ACS706ELC-20A

ACS706ELC-20A Bidirectional 1.5 mΩ Hall Effect Based Linear Current Sensor with Voltage Isolation and 20 A Dynamic Range Not for New Design These parts are in production but have been determined to be NOT FOR NEW DESIGN. This classification indicates that sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available. Date of status change: December 26, 2006 Recommended Substitutions: For existing customer transition, and for new customers or new applications, refer to the ACS712. NOTE: For detailed information on purchasing options, contact your local Allegro field applications engineer or sales representative. Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. ACS706ELC-20A Bidirectional 1.5 mΩ Hall Effect Based Linear Current Sensor with Voltage Isolation and 20 A Dynamic Range The Allegro ACS706 family of current sensors provides economical and precise solutions for 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, switched-mode power supplies, and overcurrent fault protection. Pin 8: VCC Pin 7: VOUT Pin 1: IP+ Pin 2: IP+ Pin 3: IP– Pin 4: IP– Pin 6: N.C. Pin 5: GND Package LC Pins 6 and 7 are internally connected in shipping product. For compatibility with future devices, leave pin 6 floating. The device consists of a precision, 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. 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 pins 1 and 2, to pins 3 and 4), which is the path used for current sensing. The internal resistance of this conductive path is typically 1.5 mΩ, providing low power loss. The thickness of the copper conductor allows survival of the device at up to 3× overcurrent conditions. The terminals of the conductive path are electrically isolated from the sensor leads (pins 5 through 8). This allows the ACS706 family of sensors to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques. The ACS706 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 flip-chip uses high-temperature Pb-based solder balls, currently exempt from RoHS. The device is fully calibrated prior to shipment from the factory. Nominal Operating Temperature, TA Range E............................................ –40 to 85ºC Overcurrent Transient Tolerance*, IP ................ 60 A *100 total pulses, 250 ms duration each, applied at a rate of 1 pulse every 100 seconds. ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC .......................................... 16 V Reverse Supply Voltage, VRCC ........................ –16 V Output Voltage, VOUT ........................................ 16 V Reverse Output Voltage, VROUT...................... –0.1 V Output Current Source, IOUT(Source) ................. 3 mA Output Current Sink, IOUT(Sink) ....................... 10 mA Maximum Transient Sensed Current*, IR(max) ... 100 A Operating Temperature, Maximum Junction, TJ(max)....................... 165°C Storage Temperature, TS ...................... –65 to 170°C *Junction Features and Benefits • Small footprint, low-profile SOIC8 package • • • • • • • • • • • 1.5 mΩ internal conductor resistance Excellent replacement for sense resistors 1600 VRMS minimum isolation voltage between pins 1-4 and 5-8 4.5 to 5.5 V, single supply operation 50 kHz bandwidth 100 mV/A output sensitivity and 20 A dynamic range Output voltage proportional to ac and dc currents Factory-trimmed for accuracy Extremely stable output offset voltage Near-zero magnetic hysteresis Ratiometric output from supply voltage Temperature, TJ < TJ(max). TÜV America Certificate Number: U8V 04 12 54214 005 Use the following complete part number when ordering: Part Number ACS706ELC-20A Package SOIC8 surface mount ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Functional Block Diagram +5 V Pin 3 Pin 4 IP– IP– VCC Pin 8 Voltage Regulator To all subcircuits Dynamic Offset Cancellation Amp Filter VOUT Pin 7 Out N.C. Pin 6 A 0.1 μF Gain Temperature Coefficient Offset Trim Control IP+ IP+ Pin 1 Pin 2 GND Pin 5 A Pins 6 and 7 are internally connected in shipping product. For compatibility with future devices, leave pin 6 floating. 