Components

Isolated AEC-Q100 Hall Effect Current Sensor ICs

Allegro MicroSystems announced a new family of automotive AEC-Q100 qualified, monolithic Hall effect current sensor ICs. Small and energy efficient, the ACS71240 family is suitable for electric vehicle chargers, dc-dc converters, and industrial motors, as well as IOT applications. These new devices offer improvements compared to the Allegro ACS711 predecessor.

First, unlike the previous model, the family features output signal immunity to stray magnetic fields (produced by adjacent motors or current carrying wires). Secondly, the family provides enhanced output signal accuracy (less than +/-1.5% typical).

Also, the company says that the family’s output signal is immune to noisy supply voltage rails.

Finally, a dedicated over-current fault output with a typical response time of 1.5µs improves system safety. This fault output offers a simple means of detecting short circuit events that can prevent damage to MOSFETs or IGBTs in inverter, motor, and other switching power electronics applications.

“Allegro was the first company to introduce the Hall-based, flip-chip integrated current sensors that make it possible to have simple surface mount assembly, great SNR and low power losses while using a small PCB area,” explains Shaun Milano, Director of Allegro’s Current Sensor Product Line. “This new family represents the evolution of these innovative products and offers our customers improved safety, reliability, and efficiency.”

The device comes in two small form factor package options, each having different levels of galvanic isolation. The 3mm x 3mm, wettable flank QFN package can be used on voltage rails up to 120Vdc and enables solder joint inspection required in zero PPM automotive applications.

The standard footprint SOIC8 package is UL certified to 2400VRMS of isolation and offers a working voltage of 420Vdc or 297VRMS.

Allegro designed the ACS71240 family to replace shunt resistors, operational amplifiers, voltage isolators, and current transformers in applications that require small form factor, monolithic sensors. According to Allegro, these fully integrated solutions reduce the overall cost of current sensing by eliminating discrete components that demand printed circuit board area.

The sensors are offered for use with 5V or 3.3V power supplies.

Features
  • AEC-Q100 qualified
  • Differential Hall sensing rejects common-mode stray magnetic fields
  • Over-current FAULT with a Factory Programmable trip range of 50% to 200% of full-scale current
  • Non-Ratiometric output provides immunity to noisy supplies
  • Galvanically Isolated:
    • QFN package: 120Vdc working voltage
    • SOIC8 package: UL certified to 2400VRMS, working voltage of 420Vdc or 297VRMS
  • Reduced Power Loss:
    • 0.6mΩ internal conductor resistance on QFN package
    • 1.2mΩ internal conductor resistance on SOIC8 package
  • Integrated shield virtually eliminates capacitive coupling from current conductor to die, greatly suppressing output noise due to high dv/dt transients
  • Output voltage proportional to ac or dc current
  • High-bandwidth 120kHz analog output for faster response times in control applications
  • Factory-trimmed sensitivity and quiescent output voltage for improved accuracy
  • 3.3V and 5V single supply operation
  • Small footprint, low-profile QFN and SOIC8 packages suitable for space-constrained applications
Allegro MicroSystems, Inc.
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