ACS724. Automotive-Grade, Galvanically Isolated Current Sensor IC With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package ACS724

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1 FEATURES AND BENEFITS AEC-Q qualified Differential Hall sensing rejects common-mode fields. mω primary conductor resistance for low power loss and high inrush current withstand capability Integrated shield virtually eliminates capacitive coupling from current conductor to die, greatly suppressing output noise due to high dv/dt transients Industry-leading noise performance with greatly improved bandwidth through proprietary amplifier and filter design techniques High-bandwidth khz analog output for faster response times in control applications Filter pin allows user to filter the output for improved resolution at lower bandwidth Patented integrated digital temperature compensation circuitry allows for near closed loop accuracy over temperature in an open loop sensor Small-footprint, low-profile SOIC8 package suitable for space-constrained applications Filter pin simplifies bandwidth limiting for better resolution at lower frequencies Continued on the next page Package: 8-Pin SOIC (suffix LC) Type tested TÜV America Certificate Number: U8V 5 CB 5 CB Certificate Number: US--A-UL Not to scale DESCRIPTION The Allegro ACS7 current sensor IC is an economical and precise solution for AC or DC current sensing in industrial, automotive, commercial, and communications systems. The small package is ideal for space-constrained applications while also saving costs due to reduced board area. Typical applications include motor control, load detection and management, switched-mode power supplies, and overcurrent fault protection. The device consists of a precise, low-offset, linear Hall sensor 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 is sensed by the integrated Hall IC and converted into a proportional voltage. The current is sensed differentially in order to reject common-mode fields, improving accuracy in magnetically noisy environments. The inherent device accuracy is optimized through the close proximity of the magnetic field 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 when an increasing current flows through the primary copper conduction path (from pins and, to pins and ), which is the path used for current sensing. The internal resistance of this conductive path is. mω typical, providing low power loss. The terminals of the conductive path are electrically isolated from the sensor leads (pins 5 through 8). This allows the ACS7 current sensor IC to be used in high-side current sense applications without the use of high-side differential amplifiers or other costly isolation techniques. Continued on the next page +I P I P I P IP+ IP+ IP IP ACS7 VCC VIOUT FILTER GND C F nf C LOAD C BYPASS. µf The ACS7 outputs an analog signal, V IOUT, that changes proportionally with the bidirectional AC or DC primary sensed current, I P, within the specified measurement range. The FILTER pin can be used to decrease the bandwidth in order to optimize the noise performance. Typical Application ACS7-DS, Rev. 8 MCO-7 January, 8

2 Features and Benefits (continued) 5 V, single supply operation Output voltage proportional to AC or DC current Factory-trimmed sensitivity and quiescent output voltage for improved accuracy Chopper stabilization results in extremely stable quiescent output voltage Nearly zero magnetic hysteresis Ratiometric output from supply voltage Description (continued) The ACS7 is provided in a small, low-profile surface-mount SOIC8 package. The leadframe is plated with % 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. Selection Guide Part Number I PR (A) Sens(Typ) at V CC = 5 V (mv/a) T A ( C) Packing* ACS7LLCTR-5AB-T ±5 ACS7LLCTR-AU-T ACS7LLCTR-AB-T ± ACS7LLCTR-AU-T ACS7LLCTR-AB-T ± to 5 Tape and Reel, pieces per reel ACS7LLCTR-AU-T ACS7LLCTR-AB-T ± 66 ACS7LLCTR-5AB-T ±5 *Contact Allegro for additional packing options.

3 SPECIFICATIONS Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Supply Voltage V CC 6 V Reverse Supply Voltage V RCC. V Output Voltage V IOUT V CC +.5 V Reverse Output Voltage V RIOUT. V Operating Ambient Temperature T A Range L to 5 C Junction Temperature T J (max) 65 C Storage Temperature T stg 65 to 65 C Isolation Characteristics Characteristic Symbol Notes Rating Unit Tested ±5 pulses at /minute in compliance to IEC 6--5 Dielectric Surge Strength Test Voltage V SURGE. µs (rise) / 5 µs (width). 6 V Dielectric Strength Test Voltage V ISO (edition ); production-tested at V ISO for second, in V RMS Agency type-tested for 6 seconds per UL standard 695- accordance with UL 695- (edition ). Maximum approved working voltage for basic (single) V pk or VDC Working Voltage for Basic Isolation V WVBI isolation according to UL 695- (edition ) 97 V rms Clearance D cl Minimum distance through air from IP leads to signal leads.. mm Minimum distance along package body from IP leads to Creepage D cr signal leads.. mm Thermal Characteristics Characteristic Symbol Test Conditions* Value Units Package Thermal Resistance (Junction to Ambient) Package Thermal Resistance (Junction to Lead) R θja *Additional thermal information available on the Allegro website. Mounted on the Allegro 85-7 evaluation board with 8 mm of oz. copper on each side, connected to pins and, and to pins and, with thermal vias connecting the layers. Performance values include the power consumed by the PCB. C/W R θjl Mounted on the Allegro ASEK7 evaluation board. 5 C/W

