ACS712

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IP– IP– IP 5GND ACS712 +5 V VIOUT VOUT 6FILTER VCC CBYP 0.1 μF CF 1 nF that varies linearly with the uni- or bi-directional AC or DC primary sampled current, I P , within the range specified. CF is recommended for noise management, with values that depend on the application. ACS712

Description

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, switch- mode power supplies, and overcurrent fault protection. The device is not intended for automotive applications. The device consists of a precise, low-offset, linear Hall circuit with a copper conduction path located near the surface of 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 after packaging. The output of the device has a positive slope (>V IOUT(Q)) when an increasing current flows through the primary copper conduction path (from pins 1 and 2, to pins 3 and 4), which is the path used for current sampling. The internal resistance of this conductive path is 1.2 mΩ typical, providing low power loss. The thickness of the copper conductor allows survival of ACS712-DS, Rev. 13 Features and Benefits ▪ 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 T A = 25°C ▪ Small footprint, low-profile SOIC8 package ▪ 1.2 m Ω 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 Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current Conductor Continued on the next page… Approximate Scale 1:1 Package: 8 Lead SOIC (suffix LC) Typical Application TÜV America Certificate Number: U8V 06 05 54214 010

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 2Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A. Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Supply Voltage V CC 8V Reverse Supply Voltage V RCC –0.1 V Output Voltage V IOUT 8V Reverse Output Voltage V RIOUT –0.1 V Reinforced Isolation Voltage V ISO Pins 1-4 and 5-8; 60 Hz, 1 minute, TA=25°C 2100 VAC Maximum working voltage according to UL60950-1 184 V peak Basic Isolation Voltage V ISO(bsc) Pins 1-4 and 5-8; 60 Hz, 1 minute, TA=25°C 1500 VAC Maximum working voltage according to UL60950-1 354 V peak Output Current Source I IOUT(Source) 3m A Output Current Sink I IOUT(Sink) 10 mA Overcurrent Transient Tolerance I P 1 pulse, 100 ms 100 A Nominal Operating Ambient Temperature T A Range E –40 to 85 ºC Maximum Junction Temperature T J(max) 165 ºC Storage Temperature T stg –65 to 170 ºC Selection Guide Part Number Packing* TA (°C) Optimized Range, IP (A) Sensitivity, Sens (Typ) (mV/A) ACS712ELCTR-05B-T Tape and reel, 3000 pieces/reel –40 to 85 ±5 185 ACS712ELCTR-20A-T Tape and reel, 3000 pieces/reel –40 to 85 ±20 100 ACS712ELCTR-30A-T Tape and reel, 3000 pieces/reel –40 to 85 ±30 66 *Contact Allegro for additional packing options. the device at up to 5× overcurrent conditions. The terminals of the conductive path are electrically isolated from the signal leads (pins 5 through 8). This allows the ACS712 to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques. The ACS712 is provided in a small, surface mount SOIC8 package. The leadframe is plated with 100% matte tin, which is compatible with standard lead (Pb) free printed circuit board assembly processes. Internally, the device is Pb-free, except for flip-chip high-temperature Pb-based solder balls, currently exempt from RoHS. The device is fully calibrated prior to shipment from the factory. Description (continued) Parameter Specification Fire and Electric Shock CAN/CSA-C22.2 No. 60950-1-03 UL 60950-1:2003 EN 60950-1:2001

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 3Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. VCC (Pin 8) (Pin 7) VIOUT RF(INT) GND (Pin 5) FILTER (Pin 6) Dynamic Offset Cancellation IP+ (Pin 1) IP+ (Pin 2) IP− (Pin 3) IP− (Pin 4) Sense Trim Signal Recovery Sense Temperature Coefficient Trim

0 Ampere

+5 V IP+ IP+ IP– IP– VCC VIOUT FILTER GND Terminal List Table Number Name Description 1 and 2 IP+ Terminals for current being sampled; fused internally 3 and 4 IP– Terminals for current being sampled; fused internally

5 GND Signal ground terminal

6 FILTER Terminal for external capacitor that sets bandwidth

7 VIOUT Analog output signal

8 VCC Device power supply terminal

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 4Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. COMMON OPERATING CHARACTERISTICS1 over full range of TA , CF = 1 nF, and VCC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. Max. Units

