Precision bi-directional current sense covers -5V to 110V

Author: EIS Release Date: Nov 24, 2022

Texas instruments has introduced a precision bi-directional current sense amplifier than can measure voltage drops across shunt resistors over a common-mode range of -5 to 110V, with survival across -20 to +120V.

 

TI INA296A precision current sense amplifier

Bias current is 35µA within the operating range, and that operating range is independent of the 2.7 to 20V single rail supply voltage, from which 2.5mA is drawn. Operation is also over -40 to +125°C.

 

“The high precision current measurement is achieved through a combination of ±10µV maximum offset voltage, ±0.01% gain error and typically 166dB dc common-mode rejection ratio.

 

Operation is fast, with a bandwidth of 1.1MHz, 8V/µs slew rate and 1µs step settling time to 1%, allowing transient detection and fast over-current protection.

 

There are 5 options:

 

INA296A1 – 10V/V

INA296A2 – 20V/V

INA296A3 – 50V/V

INA296A4 – 100V/V

INA296A5 – 200V/V

With are specified with ±10µV max offset (±0.1µV/°C drift) and ±0.01% max gain error (±1ppm/°C drift).

 

For less challenging applications, replace ‘A’ in the part number with ‘B’ to get ±150µV max offset (±0.5µV/°C drift) and ±0.1% max gain error (±5ppm/°C drift).

 

By re-arranging connections to the two internal reference resistors, unidirectional output referenced to 0V or Vcc, or bi-directional output referenced to Vcc/2 or half an external voltage reference is available. Adding external components allow more arrangements – see the data sheet.

 

48V applications are foreseen in dc-dc converters, battery management, servers and merchant networks, as well as generally in test, measurement and macro remote radios.

 

TI INA296AEVM current sense evaluation boardFor evaluation, a board is available (see photo) with five partially-populated current sensor circuit layouts: 10, 20 and 50V/V ICs are in-position, while space is provided for 100 and 200V/V ICs. None of the sense resistors are installed (or provided), and there are spaces for filtering capacitors.