4 V CC VCC Master Current Supply To All Subcircuits POR Programming Control IP+ IP+ Hall Current Drive Temperature Sensor Sensitivity Control EEPROM and Control Logic Offset Control C BYPASS. µf IP Dynamic Offset Cancellation + R F(int) + VIOUT IP GND C F FILTER Functional Block Diagram Pinout Diagram and Terminal List Table IP+ IP+ IP IP 8 VCC 7 VIOUT 6 FILTER 5 GND Package LC, 8-Pin SOICN Pinout Diagram Terminal List Table Number Name Description, IP+ Terminals for current being sensed; fused internally, IP Terminals for current being sensed; 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

5 COMMON ELECTRICAL CHARACTERISTICS [] : Valid through the full range of T A, V CC = 5 V, C F =, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. Max. Unit Supply Voltage V CC V Supply Current I CC V CC = 5 V, output open ma Output Capacitance Load C L VIOUT to GND nf Output Resistive Load R L VIOUT to GND.7 kω Primary Conductor Resistance R IP T A = 5 C. mω Internal Filter Resistance [] R F(int).8 kω Common Mode Field Rejection Ratio CMFRR Uniform external magnetic field db Primary Hall Coupling Factor G T A = 5 C G/A Secondary Hall Coupling Factor G T A = 5 C.8 G/A Hall Plate Sensitivity Matching Sens match T A = 5 C ± % Rise Time t r I P = I P (max), T A = 5 C, C L = nf μs Propagation Delay t pd I P = I P (max), T A = 5 C, C L = nf μs Response Time t RESPONSE I P = I P (max), T A = 5 C, C L = nf μs Bandwidth BW Small signal db; C L = nf khz Input-referenced noise density; Noise Density I ND T A = 5 C, C L = nf Input-referenced noise: C Noise I F =.7 nf, N C L = nf, BW = 8 khz, T A = 5 C 5 µa (rms) / Hz ma (rms) Nonlinearity E LIN Through full range of I P % Sensitivity Ratiometry Coefficient SENS_RAT_ COEF V CC =.5 to 5.5 V, T A = 5 C. Zero-Current Output Ratiometry Coefficient QVO_RAT_ COEF V CC =.5 to 5.5 V, T A = 5 C V Saturation Voltage [] OH R L =.7 kω V CC. V V OL R L =.7 kω. V Output reaches 9% of steady-state Power-On Time t PO level, T A = 5 C, I P = I PR (max) applied 8 μs Shorted Output-to-Ground Current I SC(GND) T A = 5 C. ma Shorted Output-to-V CC Current I SC(VCC) T A = 5 C 5 ma [] Device may be operated at higher primary current levels, I P, ambient temperatures, T A, and internal leadframe temperatures, provided the Maximum Junction Temperature, T J (max), is not exceeded. [] R F(int) forms an RC circuit via the FILTER pin. [] The sensor IC will continue to respond to current beyond the range of I P until the high or low saturation voltage; however, the nonlinearity in this region will be worse than through the rest of the measurement range. 5

6 xllctr-5ab PERFORMANCE CHARACTERISTICS: T A Range L, valid at T A = C to 5 C, V CC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. [] Max. Unit Nominal Performance Current Sensing Range I PR 5 5 A Sensitivity Sens I PR(min) < I P < I PR(max) mv/a Zero-Current Output Voltage V IOUT(Q) Bidirectional, I P = A Accuracy Performance V CC.5 V Total Output Error [] E TOT I P = I PR(max), T A = 5 C to 5 C.5 ±.5.5 % I P = I PR(max), T A = C to 5 C 6 ±.5 6 % TOTAL Output Error Components [] E TOT = E SENS + V OE /(Sens I P ) Sensitivity Error E sens I P = I PR(max), T A = 5 C to 5 C ± % I P = I PR(max), T A = C to 5 C 5.5 ± % Offset Voltage V OE I P = A, T A = 5 C to 5 C 5 ±7 5 mv I P = A, T A = C to 5 C ± mv Lifetime Drift Characteristics Sensitivity Error Lifetime Drift E sens_drift ± % Total Output Error Lifetime Drift E tot_drift ± % [] Typical values with +/- are sigma values. [] Percentage of I P, with I P = I PR(max). [] A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output error specification. Also, sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section. 6