ELECTRICAL CHARACTERISTICS

Supply Voltage V CC 4.5 5.0 5.5 V Supply Current I CC VCC = 5.0 V, output open – 10 13 mA Output Capacitance Load C LOAD VIOUT to GND – – 10 nF Output Resistive Load R LOAD VIOUT to GND 4.7 – – k Ω Primary Conductor Resistance R PRIMARY TA = 25°C – 1.2 – m Ω Rise Time t r IP = IP(max), TA = 25°C, COUT = open – 5 – μs Frequency Bandwidth f –3 dB, T A = 25°C; IP is 10 A peak-to-peak – 80 – kHz Nonlinearity E LIN Over full range of IP – 1.5 – % Symmetry E SYM Over full range of IP 98 100 102 % Zero Current Output Voltage V IOUT(Q) Bidirectional; IP = 0 A, TA = 25°C – VCC × 0.5 –V Power-On Time t PO Output reaches 90% of steady-state level, TJ = 25°C, 20 A present on leadframe –3 5– μs Magnetic Coupling2 – 12 – G/A Internal Filter Resistance3 RF(INT) 1.7 k Ω 1Device may be operated at higher primary current levels, IP, and ambient, TA , and internal leadframe temperatures, TA , provided that the Maximum Junction Temperature, TJ(max), is not exceeded. 21G = 0.1 mT. 3RF(INT) forms an RC circuit via the FILTER pin. COMMON THERMAL CHARACTERISTICS1 Min. Typ. Max. Units Operating Internal Leadframe Temperature T A E range –40 – 85 °C Value Units Junction-to-Lead Thermal Resistance2 RθJL Mounted on the Allegro ASEK 712 evaluation board 5 °C/W Junction-to-Ambient Thermal Resistance R θJA Mounted on the Allegro 85-0322 evaluation board, includes the power con- sumed by the board 23 °C/W 1Additional thermal information is available on the Allegro website. 2The Allegro evaluation board has 1500 mm2 of 2 oz. copper on each side, connected to pins 1 and 2, and to pins 3 and 4, with thermal vias connect- ing the layers. Performance values include the power consumed by the PCB. Further details on the board are available from the Frequently Asked Questions document on our website. Further information about board design and thermal performance also can be found in the Applications Informa- tion section of this datasheet.

