ACS756

ACS756
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ACS756

Product catalog summary
Overview: The ACS756 is a Hall Effect-based linear current sensor IC designed for precise AC or DC current sensing in systems such as industrial, automotive, and communications. It provides an analog output voltage proportional to the current flowing through its primary conductor.
Specifications: The device operates with a supply voltage between 3.0 to 5.0 V, featuring a low internal resistance of 130 μΩ to minimize power loss. It offers a high isolation voltage of 3 kVRMS and can handle overcurrent conditions up to 5 times its rated capacity.
Features and Benefits: The ACS756 offers industry-leading noise performance, a compact package for easy mounting, and a monolithic Hall IC for high reliability. It is factory-trimmed for accuracy and provides stable output with minimal magnetic hysteresis.
Performance Characteristics: Sensitivity varies with temperature and current range, with typical values of 20 or 40 mV/A. It maintains a total output error of 0.8% at 25°C and features a fast response time of 3 μs to step input currents.
Applications: Typical applications include motor control, load detection, power supplies, and overcurrent protection. The design allows for electrical isolation without additional components like opto-isolators.
Absolute Maximum Ratings: The ACS756 can handle a forward supply voltage of up to 8 V and a reverse supply voltage of -0.5 V. It operates within a temperature range of -40°C to 125°C, with a maximum junction temperature of 165°C.
Accuracy Characteristics: Accuracy is defined by sensitivity, noise, nonlinearity, and total output error. It features a ratiometric output, meaning its output voltage and sensitivity are proportional to the supply voltage.
Dynamic Response Characteristics: Key dynamic response characteristics include propagation delay, rise time, and power-on time. Propagation delay is the time for the device output to reflect a change in the primary current signal. Rise time is the interval to reach from 10% to 90% of its full-scale value, used to derive bandwidth. Power-on time is the time for the output voltage to stabilize within ±10% of its steady state after the power supply reaches its minimum operating voltage.
Chopper Stabilization Technique: This patented technique minimizes offset voltage in Hall elements and associated amplifiers, involving modulation-demodulation processes to suppress undesired DC offset signals, resulting in stable electrical offset voltage and immunity to thermal stress.
Package and Layout: Details are provided for the package CA, 5-pin package, leadform PFF, including dimensions and branding information. A PCB layout reference view and notes on branding scale and appearance are included.
Revision History: A revision (Rev. 6) dated March 25, 2011, augmented the VCC specification.
Legal and Usage Notes: Allegro MicroSystems reserves the right to make changes to improve performance, reliability, or manufacturability. The products are not intended for use in life support devices where failure could affect safety or effectiveness. Users are advised to verify the currency of the information before placing orders.
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Catalog excerpts

ACS756-1

ACS756 Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 3 kVRMS Voltage Isolation and a Low-Resistance Current Conductor Features and Benefits ▪ Industry-leading noise performance through proprietary amplifier and filter design techniques ▪ Total output error 0.8% at TA = 25°C ▪ Small package size, with easy mounting capability ▪ Monolithic Hall IC for high reliability ▪ Ultra-low power loss: 130 μΩ internal conductor resistance ▪ 3 kVRMS minimum isolation voltage from pins 1-3 to pins 4-5 ▪ 3.0 to 5.0 V, single supply operation ▪ 3 μs output rise time in response to step input current ▪ 20 or 40 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 The Allegro ACS756 family of current sensor ICs provides economical and precise solutions for AC or DC current sensing in industrial, automotive, commercial, and communications systems. The device package allows for easy implementation by the customer. Typical applications include motor control, load detection and management, power supplies, and overcurrent fault protection. The device consists of a precision, low-offset linear Hall circuit with a copper conduction path located near the die. Applied current flowing through this copper conduction path generates a magnetic field which the Hall IC converts into a proportional voltage. Device accuracy is optimized through the close proximity of the magnetic signal to the Hall transducer. A precise, proportional voltage is provided by the low-offset, chopper-stabilized BiCMOS Hall IC, which is programmed for accuracy at the factory. The output of the device has a positive slope (>VCC / 2) when an increasing current flows through the primary copper conduction path (from terminal 4 to terminal 5), which is the path used for current sampling. The internal resistance of this conductive path is 130 μΩ typical, providing low power loss. Package: 5 pin package (suffix PFF) The thickness of the copper conductor allows survival of the device at up to 5× overcurrent conditions. The terminals of the 1 Continued on the next page… Additional leadforms available for qualifying volumes Typical Application Application 1. The ACS756 outputs an analog signal, VOUT , that varies linearly with the uni- or bi-directional AC or DC primary sampled current, IP , within the range specified. CF is for optimal noise management, with values that depend on the application.