7 xllctr-au PERFORMANCE CHARACTERISTICS: T A Range L, valid at T A = C to 5 C, V CC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. [] Max. Unit Nominal Performance Current-Sensing Range I PR A Sensitivity Sens I PR(min) < I P < I PR(max) mv/a Zero-Current Output Voltage V IOUT(Q) Unidirectional, I P = A Accuracy Performance V CC. V Total Output Error [] E TOT I P = I PR(max), T A = 5 C to 5 C.5 ±.5.5 % I P = I PR(max), T A = C to 5 C 6 ±.5 6 % TOTAL Output Error Components [] E TOT = E SENS + V OE /(Sens I P ) Sensitivity Error E sens I P = I PR(max), T A = 5 C to 5 C ± % I P = I PR(max), T A = C to 5 C 5.5 ± % Offset Voltage V OE I P = A, T A = 5 C to 5 C 5 ±7 5 mv I P = A, T A = C to 5 C ± mv Lifetime Drift Characteristics Sensitivity Error Lifetime Drift E sens_drift ± % Total Output Error Lifetime Drift E tot_drift ± % [] Typical values with +/- are sigma values. [] Percentage of I P, with I P = I PR(max). [] A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output error specification. Also, sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section. 7

8 xllctr-ab PERFORMANCE CHARACTERISTICS: T A Range L, valid at T A = C to 5 C, V CC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. Max. Unit Nominal Performance Current-Sensing Range I PR A Sensitivity Sens I PR(min) < I P < I PR(max) mv/a Zero-Current Output Voltage V IOUT(Q) Bidirectional, I P = A Accuracy Performance V CC.5 V Total Output Error E TOT I P = I PR(max), T A = 5 C to 5 C ± % I P = I PR(max), T A = C to 5 C 6 ±.5 6 % TOTAL Output Error Components E TOT = E SENS + V OE /(Sens I P ) Sensitivity Error E sens I P = I PR(max), T A = 5 C to 5 C.5 ±.5 % I P = I PR(max), T A = C to 5 C 5.5 ± % Offset Voltage V OE I P = A, T A = 5 C to 5 C ±6 mv I P = A, T A = C to 5 C ±8 mv Lifetime Drift Characteristics Sensitivity Error Lifetime Drift E sens_drift ± % Total Output Error Lifetime Drift E tot_drift ± % [] Typical values with +/- are sigma values. [] Percentage of I P, with I P = I PR(max). [] A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output error specification. Also, sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section. 8

9 xllctr-au PERFORMANCE CHARACTERISTICS: T A Range L, valid at T A = C to 5 C, V CC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. [] Max. Unit Nominal Performance Current-Sensing Range I PR A Sensitivity Sens I PR(min) < I P < I PR(max) mv/a Zero-Current Output Voltage V IOUT(Q) Unidirectional, I P = A Accuracy Performance V CC. V Total Output Error [] E TOT I P = I PR(max), T A = 5 C to 5 C ±.7 % I P = I PR(max), T A = C to 5 C 6 ± 6 % TOTAL Output Error Components [] E TOT = E SENS + V OE /(Sens I P ) Sensitivity Error E sens I P = I PR(max), T A = 5 C to 5 C.5 ±.7.5 % I P = I PR(max), T A = C to 5 C 5.5 ± 5.5 % Offset Voltage V OE I P = A, T A = 5 C to 5 C ±6 mv I P = A, T A = C to 5 C ±8 mv Lifetime Drift Characteristics Sensitivity Error Lifetime Drift E sens_drift ± % Total Output Error Lifetime Drift E tot_drift ± % [] Typical values with +/- are sigma values. [] Percentage of I P, with I P = I PR(max). [] A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output error specification. Also, sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section. 9