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 5Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. x05B PERFORMANCE CHARACTERISTICS1 TA = –40°C to 85°C, CF = 1 nF, and VCC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. Max. Units Optimized Accuracy Range I P –5 – 5 A Sensitivity Sens Over full range of I P, TA = 25°C 180 185 190 mV/A Noise V NOISE(PP) Peak-to-peak, TA = 25°C, 185 mV/A programmed Sensitivity, CF = 47 nF, COUT = open, 2 kHz bandwidth –2 1– m V Zero Current Output Slope ∆IOUT(Q) TA = –40°C to 25°C – –0.26 – mV/°C TA = 25°C to 150°C – –0.08 – mV/°C Sensitivity Slope ∆Sens TA = –40°C to 25°C – 0.054 – mV/A/°C TA = 25°C to 150°C – –0.008 – mV/A/°C Total Output Error2 ETOT IP =±5 A, TA = 25°C – ±1.5 – % 1Device may be operated at higher primary current levels, IP, and ambient temperatures, TA, provided that the Maximum Junction Temperature, TJ(max), is not exceeded. 2Percentage of IP, with IP = 5 A. Output filtered. x20A PERFORMANCE CHARACTERISTICS1 TA = –40°C to 85°C, CF = 1 nF, and VCC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. Max. Units Optimized Accuracy Range I P –20 – 20 A Sensitivity Sens Over full range of I P, TA = 25°C 96 100 104 mV/A Noise V NOISE(PP) Peak-to-peak, TA = 25°C, 100 mV/A programmed Sensitivity, CF = 47 nF, COUT = open, 2 kHz bandwidth –1 1– m V Zero Current Output Slope ∆IOUT(Q) TA = –40°C to 25°C – –0.34 – mV/°C TA = 25°C to 150°C – –0.07 – mV/°C Sensitivity Slope ∆Sens TA = –40°C to 25°C – 0.017 – mV/A/°C TA = 25°C to 150°C – –0.004 – mV/A/°C Total Output Error2 ETOT IP =±20 A, TA = 25°C – ±1.5 – % 1Device may be operated at higher primary current levels, IP, and ambient temperatures, TA, provided that the Maximum Junction Temperature, TJ(max), is not exceeded. 2Percentage of IP, with IP = 20 A. Output filtered. x30A PERFORMANCE CHARACTERISTICS1 TA = –40°C to 85°C, CF = 1 nF, and VCC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. Max. Units Optimized Accuracy Range I P –30 – 30 A Sensitivity Sens Over full range of I P , TA = 25°C 63 66 69 mV/A Noise V NOISE(PP) Peak-to-peak, TA = 25°C, 66 mV/A programmed Sensitivity, CF = 47 nF, COUT = open, 2 kHz bandwidth –7– m V Zero Current Output Slope ∆IOUT(Q) TA = –40°C to 25°C – –0.35 – mV/°C TA = 25°C to 150°C – –0.08 – mV/°C Sensitivity Slope ∆Sens TA = –40°C to 25°C – 0.007 – mV/A/°C TA = 25°C to 150°C – –0.002 – mV/A/°C Total Output Error2 ETOT IP = ±30 A , TA = 25°C – ±1.5 – % 1Device may be operated at higher primary current levels, IP, and ambient temperatures, TA, provided that the Maximum Junction Temperature, TJ(max), is not exceeded. 2Percentage of IP, with IP = 30 A. Output filtered.

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 6Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. –40 150 TA (°C) –40 150 TA (°C) IP = 0 A IP = 0 A VCC = 5 V VCC = 5 V VCC = 5 V VCC = 5 V; IP = 0 A, After excursion to 20 A Mean Supply Current versus Ambient Temperature Sensitivity versus Sensed Current 200.00 190.00 180.00 170.00 160.00 150.00 140.00 130.00 120.00 110.00 100.00 Sens (mV/A) 186.5 186.0 185.5 185.0 184.5 184.0 183.5 183.0 182.5 182.0 181.5 181.0 Sens (mV/A) Ip (A) - 6 - 4 - 20246 TA (°C) TA (°C) TA (°C) Mean ICC (mA) 10.30 10.25 10.20 10.15 10.10 10.05 10.00 9.95 9.90 9.85 9.80 9.75 -50 -25 0 25 50 75 125 100 150 IOM (mA) –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 –3.5 –4.0 –4.5 –5.0 -50 -25 0 25 50 75 125 100 150 Supply Current versus Supply Voltage 10.9 10.8 10.7 10.6 10.5 10.4 10.3 10.2 10.1 10.0 VCC (V) ICC (mA) TA (°C) VIOUT(Q) (mV) 2520 2515 2510 2505 2500 2495 2490 2485 -50 -25 0 25 50 75 125 100 150 TA (°C) IOUT(Q) (A) 0.20 0.15 0.10 0.05 –0.05 –0.10 –0.15 -50 -25 0 25 50 75 125 100 150 Nonlinearity versus Ambient Temperature 0.6 0.5 0.4 0.3 0.2 0.1 –50 0 –25 25 50 12575 100 150 ELIN (%) TA (°C) Mean Total Output Error versus Ambient Temperature –50 0 –25 25 50 12575 100 150 ETOT (%) TA (°C) Sensitivity versus Ambient Temperature –50 0 –25 25 50 12575 100 150 IP (A) Output Voltage versus Sensed Current 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 VIOUT (V) Magnetic Offset versus Ambient Temperature VCC = 5 V

