CT432-HSWF70DR TMR Current Sensor Large Carrier 0A to 70A, 5V

This large carrier features the CT432-HSWF70DR, which is intended for nominal 5 V operation and is designed for unidirectional input current from 0 A to 70 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).

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

Using the sensor

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 4.75 V to 5.5 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 has a zero point at 0.5 V and increases by 57.1 mV per amp of input current:

VOUT=0.5V+0.0571VA⋅IP" role="presentation" style="position: relative;">VOUT=0.5V+0.0571VA·IP$V_{\text{OUT}}=0.5\text{V}+0.0571\frac{\text{V}}{\text{A}}·I_{\text{P}}$

IP=VOUT–0.5V0.0571VA=(VOUT–0.5V)⋅17.5AV" role="presentation" style="position: relative;">IP=VOUT–0.5V0.0571VA=(VOUT–0.5V)·17.5AV$I_{\text{P}}=\frac{V_{\text{OUT}}–0.5\text{V}}{0.0571\frac{\text{V}}{\text{A}}}=(V_{\text{OUT}}–0.5\text{V})·17.5\frac{\text{A}}{\text{V}}$

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 have 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.

Making connections to the board

You can insert the board into your current path in a variety of ways. The largest through-holes are 6.6 mm in diameter with 22 mm spacing. These can be used with 1/4" or M6 screws for attaching various types of lugs or solderless ring terminals, or thick wires up to 4 AWG can be soldered directly to the board. The slots near the edge of the board can accommodate a 4-pin terminal block or other connector with a pitch between 7.5 mm and 9.5 mm. 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 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.

Schematic and dimension diagrams

CT432/CT433 TMR Current Sensor Carrier schematic diagram.

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

Real-world power dissipation considerations

Thermal image of a high-current test of a Pololu current sensor carrier (not necessarily this product).

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 Pololu's 6-layer CT432/CT433 large carrier board could conduct about 55 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 30 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:

