ACS37041KLHBLT-010B3 Current Sensor Compact Carrier -10A to +10A, 3.3V

Pololu are offering these breakout boards with support from Allegro Microsystems as an easy way to use or evaluate their ACS37041 and ACS37042 Hall effect-based, electrically isolated current sensors; Pololu therefore recommend careful reading of the ACS37041/2 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 galvanic isolation.
• Low primary current path resistance of 1.6 mO in the sensor IC, so very little power is lost in the module.
• 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 5 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.
• Integrated temperature compensation circuitry allows improved accuracy over the full operating temperature range.
• Automotive-grade operating temperature range of -40°C to 125°C.
• Carrier boards, available in micro (0.3×0.4) and Pololu's standard compact (0.7×0.8) 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.
• 3.3V and 5V versions available.
• ACS37042 ICs have a higher isolation rating and are on PCBs with routed slots for higher creepage.

The connection points and the direction interpreted as positive current flow are labeled on the bottom silkscreen.

Details for item #5444

This compact carrier features the ACS37041KLHBLT-010B3, which is intended for nominal 3.3 V operation and is designed for bidirectional input current from -10 A to +10 A. This version can be visually distinguished from the other versions by the “3V3 B10” printed on the bottom side.

A smaller micro carrier is also available for this sensor IC for more space-constrained applications or to evaluate the IC’s performance with a small PCB area for thermal dissipation.

Using the sensor

This sensor has five required connections: the input current (IP+ and IP-), logic power (VDD and GND), and the sensor output (VOUT).

The sensor requires a supply voltage of 3.0 V to 3.6 V to be connected across the VDD and GND pads, which are labeled on the bottom silkscreen. The sensor outputs an analog voltage on VOUT that is centered at 1.65 V and changes by 132 mV per amp of input current, with positive current increasing the output voltage and negative current decreasing the output voltage:

VOUT=1.65V+0.132VA·IPVOUT=1.65V+0.132VA·IP

IP=VOUT–1.65V0.132VA=(VOUT–1.65V)·7.58AVIP=VOUT–1.65V0.132VA=(VOUT–1.65V)·7.58AV

The output is not ratiometric, so the zero point and sensitivity are independent of the actual supply voltage.

Making connections to the board

You can insert the board into your current path in a variety of ways. For typical high-current applications, you can solder wires directly to the through-holes that best match your wires, or you can use solderless ring terminal connectors. The largest through-holes are big enough for 10 AWG wires or #6 or M3.5 screws, and the second-largest through-holes (and mounting holes) are sized for 14 AWG wires or #2 or M2 screws. Holes with 0.1, 3.5 mm, and 5 mm spacing are also available as shown in the diagram above for connecting male header pins or terminal blocks, but please note that these connection options will generally not be suitable for the kinds of high currents intended for this sensor.

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

Isolation rating and board creepage considerations

The ACS37041 and ACS37042 differ in their manufacturer-rated isolation voltages of 100 V_RMS and 285 V_RMS, respectively. The carrier PCBs for the ACS37042 ICs have routed slots under the IC bodies to increase the creepage distance between the isolated sections from 1.6 mm to 3.0 mm. A rough rule of thumb is that uncontaminated FR4 PCBs should have roughly 1 mm of creepage per 100 V_RMS of isolation. Please note that these carrier boards are not certified to any particular safety standard.

Warning: This product is generally intended for use below 30 V, and many of the application example pictures (e.g. use on a breadboard) are appropriate for such lower-voltage applications. These boards can be used at higher voltages, but 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 (416k pdf).

Real-world power dissipation considerations

In Pololu's tests, Pololu found that the micro carrier boards (cs08a and cs08c) could conduct about 25 A continuously, and compact carrier boards (cs08b and cs08d) could conduct about 30 A continuously, without reaching 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 20 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.

Dimensions

General specifications

Identifying markings

Notes:

1

Typical.

File downloads

• Dimension diagram of the ACS3704x Current Sensor Carriers (683k pdf)

• 3D model of the ACS37041 Current Sensor Compact Carriers (3MB step)

• Drill guide for the ACS37041 Current Sensor Compact Carriers (18k dxf)

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

• 3D model of the ACS37042 Current Sensor Compact Carriers (3MB step)

• Drill guide for the ACS37042 Current Sensor Compact Carriers (18k dxf)

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

Recommended links

• ACS37041/2 datasheet

• Allegro product page for the ACS37041 and ACS37042 Integrated Hall-Effect Current Sensors

  Allegro product page for the ACS37041/2, where you can find application notes and other resources.