0 A Output Voltage versus Ambient Temperature 0 A Output Voltage Current versus Ambient Temperature

Characteristic Performance IP = 5 A, unless otherwise specified

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 7Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. –40 150 TA (°C) –40 –20 125 TA (°C) IP = 0 A IP = 0 A VCC = 5 V VCC = 5 V VCC = 5 V VCC = 5 V; IP = 0 A, After excursion to 20 A Mean Supply Current versus Ambient Temperature Sensitivity versus Sensed Current 110.00 108.00 106.00 104.00 102.00 100.00 98.00 96.00 94.00 92.00 90.00 Sens (mV/A) Ip (A) TA (°C) TA (°C) Mean ICC (mA) 9.7 9.6 9.5 9.4 9.3 9.2 9.1 -50 -25 0 25 50 75 125 100 150 Supply Current versus Supply Voltage 10.4 10.2 10.0 9.8 9.6 9.4 9.2 9.0 VCC (V) ICC (mA) Nonlinearity versus Ambient Temperature 0.35 0.30 0.25 0.20 0.15 0.10 0.05 –50 0 –25 25 50 12575 100 150 ELIN (%) TA (°C) Mean Total Output Error versus Ambient Temperature –50 0 –25 25 50 12575 100 150 ETOT (%) IP (A) Output Voltage versus Sensed Current 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 –25 –20 –15 –10 –5 0 5 1 01 52 02 5 VIOUT (V) –25 –20 –15 –10 –5 0 51 0 1 5 20 25 100.8 100.6 100.4 100.2 100.0 99.8 99.6 99.4 99.2 99.0 Sens (mV/A) TA (°C) Sensitivity versus Ambient Temperature –50 0 –25 25 50 12575 100 150 TA (°C) IOM (mA) –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 –3.5 –4.0 –4.5 –5.0 -50 -25 0 25 50 75 125 100 150 Magnetic Offset versus Ambient Temperature

0 A Output Voltage versus Ambient Temperature

TA (°C) VIOUT(Q) (mV) 2525 2520 2515 2510 2505 2500 2495 2490 2485 -50 -25 0 25 50 75 125 100 150

0 A Output Voltage Current versus Ambient Temperature

TA (°C) IOUT(Q) (A) 0.25 0.20 0.15 0.10 0.05 –0.05 –0.10 –0.15 -50 -25 0 25 50 75 125 100 150 Characteristic Performance IP = 20 A, unless otherwise specified

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 8Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. Characteristic Performance IP = 30 A, unless otherwise specified –40 150 TA (°C)–40 –20 125 TA (°C) IP = 0 A IP = 0 A VCC = 5 V VCC = 5 V VCC = 5 V VCC = 5 V; IP = 0 A, After excursion to 20 A VCC = 5 V Mean Supply Current versus Ambient Temperature Sensitivity versus Sensed Current 70.00 69.00 68.00 67.00 66.00 65.00 64.00 63.00 62.00 61.00 60.00 Sens (mV/A) Ip (A) TA (°C) TA (°C) Mean ICC (mA) 9.6 9.5 9.4 9.3 9.2 9.1 9.0 8.9 -50 -25 0 25 50 75 125 100 150 Supply Current versus Supply Voltage 10.2 10.0 9.8 9.6 9.4 9.2 9.0 VCC (V) ICC (mA) Nonlinearity versus Ambient Temperature 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 –50 0–25 25 50 12575 100 150 ELIN (%) TA (°C) Mean Total Output Error versus Ambient Temperature –50 0 –25 25 50 12575 100 150 ETOT (%) IP (A) Output Voltage versus Sensed Current 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 –30 –20 –10 0 10 20 30 VIOUT (V) –30 –20 –10 0 10 20 30 66.6 66.5 66.4 66.3 66.2 66.1 66.0 65.9 65.8 65.7 Sens (mV/A) TA (°C) Sensitivity versus Ambient Temperature –50 0 –25 25 50 12575 100 150 TA (°C) IOM (mA) –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 –3.5 –4.0 –4.5 –5.0 -50 -25 0 25 50 75 125 100 150 Magnetic Offset versus Ambient Temperature TA (°C) VIOUT(Q) (mV) 2535 2530 2525 2520 2515 2510 2505 2500 2495 2490 2485 -50 -25 0 25 50 75 125 100 150 TA (°C) IOUT(Q) (A) 0.35 0.30 0.25 0.20 0.15 0.10 0.05 –0.05 –0.10 –0.15 -50 -25 0 25 50 75 125 100 150