	ACS711 Current Sensor Carriers	ACS71240 Current Sensor Carriers	ACS724 Current Sensor Carriers	ACS37220 Current Sensor Compact Carriers	ACS37220 Current Sensor Large Carriers	ACS72981 Current Sensor Compact Carriers	ACS72981 Current Sensor Large Carriers	CT432/CT433 TMR Current Sensor Compact Carriers	CT432/CT433 TMR Current Sensor Large Carriers
Sensor IC	Allegro ACS711KEXT	Allegro ACS71240	Allegro ACS724LLCTR	Allegro ACS37220		Allegro ACS72981xLR		Allegro CT432/CT433
Sensing technology	Hall effect	Hall effect	Hall effect	Hall effect		Hall effect		XtremeSense™ TMR (tunneling magnetoresistance)
Logic voltage range (V)	3.0–5.5	3.3V versions: 3.0–3.6 5V versions: 4.5–5.5	4.5–5.5	3.3V versions: 3.15–3.45 5V versions: 4.5–5.5		3.3V versions: 3.0–3.6 5V versions: 4.5–5.5		3.3V versions: 3.0–3.6 5V versions: 4.75–5.5
Current range / sensitivity	Bidirectional:(1) ±15.5 A / 90 mV/A ±31 A / 45 mV/A	3.3V Bidirectional: ±10 A / 132 mV/A ±30 A / 44 mV/A ±50 A / 26.4 mV/A 5V Bidirectional: ±10 A / 200 mV/A ±30 A / 66 mV/A ±50 A / 40 mV/A 5V Unidirectional: 0–?50 A / 80 mv/A	5V Bidirectional:(2) ±2.5 A / 800 mV/A ±5 A / 400 mV/A ±10 A / 200 mV/A ±20 A / 100 mV/A ±30 A / 66 mV/A ±50 A / 40 mV/A 5V Unidirectional:(2) 0–?5 A / 800 mv/A 0–?10 A / 400 mv/A 0–?20 A / 200 mv/A 0–?30 A / 133 mV/A	3.3V Bidirectional: ±100 A / 13.2 mV/A ±150 A / 8.8 mV/A 5V Bidirectional: ±100 A / 20 mV/A ±150 A / 13.3 mV/A ±200 A / 10 mV/A	3.3V Bidirectional: ±100 A / 13.2 mV/A ±150 A / 8.8 mV/A 5V Bidirectional: ±100 A / 20 mV/A ±150 A / 13.3 mV/A ±200 A / 10 mV/A	3.3V Bidirectional:(1) ±50 A / 26.4 mV/A ±100 A / 13.2 mV/A ±150 A / 8.8 mV/A 3.3V Unidirectional:(1) 0–?50 A / 52.8 mv/A 0–?100 A / 26.4 mv/A 0–?150 A / 17.6 mv/A 0–?200 A / 13.2 mv/A 5V Bidirectional:(2) ±50 A / 40 mV/A ±100 A / 20 mV/A ±150 A / 13.3 mV/A ±200 A / 10 mV/A 5V Unidirectional:(2) 0–?100 A / 40 mv/A 0–?150 A / 26.7 mv/A	3.3V Bidirectional:(1) ±50 A / 26.4 mV/A ±100 A / 13.2 mV/A ±150 A / 8.8 mV/A 3.3V Unidirectional:(1) 0–?50 A / 52.8 mv/A 0–?100 A / 26.4 mv/A 0–?150 A / 17.6 mv/A 0–?200 A / 13.2 mv/A 5V Bidirectional:(2) ±50 A / 40 mV/A ±100 A / 20 mV/A ±150 A / 13.3 mV/A ±200 A / 10 mV/A 5V Unidirectional:(2) 0–?100 A / 40 mv/A 0–?150 A / 26.7 mv/A	3.3V Bidirectional: ±20 A / 50 mV/A ±30 A / 33.3 mV/A ±50 A / 20 mV/A 5V Bidirectional: ±20 A / 100 mV/A ±30 A / 66.7 mV/A ±65 A / 30.8 mV/A 5V Unidirectional: 0–?50 A / 80 mv/A 0–?70 A / 57.1 mv/A	3.3V Bidirectional: ±50 A / 20 mV/A 5V Bidirectional: ±65 A / 30.8 mV/A 5V Unidirectional: 0–?50 A / 80 mv/A 0–?70 A / 57.1 mv/A
IC path resistance	0.6 mO	0.6 mO	0.6 mO	0.1 mO		0.2 mO		1 mO
PCB	2 layers, 2-oz copper	2 layers, 2-oz copper	2 layers, 2- or 4-oz copper(4)	2 layers, 2-oz copper	6 layers, 2-oz copper	6 layers, 2-oz copper	6 layers, 2-oz copper	2 or 4 layers(5), 2-oz copper	6 layers, 2-oz copper
Max bandwidth	100 kHz	120 kHz	120 kHz(3)	150 kHz		250 kHz		1 MHz
Size	0.7" × 0.8"	0.7" × 0.8"	0.7" × 0.8"	0.7" × 0.8"	1.4" × 1.2"	0.7" × 0.8"	1.4" × 1.2"	0.8" × 1.1"	1.4" × 1.2"
Overcurrent fault output				User-configurable threshold
Common-mode field rejection
Non-ratiometric output

⁽¹⁾ Sensitivity when Vcc = 3.3 V; sensitivity is ratiometric.
⁽²⁾ Sensitivity when Vcc = 5 V; sensitivity is ratiometric.
⁽³⁾ Bandwidth can be reduced by adding a filter capacitor.
⁽⁴⁾ ±50A version uses 4-oz copper PCB; all other versions use 2-oz copper.
⁽⁵⁾ 50A and higher versions use 4-layer PCB; all other versions use 2-layer PCB.

Dimensions

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 Large Carriers (1MB step)

• Drill guide for the CT432/CT433 Current Sensor Large Carriers (19k 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.