Texas Instruments INA237/INA237-Q1 Current/Voltage/Power Monitors

Texas Instruments INA237/INA237-Q1 Current/Voltage/Power Monitors are ultra-precise digital power monitors with a 16-bit delta-sigma (ΔΣ) ADC specifically designed for current-sensing applications. The device can measure a full-scale differential input of ±163.84mV or ±40.96mV across a resistive shunt sense element with common-mode voltage support from –0.3V to +85V. The INA237/INA237-Q1 reports current, bus voltage, temperature, and power, all while performing the needed calculations in the background. The integrated temperature sensor is ±1°C accurate for die temperature measurement and is useful in monitoring the system’s ambient temperature.

The low offset and gain drift design of the Texas Instruments INA237/INA237-Q1 allows the device to be used in precise systems that do not undergo multi-temperature calibration during manufacturing. Further, the very low offset voltage and noise allow for use in A to kA sensing applications and provide a wide dynamic range without significant power dissipation losses on the sensing shunt element. The low input bias current of the device permits the use of larger current-sense resistors, thus providing accurate current measurements in the micro-amp range. The device allows for selectable ADC conversion times from 50µs to 4.12ms as well as sample averaging from 1x to 1024x, which further helps reduce the noise of the measured data.

Features

  • High-resolution, 16-bit delta-sigma ADC
  • Current monitoring accuracy
    • ±50µV (maximum) offset voltage
    • ±0.02µV/°C (maximum) offset drift
    • ±0.3% (maximum) gain error
    • ±50ppm/°C (maximum) gain error drift
    • 120dB (minimum) common mode rejection
  • Power monitoring accuracy
    • 1.6% full scale, –40°C to +125°C (maximum)
  • 75µs fast alert response
  • –0.3V to +85V wide common-mode range
  • 0V to 85V bus voltage sense input
  • ±163.84mV / ±40.96mV shunt full-scale differential range
  • 2.5nA (maximum) input bias current
  • ±1°C (maximum at 25°C) temperature sensor
  • Programmable conversion time and averaging
  • 2.94MHz high-speed I2C interface with 16 pin-selectable addresses
  • Operates from a 2.7V to 5.5V supply
    • 640µA (typical) operational current
    • 5µA (maximum) shutdown current

Applications

  • DC/DC converters and power inverters
  • Industrial battery packs
  • Power-over-Ethernet (PoE)
  • Telecom equipment
  • Enterprise servers

Functional Block Diagram

Block Diagram - Texas Instruments INA237/INA237-Q1 Current/Voltage/Power Monitors

Texas Instruments INA237/INA237-Q1 Current/Voltage/Power Monitors