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 9Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. 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 pro- grammed at the factory to optimize the sensitivity (mV/A) for the full-scale current of the device. Noise (V NOISE). The product of the linear IC amplifier gain (mV/G) and the noise floor for the Allegro Hall effect linear IC (≈1 G). The noise floor is derived from the thermal and shot noise observed in Hall elements. Dividing the noise (mV) by the sensitivity (mV/A) provides the smallest current that the device is able to resolve. Linearity (E LIN). The degree to which the voltage output from the IC varies in direct proportion to the primary current through its full-scale amplitude. Nonlinearity in the output can be attrib- uted to the saturation of the flux concentrator approaching the full-scale current. The following equation is used to derive the linearity: where V IOUT_full-scale amperes = the output voltage (V) when the sampled current approximates full-scale ±IP . Symmetry (ESYM). The degree to which the absolute voltage output from the IC varies in proportion to either a positive or negative full-scale primary current. The following formula is used to derive symmetry: Quiescent output voltage (V IOUT(Q)). The output of the device when the primary current is zero. For a unipolar supply voltage, it nominally remains at VCC ⁄ 2. Thus, VCC = 5 V translates into VIOUT(Q) = 2.5 V . Variation in VIOUT(Q) can be attributed to the resolution of the Allegro linear IC quiescent voltage trim and thermal drift. Electrical offset voltage (V OE). The deviation of the device out- put from its ideal quiescent value of VCC / 2 due to nonmagnetic causes. To convert this voltage to amperes, divide by the device sensitivity, Sens. Accuracy (E TOT). The accuracy represents the maximum devia- tion of the actual output from its ideal value. This is also known as the total output error. The accuracy is illustrated graphically in the output voltage versus current chart at right. Accuracy is divided into four areas:  0 A at 25°C. Accuracy at the zero current flow at 25°C, with- out the effects of temperature.  0 A over Δ temperature. Accuracy at the zero current flow including temperature effects.  Full-scale current at 25°C. Accuracy at the the full-scale current at 25°C, without the effects of temperature.  Full-scale current over Δ temperature. Accuracy at the full- scale current flow including temperature effects. Ratiometry. The ratiometric feature means that its 0 A output, V IOUT(Q), (nominally equal to VCC/2) and sensitivity, Sens, are proportional to its supply voltage, VCC . The following formula is used to derive the ratiometric change in 0 A output voltage, IOUT(Q)RAT (%). The ratiometric change in sensitivity, SensRAT (%), is defined as: Definitions of Accuracy Characteristics 100 1– [{ [ { VIOUT_full-scale amperes – VIOUT(Q)Δ gain × % sat ( ) 2 (VIOUT_half-scale amperes – VIOUT(Q) ) 100 VIOUT_+ full-scale amperes – VIOUT(Q) VIOUT(Q) – VIOUT_–full-scale amperes 100 VIOUT(Q)VCC / VIOUT(Q)5V VCC / 5 V 100 SensVCC / Sens5V VCC / 5 V‰ /c144 Output Voltage versus Sampled Current Accuracy at 0 A and at Full-Scale Current Increasing VIOUT (V) +IP (A) Accuracy Accuracy Accuracy 25°C Only Accuracy 25°C Only Accuracy 25°C Only Accuracy 0 A vrOe $Temp erature Average VIOUT –IP (A) vrOe $Temp erature vrOe $Temp erature Decreasing VIOUT (V) IP(min) IP(max) Full Scale

