ACS712 Current Sensor: Pinout, Datasheet and Circuit

The Allegro™ ACS712 provides economical and precise solutions for AC or DC current sensing in industrial, commercial, and communications systems. The device package allows for easy implementation by the customer. Typical applications include motor control, load detection and management, switchmode power supplies, and overcurrent fault protection. The device is not intended for automotive applications.

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Allegro MicroSystems ACS712ELCTR-20A-T technical specifications, attributes, parameters and parts with similar specifications to Allegro MicroSystems ACS712ELCTR-20A-T.

• Low-noise analog signal path

• Device bandwidth is set via the new FILTER pin

• 5 µs output rise time in response to step input current

• 80 kHz bandwidth ▪ Total output error 1.5% at TA= 25°C

• Small footprint, low-profile SOIC8 package

• 1.2 mΩ internal conductor resistance

• 2.1 kVRMS minimum isolation voltage from pins 1-4 to pins 5-8

• 5.0 V, single supply operation

• 66 to 185 mV/A output sensitivity

• Output voltage proportional to AC or DC currents

• Factory-trimmed for accuracy ▪ Extremely stable output offset voltage

• Nearly zero magnetic hysteresis

• Ratiometric output from supply voltage

ACS759, WCS1700, KG190, ACS715

• Motor speed control in motor control circuits.

• Electrical load detection and management.

• Switched-mode power supplies (SMPS)

• Protection for over-current.

These ACS712 module can measure current AC or DC current ranging from +5A to -5A, +20A to -20A and +30A to -30A. You have to select the right range for your project since you have to trade off accuracy for higher range modules. This modules outputs Analog voltage (0-5V) based on the current flowing through the wire; hence it is very easy to interface this module with any microcontroller. So if you are looking for a module to measure current using a microcontroller for you project then this module might be the right choice for you.

The ACS712 module has two phoenix terminal connectors (green colour ones) with mounting screws as shown above. These are the terminals through which the wire has to be passed. In our case I am measuring the current drawn by the motor so the wires that is going to the load (motor) is passed through the ACS 712 Module. Make sure the module is connected in series with the load and be extra cautious to avoid shorts.

On the other side we have three pins. The Vcc is connected to +5V to power the module and the ground is connected to the ground of the MCU (system). Then the analog voltage given out by the ACS712 module is read using any analog pin on the Microcontroller.

By default when no current is flowing through the module terminals the output voltage will be +2.5V (Vcc/2), when the current flows in one direction the value will increase from 2.5V and when it flows in other direction the values will decrease from 2.5V. This way the module enables us to measure both AC current and DC current. Let us assume that the microcontroller you are using has a 10-bit ADC and operates at 5V with a reference voltage of 5V for ADC conversion in that case the microcontroller will read the values of ADC from 0 to 1024. Then you can use the formulae below to calculate the Output Voltage from ADC values.

Allegro MicroSystems, LLC is a leader in developing, manufacturing and marketing high-performance semiconductors. Allegro's innovative solutions serve high-growth applications within the automotive market, with additional focus on office automation, industrial, and consumer/communications solutions. Allegro is headquartered in Worcester, Massachusetts (USA) with design, applications, and sales support centers located worldwide.

Download datasheets and manufacturer documentation for Allegro MicroSystems ACS712ELCTR-20A-T.