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ACS756-2

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 3 kVRMS Voltage Isolation and a Low-Resistance Current Conductor Description (continued) conductive path are electrically isolated from the signal leads (pins 1 through 3). This allows the ACS756 family of sensor ICs to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques. The device is fully calibrated prior to shipment from the factory. The ACS75x family is lead (Pb) free. All leads are plated with 100% matte tin, and there is no Pb inside the package. The...

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ACS756-3

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 3 kVRMS Voltage Isolation and a Low-Resistance Current Conductor Functional Block Diagram +5 V VCC Dynamic Offset Cancellation Temperature Coefficient Terminal List Table Number Device power supply terminal Signal ground terminal Terminal for current being sampled Terminal for current being sampled Analog output signal Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com

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ACS756-4

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 3 kVRMS Voltage Isolation and a Low-Resistance Current Conductor COMMON OPERATING CHARACTERISTICS1 over full range of TOP, and VCC = 5 V, unless otherwise specified Characteristic Supply Test Conditions Supply Current IP = three-quarter scale of IP+, TA = 25°C, COUT = 0.47 nF Rise Time Internal –3 dB; IP is 10 A peak-to-peak; 100 pF from VIOUT to GND Output Load Resistance Output Load Capacitance Primary Conductor Resistance Symmetry Bidirectional 0 A Output Magnetic Offset Error RPRIMARY ESYM VOUT(QBI) IERROM Propagation Time...

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ACS756-5

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 3 kVRMS Voltage Isolation and a Low-Resistance Current Conductor X050 PERFORMANCE CHARACTERISTICS over Range K1: Characteristic Primary Sampled Current Sensitivity Noise2 TOP = –40°C to 125°C, VCC = 5 V, unless otherwise specified Test Conditions SensTA SensTOP Half scale of IP applied for 5 ms, TA = 25°C Half scale of IP applied for 5 ms Up to full scale of IP , IP applied for 5 ms, TOP = 25°C to 125°C Up to full scale of IP , IP applied for 5 ms, TOP = –40°C to 25°C ELIN(HT) VOE(TA) Over full scale of IP , IP applied for 5 ms,...

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ACS756-6

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 3 kVRMS Voltage Isolation and a Low-Resistance Current Conductor X100 PERFORMANCE CHARACTERISTICS over Range S1: Characteristic Primary Sampled Current Sensitivity Noise2 TOP = –20°C to 85°C, VCC = 5 V, unless otherwise specified Test Conditions SensTA SensTOP Half scale of IP applied for 5 ms, TA = 25°C Half scale of IP applied for 5 ms Up to full scale of IP , IP applied for 5 ms, TOP = 25°C to 85°C Up to full scale of IP , IP applied for 5 ms, TOP = –20°C to 25°C VOE(TOP)LT IP = 0 A, TOP = –20°C to 25°C Total Output Error4 Over...

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ACS756-7

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 3 kVRMS Voltage Isolation and a Low-Resistance Current Conductor Definitions of Accuracy Characteristics Sensitivity (Sens). The change in device output in response to a 1 A change through the primary conductor. The sensitivity is the product of the magnetic circuit sensitivity (G / A) and the linear IC amplifier gain (mV/G). The linear IC amplifier gain is programmed at the factory to optimize the sensitivity (mV/A) for the half-scale current of the device. Noise (VNOISE). The noise floor is derived from the thermal and shot noise...

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