CT433-HSWF50MR TMR Current Sensor Compact Carrier -50A to +50A, 3.3V

The CT432/CT433 TMR Current Sensor Compact Carrier features the CT433-HSWF50MR, which is intended for nominal 3.3 V operation and is designed for bidirectional input current from -50 A to +50 A. This version can be visually distinguished from the other versions by the part number printed on the sensor IC, as shown in the left picture above (the bottom silkscreen also has a blank white box that can be used for adding customized identifying markings).

This sensor has five required connections: the input current (IP+ and IP-), logic power (VCC 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 VCC 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 20 mV per amp of input current, with positive current increasing the output voltage and negative current decreasing the output voltage:

V_OUT = 1.65 V + 0.02 V/A · I_P

I_P = (V_OUT – 1.65 V) / 0.02 V/A = (V_OUT – 1.65 V) · 50 A/V

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

The optional FLT pin is normally at VCC and is pulled low when the IP current magnitude exceeds 110% of the maximum sensing range. This pin only asserts while the fault condition is present (it is not latched).

Note: The datasheet warns that using the FLT (TEST) pin as a fault output rather than grounding it will reduce the sensor’s immunity to high dV/dt events. If you do not need the fault feature, you can externally connect this pin to ground. Alternatively, Pololu has the ability to custom-assemble these boards with this pin grounded (which would also disable the fault feature). If you are interested in customization, please contact us.

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 for connecting male header pins or terminal blocks, but please note that these connection options are generally not suitable for high currents and could limit the usable range of the sensor.

The FLT, VOUT, VCC, and GND 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.

The dimension diagram is available as a downloadable PDF (436k pdf).

Real-world power dissipation considerations

Depending on the version, the CT432 and CT433 can measure up to ±70 A. However, the sensor chip will typically overheat at lower currents. In Pololu's tests, Pololu found that the 2-layer CT432/CT433 compact carrier board could conduct about 45 A continuously, and the 4-layer compact carrier board could conduct about 50 A continuously, without reaching the thermal limit for the IC. (Sensors with ranges under 45 A use the cs07a board while sensors with ranges over 45 A use the cs07b board.) 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 30 A, Pololu strongly recommends 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 has a variety of current sensors available with different ranges, sensitivities, and features. The table below summarizes Pololu's selection of active and preferred options:

General specifications

Identifying markings

Notes:

1

Typical.

File downloads

• Dimension diagrams of the CT432/CT433 Current Sensor Carriers (436k pdf)

• 3D model of the CT432/CT433 Current Sensor Compact Carriers (4MB step)

• Drill guide for the CT432/CT433 Current Sensor Compact Carriers (20k dxf)

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

Recommended links

• CT432 datasheet

• CT433 datasheet

• Allegro product page for the CT432 TMR Current Sensor

  Allegro product page for the CT432, where you can find additional application notes and other resources.

• Allegro product page for the CT433 TMR Current Sensor

  Allegro product page for the CT433, where you can find additional application notes and other resources.