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 10Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. Power on Time versus External Filter Capacitance 100 120 140 160 180 200 01 0 2 0 3 0 4 0 5 0 CF (nF) CF (nF) tPO (μs) IP = 5 A IP = 0 A Noise versus External Filter Capacitance 1000 100 10000 0.01 0.1 1 10 100 1000 Noise(p-p) (mA) Noise vs. Filter Cap 400 350 300 250 200 150 100 05 0 25 75 100 125 150 tr(μs) CF (nF) Rise Time versus External Filter CapacitanceRise Time versus External Filter Capacitance 200 400 600 800 1000 1200 0 100 200 300 400 500 tr(μs) CF (nF) Expanded in chart at right Definitions of Dynamic Response Characteristics Primary Current Transducer Output I (%) Rise Time, tr t Rise time (tr). The time interval between a) when the device reaches 10% of its full scale value, and b) when it reaches 90% of its full scale value. The rise time to a step response is used to derive the bandwidth of the device, in which ƒ(–3 dB) = 0.35 / t Both tr and tRESPONSE are detrimentally affected by eddy current losses observed in the conductive IC ground plane. Excitation Signal Output (mV) 15 A Step Response TA=25°C CF (nF) t r (μs) 0 6.6 1 7.7 4.7 17.4 10 32.1 22 68.2 47 88.2 100 291.3 220 623.0 470 1120.0 Power-On Time (tPO). When the supply is ramped to its operat- ing voltage, the device requires a finite time to power its internal components before responding to an input magnetic field. Power-On Time, t PO , is defined as the time it takes for the output voltage to settle within ±10% of its steady state value under an applied magnetic field, after the power supply has reached its minimum specified operating voltage, V CC(min), as shown in the chart at right.

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 11Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. Chopper Stabilization is an innovative circuit technique that is used to minimize the offset voltage of a Hall element and an asso- ciated on-chip amplifier. Allegro patented a Chopper Stabiliza- tion technique that nearly eliminates Hall IC output drift induced by temperature or package stress effects. This offset reduction technique is based on a signal modulation-demodulation process. Modulation is used to separate the undesired DC offset signal from the magnetically induced signal in the frequency domain. Then, using a low-pass filter, the modulated DC offset is sup- pressed while the magnetically induced signal passes through the filter. As a result of this chopper stabilization approach, the output voltage from the Hall IC is desensitized to the effects of temperature and mechanical stress. This technique produces devices that have an extremely stable Electrical Offset V oltage, are immune to thermal stress, and have precise recoverability after temperature cycling. This technique is made possible through the use of a BiCMOS process that allows the use of low-offset and low-noise amplifiers in combination with high-density logic integration and sample and hold circuits. Chopper Stabilization Technique Amp Regulator Clock/Logic Hall Element Sample and Hold Low-Pass Filter Concept of Chopper Stabilization Technique

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 12Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. IP+ IP+ IP– IP– IP +5 V LMV7235 VIOUT VOUT GND FILTER VCC ACS712 1N914 100 kΩ 33 kΩ RPU 100 kΩ Fault CBYP 0.1 μF CF 1 nF IP+ IP+ IP– IP– +5 V LT1178 2N7002 VIOUT VOUT VPEAK VRESET GND 1N914 VCC ACS712 10 kΩ 1 MΩ 33 kΩ RF 10 kΩ 330 kΩ CBYP 0.1 μF 0.1 μF COUT 0.1 μF CF 1 nF 0.1 μF FILTER IP IP+ IP+ IP– IP– IP +5 V 1N4448W VIOUT VOUT GND

3 FILTER

10 kΩ CBYP 0.1 μF RF 2 kΩ CF 1 nF A-to-D Converter Typical Applications Application 5. 10 A Overcurrent Fault Latch. Fault threshold set by R1 and R2. This circuit latches an overcurrent fault and holds it until the 5 V rail is powered down. Application 2. Peak Detecting Circuit Application 4. Rectified Output. 3.3 V scaling and rectification application for A-to-D converters. Replaces current transformer solutions with simpler ACS circuit. C1 is a function of the load resistance and filtering desired. R1 can be omitted if the full range is desired. –IP+ IP+ IP– IP– IP +5 V LM321 VIOUT VOUT GND 1 4 FILTER VCC ACS712 100 kΩ 100 kΩ 3.3 kΩ CBYP 0.1 μF CF 0.01 μF 1000 pF RF 1 kΩ Application 3. This configuration increases gain to 610 mV/A (tested using the ACS712ELC-05A).

