This is the large version of a simple carrier for Allegro’s ACS37220LEZATR-150B5 Hall effect-based, electrically isolated current sensor, which offers an extra-low-resistance (~0.1 mΩ) current path, a high 150 kHz bandwidth for fast response times, and an overcurrent fault output with a user-con...
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We are offering these breakout boards with support from Allegro Microsystems as an easy way to use or evaluate their ACS37220 Hall effect-based, electrically isolated current sensors with user-configurable overcurrent fault output; we therefore recommend careful reading of the ACS37220 datasheet before using this product. The following list details some of the sensor’s key features:
The connection points are labelled on the silkscreen, which is on the bottom side of the compact versions and on both sides of the large versions. The bottom silkscreen also shows the direction that is interpreted as positive current flow via the +i arrow.
The following table lists the available ACS37220 carrier options:
Pololu Item # |
Part Suffix | Supply Voltage (V) |
Current Range |
Sensitivity (mV/A) |
Zero Point | Size | PCB Details |
Price | |
---|---|---|---|---|---|---|---|---|---|
Large Carrier |
#5295 | 100B3 | 3.15 to 3.45 (3.3 nominal) |
±100 A | 13.2 | 1.65 V | 1.4″×1.2″ | 6 layers, 2-oz copper |
$7.95 |
#5296 | 150B3 | ±150 A | 8.8 | ||||||
#5297 | 100B5 | 4.5 to 5.5 (5 nominal) |
±100 A | 20 | 2.5 V | ||||
#5298 | 150B5 | ±150 A | 13.3 | ||||||
#5299 | 200B5 | ±200 A | 10 | ||||||
Compact Carrier |
#5290 | 100B3 | 3.15 to 3.45 (3.3 nominal) |
±100 A | 13.2 | 1.65 V | 0.7″×0.8″ | 2 layers, 2-oz copper |
$4.95 |
#5291 | 150B3 | ±150 A | 8.8 | ||||||
#5292 | 100B5 | 4.5 to 5.5 (5 nominal) |
±100 A | 20 | 2.5 V | ||||
#5293 | 150B5 | ±150 A | 13.3 | ||||||
#5294 | 200B5 | ±200 A | 10 |
This large carrier features the ACS37220LEZATR-150B5, which is intended for nominal 5 V operation and is designed for bidirectional input current from -150 A to +150 A. This version can be visually distinguished from the other versions by the “5V B15” printed on the bottom side, as shown in the left picture above.
Part Suffix | Range | Supply Voltage | Sensitivity | Zero Point | Size | PCB layers |
---|---|---|---|---|---|---|
150B5 | ±150 A (bidirectional) | 4.5 V to 5.5 V | 13.3 mV/A | 2.5 V | 1.4″×1.2″ | 6 |
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.
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 4.5 V to 5.5 V to be connected across the VDD and GND pads, which are labelled on the bottom silkscreen. The sensor outputs an analogue voltage on VOUT that is centred at 2.5 V and changes by 13.3 mV per amp of input current, with positive current increasing the output voltage and negative current decreasing the output voltage:
``V_"OUT" = 2.5 text(V) + 0.0133 text(V)/text(A) * I_"P"``
``I_"P" = (V_"OUT" – 2.5 text(V)) / (0.0133 text(V)/text(A)) = (V_"OUT" – 2.5 text(V)) * 75 text(A)/text(V)``
The output is not ratiometric, so the zero point and sensitivity are independent of the actual supply voltage.
The optional VOC pin can be used to set the overcurrent fault threshold. An on-board 205 kΩ resistor between VOC and GND sets the default overcurrent fault threshold to approximately 200% of the nominal sensing range, and an external resistor can be added in parallel between VOC and GND to lower this threshold to between 50% and 200%. The following equation gives the value of this parallel resistor, ROC, in kΩ as a function of overcurrent fault threshold percentage P:
``R_"OC" = (205 text(kΩ) * P) / (205% – P)``
So for example, to set the overcurrent fault limit to 50% of the nominal sensing range, a 66 kΩ external resistor can be added between VOC and GND:
``R_"OC" = (205 text(kΩ) * 50%) / (205% – 50%) ~~ 66 text(kΩ)``
As a shortcut, VOC can be connected directly to ground to set the overcurrent fault limit to 100% of the nominal sensing range.
Alternatively, the on-board resistor can be replaced, or a low-impedance voltage source can be applied directly to the VOC pin as described in the ACS37220 datasheet.
The optional FAULT pin is normally at VDD and is pulled low when the IP current magnitude exceeds the set overcurrent fault threshold in either direction. This pin only asserts while the fault condition is present (it is not latched).
We manufacture these boards in-house at our Las Vegas facility, which gives us the flexibility to make these current sensors with custom default overcurrent fault thresholds. If you are interested in customisation, please contact us.
You can insert the board into your current path in a variety of ways. The largest through-holes are 6.4 mm in diameter with 22 mm spacing. These can be used with #12 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 for connecting male header pins or terminal blocks, but please note that these smaller connection options are generally not suitable for high currents like those this sensor is intended for.
The FAULT, VOUT, VDD, GND, and VOC 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 (403k pdf).
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 CurrentSensor Carriers | ACS71240 CurrentSensor Carriers | ACS724 CurrentSensor Carriers | ACS37220Current SensorCompact Carriers | ACS37220Current SensorLarge Carriers | ACS72981Current SensorCompact Carriers | ACS72981Current SensorLarge Carriers | |
Sensor IC | Allegro ACS711KEXT |
Allegro ACS71240 |
Allegro ACS724LLCTR |
Allegro ACS37220 | Allegro ACS72981xLR | ||
---|---|---|---|---|---|---|---|
Vcc 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 |
||
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 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 5V Bidirectional:(2) ±50 A / 40 mV/A ±100 A / 20 mV/A 5V Unidirectional:(2) 0–100 A / 40 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 5V Bidirectional:(2) ±50 A / 40 mV/A ±100 A / 20 mV/A 5V Unidirectional:(2) 0–100 A / 40 mv/A |
IC path resistance | 0.6 mΩ | 0.6 mΩ | 0.6 mΩ | 0.1 mΩ | 0.2 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 |
Max bandwidth | 100 kHz | 120 kHz | 120 kHz(3) | 150 kHz | 250 kHz | ||
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″ |
Overcurrent fault output | User-configurable threshold | ||||||
Differential sensing | |||||||
Non-ratiometric output | |||||||
1-piece price | $3.49 | $3.95 | $6.95 – $7.49 | $4.95 | $7.95 | $9.95 | $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. |
Size: | 1.4″ × 1.2″ |
---|---|
Weight: | 4.1 g |
Typical operating voltage: | 5 V |
---|---|
Current sense: | 13.3 mV/A |
Minimum logic voltage: | 4.5 V |
Maximum logic voltage: | 5.5 V |
Supply current: | 16 mA1 |
Version: | -150A to +150A (bidirectional 150A), 5V |
Current sensor: | Allegro ACS37220LEZATR-150B5 |
PCB dev codes: | cs06b |
---|---|
Other PCB markings: | 0J14835 |
Other PCB markings: | 5V B15 |
This DXF drawing shows the locations of all of the board’s holes.
Allegro product page for the ACS37220, where you can find additional application notes and other resources.