10 xllctr-ab PERFORMANCE CHARACTERISTICS: T A Range L, valid at T A = C to 5 C, V CC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. [] Max. Unit Nominal Performance Current-Sensing Range I PR A Sensitivity Sens I PR(min) < I P < I PR(max) mv/a Zero-Current Output Voltage V IOUT(Q) Bidirectional, I P = A Accuracy Performance V CC.5 V Total Output Error [] E TOT I P = I PR(max), T A = 5 C to 5 C ±.8 % I P = I PR(max), T A = C to 5 C 6 ± 6 % TOTAL Output Error Components [] E TOT = E SENS + V OE /(Sens I P ) Sensitivity Error E sens I P = I PR(max), T A = 5 C to 5 C.5 ±.6.5 % I P = I PR(max), T A = C to 5 C 5.5 ± 5.5 % Offset Voltage V OE I P = A, T A = 5 C to 5 C ±5 mv I P = A, T A = C to 5 C ±6 mv Lifetime Drift Characteristics Sensitivity Error Lifetime Drift E sens_drift ± % Total Output Error Lifetime Drift E tot_drift ± % [] Typical values with +/- are sigma values. [] Percentage of I P, with I P = I PR(max). [] A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output error specification. Also, sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.

11 xllctr-au PERFORMANCE CHARACTERISTICS: T A Range L, valid at T A = C to 5 C, V CC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. [] Max. Unit Nominal Performance Current-Sensing Range I PR A Sensitivity Sens I PR(min) < I P < I PR(max) mv/a Zero-Current Output Voltage V IOUT(Q) Unidirectional, I P = A Accuracy Performance V CC. V Total Output Error [] E TOT I P = I PR(max), T A = 5 C to 5 C ±.7 % I P = I PR(max), T A = C to 5 C 6 ± 6 % TOTAL Output Error Components [] E TOT = E SENS + V OE /(Sens I P ) Sensitivity Error E sens I P = I PR(max), T A = 5 C to 5 C.5 ±.7.5 % I P = I PR(max), T A = C to 5 C 5.5 ± 5.5 % Offset Voltage V OE I P = A, T A = 5 C to 5 C ±6 mv I P = A, T A = C to 5 C ±7 mv Lifetime Drift Characteristics Sensitivity Error Lifetime Drift E sens_drift ± % Total Output Error Lifetime Drift E tot_drift ± % [] Typical values with +/- are sigma values. [] Percentage of I P, with I P = I PR(max). [] A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output error specification. Also, sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.

12 xllctr-ab PERFORMANCE CHARACTERISTICS: T A Range L, valid at T A = C to 5 C, V CC = 5 V, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. [] Max. Unit Nominal Performance Current-Sensing Range I PR A Sensitivity Sens I PR(min) < I P < I PR(max) 66 mv/a Zero-Current Output Voltage V IOUT(Q) Bidirectional, I P = A Accuracy Performance V CC.5 V Total Output Error [] E TOT I P = I PR(max), T A = 5 C to 5 C ±.8 % I P = I PR(max), T A = C to 5 C 6 ± 6 % TOTAL Output Error Components [] E TOT = E SENS + V OE /(Sens I P ) Sensitivity Error E sens I P = I PR(max), T A = 5 C to 5 C.5 ±.8.5 % I P = I PR(max), T A = C to 5 C 5.5 ± 5.5 % Offset Voltage V OE I P = A, T A = 5 C to 5 C ±6 mv I P = A, T A = C to 5 C ±6 mv Lifetime Drift Characteristics Sensitivity Error Lifetime Drift E sens_drift ± % Total Output Error Lifetime Drift E tot_drift ± % [] Typical values with +/- are sigma values. [] Percentage of I P, with I P = I PR(max). [] A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output error specification. Also, sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.

13 xllctr-5ab PERFORMANCE CHARACTERISTICS: T A Range L, valid at T A = C to 5 C, V CC = 5 V, C F =, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. [] Max. Unit Nominal Performance Current-Sensing Range I PR 5 5 A Sensitivity Sens I PR(min) < I P < I PR(max) mv/a Zero-Current Output Voltage V IOUT(Q) Bidirectional, I P = A Accuracy Performance V CC.5 V Total Output Error [] E TOT I P = I PR(max), T A = 5 C to 5 C ±.8 % I P = I PR(max), T A = C to 5 C 6 ± 6 % TOTAL Output Error Components [] E TOT = E SENS + V OE /(Sens I P ) Sensitivity Error E sens I P = I PR(max), T A = 5 C to 5 C.5 ±.8.5 % I P = I PR(max), T A = C to 5 C 5.5 ± 5.5 % Offset Voltage V OE I P = A, T A = 5 C to 5 C ±6 mv I P = A, T A = C to 5 C ±6 mv Lifetime Drift Characteristics Sensitivity Error Lifetime Drift E sens_drift ± % Total Output Error Lifetime Drift E tot_drift ± % [] Typical values with +/- are sigma values. [] Percentage of I P, with I P = I PR(max). [] A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output error specification. Also, sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.