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 13Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. Improving Sensing System Accuracy Using the FILTER Pin In low-frequency sensing applications, it is often advantageous to add a simple RC filter to the output of the device. Such a low- pass filter improves the signal-to-noise ratio, and therefore the resolution, of the device output signal. However, the addition of an RC filter to the output of a sensor IC can result in undesirable device output attenuation — even for DC signals. Signal attenuation, ∆V ATT , is a result of the resistive divider effect between the resistance of the external filter, RF (see Application 6), and the input impedance and resistance of the customer interface circuit, R INTFC. The transfer function of this resistive divider is given by: Even if RF and RINTFC are designed to match, the two individual resistance values will most likely drift by different amounts over temperature. Therefore, signal attenuation will vary as a function of temperature. Note that, in many cases, the input impedance, R INTFC , of a typical analog-to-digital converter (ADC) can be as low as 10 kΩ. The ACS712 contains an internal resistor, a FILTER pin connec- tion to the printed circuit board, and an internal buffer amplifier. With this circuit architecture, users can implement a simple RC filter via the addition of a capacitor, C F (see Application 7) from the FILTER pin to ground. The buffer amplifier inside of the ACS712 (located after the internal resistor and FILTER pin connection) eliminates the attenuation caused by the resistive divider effect described in the equation for ∆V ATT. Therefore, the ACS712 device is ideal for use in high-accuracy applications that cannot afford the signal attenuation associated with the use of an external RC low-pass filter. =∆VATT RINTFC RF + RINTFC VIOUT ⎟⎠ ⎛ . Application 6. When a low pass filter is constructed externally to a standard Hall effect device, a resistive divider may exist between the filter resistor, R F, and the resistance of the customer interface circuit, RINTFC. This resistive divider will cause excessive attenuation, as given by the transfer function for ∆V ATT. Application 7. Using the FILTER pin provided on the ACS712 eliminates the attenuation effects of the resistor divider between R F and RINTFC, shown in Appli- cation 6. Application Interface Circuit Resistive Divider RINTFC Low Pass Filter RFAmp Out VCC +5 V Pin 8 Pin 7 VIOUT Pin 6 N.C. Input GND Pin 5 Filter Dynamic Offset Cancellation IP+ IP+ 0.1 MF Pin 1 Pin 2 IP– IP– Pin 3 Pin 4 Gain Temperature Coefficient Offset Voltage Regulator Trim Control To all subcircuits Input VCC Pin 8 Pin 7 VIOUT GND Pin 5 FILTER Pin 6 Dynamic Offset Cancellation IP+ Pin 1 IP+ Pin 2 IP– Pin 3 IP– Pin 4 Sense Trim Signal Recovery Sense Temperature Coefficient Trim +5 V Application Interface Circuit Buffer Amplifier and Resistor RINTFC Allegro ACS712 Allegro ACS706 CF 1 nF CF 1 nF

Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Isolation and a Low-Resistance Current ConductorACS712 14Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. Package LC, 8-pin SOIC Copyright ©2006-2010, Allegro MicroSystems, Inc. The products described herein are protected by U.S. patents: 5,621,319; 7,598,601; and patent pending. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec i fi ca tions as may be required to per- mit improvements in the per for mance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. Allegro’s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system. The in for ma tion in clud ed herein is believed to be ac cu rate and reliable. How ev er, Allegro MicroSystems, Inc. assumes no re spon si bil i ty for its use; nor for any in fringe ment of patents or other rights of third parties which may result from its use. For the latest version of this document, visit our website: www.allegromicro.com C SEATING PLANE

1.27 BSC

A Terminal #1 mark area B Reference land pattern layout (reference IPC7351 SOIC127P600X175-8M); all pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances B D C Branding scale and appearance at supplier discretion C SEATING PLANEC0.10

0.25 BSC

1.04 REF

1.75 MAX

For Reference Only; not for tooling use (reference MS-012AA) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown 4.90 ±0.10 0.51 0.31 0.25 0.10 0.25 0.17 1.27 0.40 N = Device part number P = Package Designator T = Device temperature range A = Amperage L = Lot number Belly Brand = Country of Origin NNNNNNN LLLLL PPT-AAA A Standard Branding Reference View PCB Layout Reference ViewC 0.65 1.27 5.60 1.75 Branded Face