ACS37220LEZATR-150B3 Current Sensor Compact Carrier -150A to +150A, 3.3V

Pololu are offering these breakout boards with support from Allegro Microsystems as an easy way to use or evaluate their ACS37220 Hall effect-based, electrically isolated current sensors with user-configurable overcurrent fault output; Pololu therefore recommend careful reading of the ACS37220 datasheet before using this product. The following list details some of the sensor’s key features:

• Hall effect-based sensor with electrically isolated current path allows the sensor to be inserted anywhere along the current path and to be used in applications that require electrical isolation.
• Extra-low primary current path resistance of 0.1 mO in the sensor IC for higher efficiency.
• Differential Hall sensing rejects common-mode fields, so the orientation of the sensor relative to uniform external magnetic fields (e.g. the Earth’s magnetic field) has less effect on the measurement.
• High-bandwidth 150 kHz analog output voltage proportional to AC or DC currents.
• Less than 4 µs response time.
• Output is not ratiometric (i.e. the zero point and sensitivity are independent of the actual supply voltage), which provides immunity from noisy supplies.
• User-configurable overcurrent fault output with 3 µs response time indicates when the current magnitude exceeds the set threshold and can be used for fast short-circuit detection.
• Integrated digital temperature compensation circuitry allows improved accuracy over the full operating temperature range.
• Automotive-grade operating temperature range of -40°C to 150°C.
• Carrier boards, available in compact and large sizes, offer a variety of ways to insert it into the current path along with 0.1"-pitch (breadboard-compatible) power, ground, and output pins.
• The PCB is made with 2-layer (compact versions) or 6-layer (large versions) 2-oz copper, so very little power is lost in the module.
• 3.3V and 5V versions available.

The connection points are labeled on the silkscreen, which is on the bottom side of the compact versions and on both sides of the large versions. The bottom silkscreen also shows the direction that is interpreted as positive current flow via the +i arrow.

Details for item #5291

This compact carrier features the ACS37220LEZATR-150B3, which is intended for nominal 3.3 V operation and is designed for bidirectional input current from -150 A to +150 A. This version can be visually distinguished from the other versions by the “3V3 B15” printed on the bottom side.

The FAULT, VOUT, VDD, GND, and VOC pins work with 0.1"-pitch header pins and are compatible with standard solderless breadboards.

Warning: This product is intended for use below 30 V. Working with higher voltages can be extremely dangerous and should only be attempted by qualified individuals with appropriate equipment and experience.

Schematic and dimension diagrams

The dimension diagram is available as a downloadable PDF (403k pdf).

Real-world power dissipation considerations

Depending on the version, the ACS37220 can measure up to ±200 A. However, the sensor chip can overheat at lower currents. In Pololu's tests, Pololu found that Pololu's ACS37220 carrier boards could conduct 60 A continuously while staying well below the thermal limit for the IC. Pololu's tests were conducted at approximately 25°C ambient temperature with no forced air flow.

The actual current you can pass through the sensor will depend on how well you can keep it cool. The carrier’s printed circuit board is designed to help with this by drawing heat out of the sensor chip. Solid connections to the current path pins (such as with thick soldered wires or large, tightly-secured lugs) can also help reduce heat build-up in the sensor and carrier board.

Warning: Exceeding temperature or current limits can cause permanent damage to the sensor. If you are measuring an average continuous current greater than 50 A, Pololu strongly recommend that you monitor the sensor’s temperature and look into additional cooling if necessary.

This product can get hot enough to burn you long before the chip overheats. Take care when handling this product and other components connected to it.

Comparison of the Pololu current sensor carriers

Pololu have a variety of current sensors available with different ranges, sensitivities, and features. The table below summarizes Pololu's selection of active and preferred options:

Dimensions

General specifications

Identifying markings

Notes:

1

Typical.

File downloads

• Dimension diagrams of the ACS37220 Current Sensor Carriers (403k pdf)

• 3D model of the ACS37220 Current Sensor Compact Carriers (4MB step)

• Drill guide for the ACS37220 Current Sensor Compact Carriers (19k dxf)

  This DXF drawing shows the locations of all of the board’s holes.

Recommended links

• ACS37220 datasheet

• Allegro product page for the ACS37220 Hall-based Current Sensor

  Allegro product page for the ACS37220, where you can find additional application notes and other resources.