14 CHARACTERISTIC PERFORMANCE xllctr-5ab Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature V IOUT(Q) (mv) Temperature ( C) Offset Voltage (mv) Temperature ( C) Sensitivity (mv/a) Sensitivity vs. Temperature Temperature ( C) Sensitivity Error (%) Sensitivity Error vs. Temperature Temperature ( C) Nonlinearity (%) Nonlinearity vs. Temperature Total Error (%) Total Error at I PR(max) vs. Temperature -. Temperature ( C) -8. Temperature ( C) + Sigma Average - Sigma

15 Zero Current Output Voltage vs. Temperature CHARACTERISTIC PERFORMANCE xllctr-au Offset Voltage vs. Temperature V (mv) IOUT(Q) Offset Voltage (mv) Sensitivity vs. Temperature Sensitivity Error vs. Temperature 5 Sensitivity (mv/a) Sensitivity Error (%) Nonlinearity vs. Temperature Total Error at I PR(max) vs. Temperature..8.6 Nonlinearity (%) Total Error (%) Sigma Average - Sigma 5

16 xllctr-ab Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature V (mv) IOUT(Q) Offset Voltage (mv) Sensitivity vs. Temperature Sensitivity Error vs. Temperature Sensitivity (mv/a) Sensitivity Error (%) Nonlinearity vs. Temperature Total Error at I PR(max) vs. Temperature. 5 Nonlinearity (%) Total Error (%) Sigma Average - Sigma 6

17 xllctr-au Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature V (mv) IOUT(Q) Offset Voltage (mv) Sensitivity vs. Temperature Sensitivity Error vs. Temperature 8 6 Sensitivity (mv/a) Sensitivity Error (%) Nonlinearity vs. Temperature Total Error at I PR(max) vs. Temperature. Nonlinearity (%) Total Error (%) Sigma Average - Sigma 7

18 xllctr-ab Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature V (mv) IOUT(Q) Offset Voltage (mv) Sensitivity vs. Temperature Sensitivity Error vs. Temperature Sensitivity (mv/a) Sensitivity Error (%) Nonlinearity vs. Temperature Total Error at I PR(max) vs. Temperature. Nonlinearity (%) Total Error (%) Sigma Average - Sigma 8

19 xllctr-au Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature V (mv) IOUT(Q) Offset Voltage (mv) Sensitivity vs. Temperature Sensitivity Error vs. Temperature 8 Sensitivity (mv/a) 6 8 Sensitivity Error (%) Nonlinearity vs. Temperature Total Error at I PR(max) vs. Temperature. Nonlinearity (%) Total Error (%) Sigma Average - Sigma 9

20 xllctr-ab Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature V (mv) IOUT(Q) Offset Voltage (mv) Sensitivity vs. Temperature Sensitivity Error vs. Temperature 69 Sensitivity (mv/a) Sensitivity Error (%) Nonlinearity vs. Temperature Total Error at I PR(max) vs. Temperature..8 Nonlinearity (%) Total Error (%) Sigma Average - Sigma

21 CHARACTERISTIC PERFORMANCE xllctr-5ab Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature V IOUT(Q) (mv) Temperature ( C) Offset Voltage (mv) Temperature ( C) Sensitivity vs. Temperature 6. Sensitivity Error vs. Temperature Sensitivity (mv/a) Temperature ( C).5 Nonlinearity vs. Temperature Sensitivity Error (%) Temperature ( C) Total Error at I PR(max) vs. Temperature Nonlinearity (%) Temperature ( C) Total Error (%) Temperature ( C) + Sigma Average - Sigma

