Pololu Corporation 4045

This carrier board is a compact carrier for the Allegro ACS724LLCTR-20AB Hall effect current sensor. The sensor provides a low-resistance (~1.2 mΩ) current path and a high bandwidth of 120 kHz for fast response times. Based on the Hall effect, its current path features electrical isolation, allowing it to be inserted anywhere in the current path — suitable for applications requiring galvanic isolation. Differential Hall sensing suppresses common-mode magnetic fields, so the sensor's orientation relative to uniform external magnetic fields (such as the Earth's magnetic field) has minimal impact on measurements. The typical resistance of the internal conductive path is 1.2 mΩ, and the PCB uses 2 oz or 4 oz copper (depending on the sensor version), resulting in extremely low power dissipation in the module. The high-bandwidth 120 kHz analog output voltage is proportional to the input current, with a typical response time of 4 μs. An optional FILTER pin simplifies bandwidth limiting for improved noise performance at lower frequencies. An integrated digital temperature compensation circuit enables temperature compensation in the open-loop sensor. Operating temperature range is -40°C to 150°C. The 0.7" × 0.8" carrier board offers multiple ways to integrate it into a circuit, including breadboard-compatible power, ground, and output pins. Both unidirectional and bidirectional versions are available. This carrier board is equipped with the ACS724LLCTR-20AB sensor, operates at 5V, and is designed to measure bidirectional input currents from -20 A to +20 A. With Vcc at 5V, the output voltage is centered at 2.5V and changes by 100 mV per ampere of input current — positive current increases the output voltage while negative current decreases it. The sensor requires a supply voltage of 4.5V to 5.5V connected to the VCC and GND pads, and outputs an analog voltage linearly proportional to the input current. The FILTER pin allows bandwidth adjustment by adding a capacitor to ground (a ground pad is conveniently located near the FILTER pin), in parallel with the existing 1 nF capacitor on the board. Without an external filter capacitor, the bandwidth is approximately 90 kHz. The board can be inserted into the current path in multiple ways. For low-current applications, 0.1" male header pins can be soldered to the board using the smallest through-holes on the input current side. For high-current applications, wires can be soldered directly to the through-hole that best matches the wire size, or solder-free ring terminal connectors can be used. The largest through-holes accept 8 AWG wire or #6 or M3.5 screws; the second-largest through-holes (also mounting holes) accommodate 12 AWG wire or #2 or M2 screws.

• Hall effect-based sensor with electrically isolated current path, allowing insertion at any point in the current path; suitable for applications requiring electrical isolation.
• Differential Hall sensing suppresses common-mode magnetic fields, minimizing the influence of uniform external magnetic fields (e.g., Earth's magnetic field) on measurements regardless of sensor orientation.
• Typical internal conductor resistance of 1.2 mΩ with 2 oz or 4 oz PCB copper weight (depending on sensor version), resulting in extremely low module power dissipation.
• High-bandwidth 120 kHz analog output voltage proportional to input current, with typical response time of 4 μs.
• Optional FILTER pin simplifies bandwidth limiting for improved noise performance at lower frequencies.
• Integrated digital temperature compensation circuit enables temperature compensation in open-loop sensors.
• Operating temperature range: -40°C to 150°C.
• 0.7" × 0.8" carrier board offers multiple circuit integration options, including breadboard-compatible power, ground, and output pins.
• Available in unidirectional and bidirectional versions.