMTS, CDMA)
  Point-to-multipoint and other RF transmission systems
  12 V, 24 V, 48 V automotive applications
  Industrial control