This board is a simple carrier of Allegro’s bidirectional ±2.5A ACS724LLCTR- 2P5AB Hall effect-based linear current sensor, which offers a low-resistance (~1.2 mΩ) current path and electrical isolation up to 2.4 kV RMS.
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This current sensor is a carrier board or breakout board for Allegro’s ACS724LLCTR Hall effect-based linear current sensors; we therefore recommend careful reading of the ACS724 datasheet (2MB pdf) before using this product. The following list details some of the sensor’s key features:
The pads are labelled 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:
ACS724 Current Sensor Carriers | ||
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Sensitivity(1) | Unidirectional range | Bidirectional range |
800 mV/A | 0A to 5A | -2.5A to +2.5A |
400 mV/A | 0A to 10A | -5A to +5A |
200 mV/A | 0A to 20A | -10A to +10A |
133 mV/A | 0A to 30A | |
100 mV/A | -20A to +20A | |
66 mV/A | -30A to +30A | |
40 mV/A | -50A to +50A | |
1 Sensitivity shown for Vcc = 5V. |
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.
This carrier features the ACS724LLCTR-2P5AB, which operates at 5 V and is designed for bidirectional input current from -2.5 A to +2.5 A. When Vcc is 5 V, the output voltage is centred at 2.5 V and changes by 800 mV per amp of input current, with positive current increasing the output voltage and negative current decreasing the output voltage.
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.
This sensor has five required connections: the input current (IP+ and IP-), logic power (VCC and GND), and the sensor output (OUT).
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 labelled on the bottom silkscreen, and the sensor outputs an analogue voltage that is linearly proportional to the input current.
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 pair of through-holes are big enough for #6 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 protective gear.
The dimension diagram is available as a downloadable PDF (1MB pdf).
We have a variety of current sensors available with different ranges, sensitivities, and features. You can use the following table to compare our options:
ACS711EX Current Sensor Carriers |
ACHS-712x CurrentSensor Carriers |
ACS724 CurrentSensor Carriers |
ACS709 Current Sensor Carrier |
|
---|---|---|---|---|
Sensor IC: | Allegro ACS711KEXLT |
Broadcom ACHS-712x |
Allegro ACS724LLCTR |
Allegro ACS709LLFTR-35BB |
Current range / sensitivity(1): |
Bidirectional: ±15.5 A / 136 mV/A ±31 A / 68 mV/A |
Bidirectional: ±10 A / 185 mV/A ±20 A / 100 mV/A ±30 A / 66 mV/A ±40 A / 50 mV/A ±50 A / 40 mV/A |
Unidirectional: 0–5 A / 800 mv/A 0–10 A / 400 mv/A 0–20 A / 200 mv/A 0–30 A / 133 mV/A Bidirectional: ±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 |
Bidirectional: ±75 A / 28 mV/A |
Path resistance: | 0.6 mΩ | 0.7 mΩ | 1.2 mΩ | 1.1 mΩ |
Max bandwidth: | 100 kHz | 80 kHz(2) | 120 kHz(2) | 120 kHz(2) |
Vcc range:(1) | 3 V–5.5 V | 4.5 V–5.5 V | 4.5 V–5.5 V | 3 V–5.5 V |
Size: | 0.7″ × 0.8″ | 0.7″ × 0.8″ | 0.7″ × 0.8″ | 0.82″ × 0.9″ |
Special features: | over-current fault pin | differential Hall sensing rejects common-mode fields for higher accuracy, integrated digital temperature compensation |
configurable over-current threshold |
|
1-piece price: | $3.95 | $6.95 | $11.95 | $14.95 |
(1) Sensitivity shown for Vcc = 5V. | ||||
(2) Bandwidth can be reduced by adding a filter capacitor. |
Size: | 0.7" x 0.8" |
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Weight: | 1.1 g |
Current sense: | 0.800 V/A1 |
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Minimum logic voltage: | 4.5 V |
Maximum logic voltage: | 5.5 V |
Supply current: | 14 mA2 |
Version: | -2.5A to +2.5A (bidirectional 2.5A) |
Current sensor: | Allegro ACS724LLCTR-2P5AB |
PCB dev codes: | cs01a |
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Other PCB markings: | 0J1214, blank white box |
This DXF drawing shows the locations of all of the board’s holes. The through-hole sizes and locations in this file also apply to cs01b versions of the PCB, though some of the via locations are different.
This is the application note referenced on page 16 of the ACS724 datasheet. The ACS720 is used validate the test methods presented, but these same methods and principles would also apply to the ACS724.