22 APPLICATION INFORMATION Estimating Total Error vs. Sensed Current The Performance Characteristics tables give distribution (± sigma) values for Total Error at I PR(max) ; however, one often wants to know what error to expect at a particular current. This can be estimated by using the distribution data for the components of Total Error, Sensitivity Error, and Offset Voltage. The ± sigma value for Total Error (E TOT ) as a function of the sensed current (I P ) is estimated as: ( ) V OE E TOT (I) P = E SENS + Sens I P Here, E SENS and V OE are the ± sigma values for those error terms. If there is an average sensitivity error or average offset voltage, then the average Total Error is estimated as: V OE AVG E TOT (I) P = E SENS + AVG AVG Sens I P The resulting total error will be a sum of E TOT and E TOT_AVG. Using these equations and the sigma distributions for Sensitivity Error and Offset Voltage, the Total Error versus sensed current (I P ) is below for the ACS7LLCTR-AB. As expected, as one goes towards zero current, the error in percent goes towards infinity due to division by zero. Total Error (% of Current Measured) Current (A) -ºC + σ -ºC σ 5ºC + σ 5ºC σ 85ºC + σ 85ºC σ Figure : Predicted Total Error as a Function of the Sensed Current for the ACS7LLCTR-AB

23 DEFINITIONS OF ACCURACY CHARACTERISTICS Sensitivity (Sens). The change in sensor IC output in response to a A change through the primary conductor. The sensitivity is the product of the magnetic circuit sensitivity (G/ A) ( G =. mt) 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 full-scale current of the device. Nonlinearity (E LIN ). The nonlinearity is a measure of how linear the output of the sensor IC is over the full current measurement range. The nonlinearity is calculated as: E LIN = V (I ) V IOUT PR(max) IOUT(Q) V (I /) V IOUT PR(max) IOUT(Q) (%) where V IOUT (I PR (max)) is the output of the sensor IC with the maximum measurement current flowing through it and V IOUT (I PR (max)/) is the output of the sensor IC with half of the maximum measurement current flowing through it. Zero-Current Output Voltage (V IOUT(Q) ). The output of the sensor when the primary current is zero. For a unipolar supply voltage, it nominally remains at.5 V CC for a bidirectional device and. V CC for a unidirectional device. For example, in the case of a bidirectional output device, V CC = 5 V translates into V IOUT(Q) =.5 V. Variation in V IOUT(Q) can be attributed to the resolution of the Allegro linear IC quiescent voltage trim and thermal drift. Offset Voltage (V OE ). The deviation of the device output from its ideal quiescent value of.5 V CC (bidirectional) or. V CC (unidirectional) due to nonmagnetic causes. To convert this voltage to amperes, divide by the device sensitivity, Sens. Total Output Error (E TOT ). The difference between the current measurement from the sensor IC and the actual current (I P ), relative to the actual current. This is equivalent to the difference between the ideal output voltage and the actual output voltage, divided by the ideal sensitivity, relative to the current flowing through the primary conduction path: E TOT (I) P = V IOUT_ideal(I P) V IOUT(I P) Sens (I ) I ideal P P (%) The Total Output Error incorporates all sources of error and is a function of I P. At relatively high currents, E TOT will be mostly due to sensitivity error, and at relatively low currents, E TOT will be mostly due to Offset Voltage (V OE ). In fact, at I P =, E TOT approaches infinity due to the offset. This is illustrated in Figures and. Figure shows a distribution of output voltages versus I P at 5 C and across temperature. Figure shows the corresponding E TOT versus I P. I P (A) I P I PR (min) Accuracy Across Temperature Accuracy at 5 C Only Accuracy at 5 C Only Accuracy Across Temperature Increasing V IOUT (V) A Decreasing V IOUT (V) Accuracy Across Temperature Accuracy at 5 C Only Ideal V IOUT Figure : Output Voltage versus Sensed Current E TOT +E TOT V IOUT(Q) Full Scale I P I PR (max) +I P (A) Across Temperature 5 C Only Figure : Total Output Error versus Sensed Current +I P

