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ACS724LLCTR-20AU Current Sensor Carrier 0A to 20A

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Pololu item #: 4044
Brand: Pololu
Status: Active and Preferred 

This board is a simple compact carrier of Allegro’s ACS724LLCTR-20AU Hall effect-based, electrically isolated current sensor, which offers a low-resistance (~1.2 mΩ) current path and a high 120 kHz bandwidth for fast response times.

Alternatives available with variations in these parameter(s): current range Select variant…

Compare all products in ACS724 Current Sensor Carriers.

Pictures

ACS724LLCTR-20AU Current Sensor Carrier 0A to 20A.

ACS724 current sensor carrier, bottom view with dimensions.

ACS724 Current Sensor Carrier pinout.

Schematic diagram of the ACS724 Current Sensor Carrier.

ACS724LLCTR-20AU Current Sensor Carrier 0A to 20A with included 0.1″ header pins.

ACS724LLCTR-20AU Current Sensor Carrier 0A to 20A, top view.

Current sensor carrier soldered with high-current wires.

Current sensor carrier with solderless ring terminal connectors (not included).

Standard packaging for the ACS724LLCTR-20AU Current Sensor Carrier 0A to 20A.

Overview

We are offering these breakout boards with support from Allegro Microsystems as an easy way to use or evaluate their ACS724LLCTR Hall effect-based, electrically isolated current sensors; we therefore recommend careful reading of the ACS724 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.
• 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.
• The conductive path internal resistance is typically 1.2 mΩ, and the PCB is made with 2-oz or 4-oz copper, depending on the sensor version, so very little power is lost in the module.
• High-bandwidth 120 kHz analog output voltage proportional to AC or DC currents.
• Typical 4 µs response time.
• Optional FILTER pin simplifies bandwidth limiting for better noise reduction and improved resolution at lower frequencies.
• Integrated digital temperature compensation circuitry allows for near closed loop accuracy over temperature in an open loop sensor.
• Automotive-grade operating temperature range of -40°C to 150°C.
• 0.7″×0.8″ carrier board offers a variety of ways to insert it into the current path along with 0.1″-pitch (breadboard-compatible) power, ground, and output pins.
• Unidirectional and bidirectional versions available.

The pads are labeled on the bottom silkscreen, as shown in the picture to the right. The silkscreen also shows the direction that is interpreted as positive current flow via the +i arrow.

A variety of options are available with different current sensing ranges and sensitivities:

Alternatives available with variations in these parameter(s): current range Select variant…

These versions all look very similar, and while you can distinguish them by reading the text on the IC, we also provide a white box on the bottom silkscreen where you can add your own distinguishing markings if so desired.

Details for item #4044

ACS724LLCTR-20AU Current Sensor Carrier 0A to 20A, top view.

ACS724LLCTR-20AU Current Sensor Carrier 0A to 20A with included 0.1″ header pins.

This carrier features the ACS724LLCTR-20AU, which operates at 5 V and is designed for unidirectional input current from 0 A to 20 A. This version can be visually distinguished from the other versions by the “20AU” written on the IC as shown in the pictures above.

When Vcc is 5 V, the output voltage has a zero point at 0.5 V and increases by 200 mV per amp of input current. More generally, More generally, the sensor’s zero point and sensitivity depend on VCC as follows:

``text(Zero Point) = V_"CC" / 10``

``text(Sensitivity) = 0.2 text(V)/text(A) * (1 + ((V_"CC" – 5 text(V)) * 1.3) / (5 text(V)))``

This board ships assembled with all surface mount components, and a 3×1 strip of 0.1″ header pins is included but not soldered in.

Using the sensor

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

The sensor requires a supply voltage of 4.5 V to 5.5 V to be connected across the VCC and GND pads, which are labeled on the bottom silkscreen, and the sensor outputs an analog voltage with a linear relationship to the input current:

``V_"IOUT" = text(Zero Point) + text(Sensitivity) * I_"P"``

``I_"P" = (V_"IOUT" – text(Zero Point)) / text(Sensitivity)``

The FILTER pin lets you adjust the board’s bandwidth by adding a capacitor to ground (a ground pad has been added next to the FILTER pin for convenience) in parallel with the 1 nF capacitor that is already on the board. Without an added external filter capacitor, the bandwidth is about 90 kHz. The datasheet provides more information on how the filter capacitors affect bandwidth.

You can insert the board into your current path in a variety of ways. For low-current applications, you can solder 0.1″ male header pins to the board via the smallest pair of through-holes on the input-current side of the board. For higher-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 8 AWG wires or #6 or M3.5 screws, and the second-largest through-holes (and mounting holes) are sized for 12 AWG wires or #2 or M2 screws.

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

Schematic diagram of the ACS724 Current Sensor Carrier.

The dimension diagram is available as a downloadable PDF (1MB pdf).

Comparison of the Pololu current sensor carriers

We have a variety of current sensors available with different ranges, sensitivities, and features. The table below summarizes our 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 ±200 A / 6.6 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 ±200 A / 6.6 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 ±70 A / 14.3 mV/A 3.3V Unidirectional: 0–⁠20 A / 100 mv/A 0–⁠30 A / 66.7 mv/A 0–⁠50 A / 40 mv/A 0–⁠65 A / 30.8 mv/A 5V Bidirectional: ±20 A / 100 mV/A ±30 A / 66.7 mV/A ±50 A / 40 mV/A ±65 A / 30.8 mV/A 5V Unidirectional: 0–⁠20 A / 200 mv/A 0–⁠30 A / 133.3 mv/A 0–⁠50 A / 80 mv/A 0–⁠70 A / 57.1 mv/A	3.3V Bidirectional: ±50 A / 20 mV/A ±70 A / 14.3 mV/A 3.3V Unidirectional: 0–⁠50 A / 40 mv/A 0–⁠65 A / 30.8 mv/A 5V Bidirectional: ±50 A / 40 mV/A ±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 mΩ	0.6 mΩ	0.6 mΩ	0.1 mΩ		0.2 mΩ		1 mΩ
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-piece price	$3.49	$3.95	$6.95 – $7.49	$4.95	$7.95	$9.95	$12.95	$8.95	$12.95

⁽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.

You can also use the following selection box to see all these options sorted by current range:

Alternatives available with variations in these parameter(s): current range Select variant…

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