24 Sensitivity Ratiometry Coefficient (SENS_RAT_COEF). The coefficient defining how the sensitivity scales with V CC. The ideal coefficient is, meaning the sensitivity scales proportionally with V CC. A % increase in V CC results in a % increase in sensitivity. A coefficient of. means that the sensitivity increases by % more than the ideal proportionality case. This means that a % increase in V CC results in an % increase in sensitivity. This relationship is described by the following equation: Sens(V ) = Sens(5 V) CC + (V 5 V) SENS_RAT_COEF CC 5 V This can be rearranged to define the sensitivity ratiometry coefficient as: SENS_RAT_COEF = Sens(V ) CC 5 V Sens(5 V) (V CC 5 V) Zero-Current Output Ratiometry Coefficient (QVO_RAT_ COEF). The coefficient defining how the zero-current output voltage scales with V CC. The ideal coefficient is, meaning the output voltage scales proportionally with V CC, always being equal to V CC /. A coefficient of. means that the zero-current output voltage increases by % more than the ideal proportionality case. This means that a % increase in V CC results in an % increase in the zero-current output voltage. This relationship is described by the following equation: VIOUTQ(V ) = VIOUTQ(5 V) CC + (V 5 V) QVO_RAT_COEF CC 5 V This can be rearranged to define the zero-current output ratiometry coefficient as: QVO_RAT_COEF = VIOUTQ(V ) CC 5 V VIOUTQ(5 V) (V CC 5 V)

25 DEFINITIONS OF DYNAMIC RESPONSE CHARACTERISTICS Power-On Time (t PO ). When the supply is ramped to its operating 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 ±% 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. V V CC (typ.) 9% V IOUT V CC (min.) V CC V IOUT t t t PO t = time at which power supply reaches minimum specified operating voltage t = time at which output voltage settles within ±% of its steady state value under an applied magnetic field Figure : Power-On Time (t PO ) t Rise Time (t r ). The time interval between a) when the sensor IC reaches % of its full-scale value, and b) when it reaches 9% of its full-scale value. The rise time to a step response is used to derive the bandwidth of the current sensor IC, in which ƒ( db) =.5 / t r. Both t r and t RESPONSE are detrimentally affected by eddy-current losses observed in the conductive IC ground plane. Propagation Delay (t pd ). The propagation delay is measured as the time interval a) when the primary current signal reaches % of its final value, and b) when the device reaches % of its output corresponding to the applied current. (%) 9 Primary Current V IOUT Rise Time, tr Propagation Delay, tpd Figure : Rise Time (t r ) and Propagation Delay (t pd ) t Response Time (t RESPONSE ). The time interval between a) when the primary current signal reaches 9% of its final value, and b) when the device reaches 9% of its output corresponding to the applied current. (%) 9 Primary Current V IOUT Response Time, tresponse Figure 5: Response Time (t RESPONSE ) t 5

26 PACKAGE OUTLING DRAWING For Reference Only Not for Tooling Use (Reference MS-AA) Dimensions in millimeters NOT TO SCALE Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown.9 ± A.9 ±. 6. ± REF C PCB Layout Reference View.5 BSC 8X. C Branded Face.75 MAX SEATING PLANE C SEATING PLANE GAUGE PLANE NNNNNNN PPT-AAA LLLLL BSC A B C Terminal # mark area Branding scale and appearance at supplier discretion Reference land pattern layout (reference IPC75 SOIC7P6X75-8M); all pads a minimum of. mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances. B Standard Branding Reference View N = Device part number P= Package Designator T= Device temperature range A=Amperage L= Lot number Belly Brand = Country of Origin Figure 6: Package LC, 8-pin SOICN 6

27 Revision History Number Descriptioon Pages Responsible Date Added Characteristic Performance graphs and Application Information to Preliminary draft to create Final draft All A. Latham January 6, 5 Corrected Features and Benefits A. Latham June 9, 5 Added ACS7LLCTR-5AB-T variant with electrical characteristics, 9 A. Latham June, 5 Corrected Characteristic Performance graph legends; updated Lifetime Drift Characteristics and added Error Over Lifetime electrical characteristics 6-8 A. Latham, S. Milano August, 5 Added ACS7LLCTR-5AB-T variant with electrical characteristics, 6 W. Bussing August 8, 6 5 Added AEC-Q qualified status W. Bussing June 8, 7 6 Added ACS7LLCTR-5AB-T and ACS7LLCTR-5AB-T Characteristic Performance graphs, W. Bussing August, 7 7 Updated Clearance and Creepage rating values W. Bussing January, 8 8 Added Dielectric Surge Strength Test Voltage characteristic Added Common Mode Field Rejection Ratio characteristic 5 W. Bussing January, 8 Copyright 8, reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, 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 any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro s product can reasonably be expected to cause bodily harm. The information included herein is believed to be accurate and reliable. However, assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. For the latest version of this document, visit our website: 7