2 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A OPERATING CHARACTERISTICS Characteristic Optimized Accuracy Range Linear Sensing Range Supply Voltage Supply Current Output Resistance Output Capacitance Load Output Resistive Load Primary Conductor Resistance RMS Isolation Voltage DC Isolation Voltage Propagation Time Response Time Rise Time Frequency Bandwidth Sensitivity Noise Linearity Symmetry Zero Current Output Voltage Electrical Offset Voltage Magnetic Offset Error Total Output Error1 Symbol IP IR VCC ICC ROUT CLOAD RLOAD RPRIMARY VISORMS VISODC tPROP tRESPONSE tr f Sens VNOISE ELIN ESYM VOUT(Q) VOE IERROM ETOT IP = ±20 A, TA = 25°C IP = ±20 A, TA = 25°C IP = ±20 A, TA = 25°C –3 dB, TA = 25°C; IP is 10 A peak-to-peak; no external filter Over full range of IP , IP applied for 5 ms; TA = 25°C Over full range of IP , IP applied for 5 ms Peak-to-peak, TA = 25°C, no external filter Root Mean Square, TA = 25°C, no external filter Over full range of IP , IP applied for 5 ms Over full range of IP , IP applied for 5 ms IP = 0 A, TA = 25°C IP = 0 A, TA = 25°C IP = 0 A IP = 0 A, after excursion of 20 A IP = ±20 A , IP applied for 5 ms; TA = 25°C IP = ±20 A , IP applied for 5 ms VCC = 5.0 V, output open IOUT = 1.2 mA VOUT to GND VOUT to GND TA = 25°C Pins 1-4 and 5-8; 60 Hz, 1 minute Test Conditions Min. –20 –20 4.5 5 – – 4.7 – 1600 – – – – – – 94 – – – 98 – –15 –50 – – – Typ. – – 5.0 8 1 – – 1.5 2500 5000 3.15 6 6.56 50 100 – 70 12.5 ±1 100 VCC / 2 – – ±0.01 ±1.5 – Max. 20 20 5.5 10 2 10 – – – – – – – – – 106 – – ±3.5 102 – 15 50 ±0.05 – ±8.4 Units A A V mA Ω nF kΩ mΩ V V μs μs μs kHz mV/A mV/A mV mV % % V mV mV A % % ELECTRICAL CHARACTERISTICS, over operating ambient temperature range unless otherwise specified PERFORMANCE CHARACTERISTICS, over operating ambient temperature range unless otherwise specified THERMAL CHARACTERISTICS2,3, TA = –40°C to 125°C, VCC = 5 V unless otherwise specified – Junction-to-Lead Thermal Resistance Junction-to-Ambient Thermal Resistance 1Percentage 2 The Allegro Value 5 – – Units °C/W RθJL Mounted on the Allegro ASEK 70x evaluation board; additional information about reference boards and tests is available on the Allegro Web site Mounted on the Allegro ASEK 70x evaluation board; additional information about reference boards and tests is available on the Allegro Web site – RθJA – 41 – °C/W of IP, with IP = 20 A. Output filtered. Up to a 2.0% shift in ETOT may be observed at end-of-life for this device. 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 connecting the layers. Performance values include the power consumed by the PWB. Further details on the board are available from the ACS704 Frequently Asked Questions document on our website. Further information about board design and thermal performance also can be found on pages 16 and 17 of this datasheet. 3R θJA values shown in this table are typical values, measured on the Allegro evaluation board. The actual thermal performance depends on the board design, the airflow in the system, and thermal interactions between the sensor and surrounding components through the PCB and the ambient air. To improve thermal performance, see our applications material on the Allegro Web site. 3 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Typical Performance Characteristics Supply Current versus Ambient Temperature VCC = 5 V 10.0 9.5 9.0 ICC (mA) 8.5 8.0 7.5 7.0 6.5 6.0 -50 -25 0 25 50 75 100 125 150 TA (°C) Supply Current versus Applied VCC 8.66 8.64 8.62 8.60 8.58 8.56 8.54 8.52 8.50 8.48 8.46 8.44 4.5 4.6 4.7 4.8 4.9 5 VCC (V) 5.1 5.2 5.3 5.4 5.5 ICC (mA) 4 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Output Voltage versus Primary Current VCC = 5 V 5.0 4.5 4.0 3.5 VOUT (V) 3.0 2.5 2.0 1.5 1.0 0.5 0 –25 –20 –15 –10 –5 0 IP (A) 5 10 15 20 25 °C –40 –20 25 85 150 Sensitivity versus Primary Current VCC = 5 V 110 108 106 104 °C –40 –20 25 85 150 Sens (mV/A) 102 100 98 96 94 92 90 –25 –20 –15 –10 –5 0 IP (A) 5 10 15 20 25 5 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Zero Current Output Voltage vs. Ambient Temperature IP = 0 A 2.525 2.520 2.515 VOUT(Q) (V) 2.510 2.505 2.500 2.495 2.490 2.485 2.480 2.475 -50 -25 0 25 50 75 100 125 150 TA (°C) Zero Current Output Currrent versus Ambient Temperature 0.25 0.20 0.15 (Data in above chart converted to amperes) IP = 0 A IVOUT(Q) (A) 0.10 0.05 0 -0.05 -0.10 -0.15 -0.20 -0.25 -50 -25 0 25 50 75 100 125 150 TA (°C) 6 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Magnetic Offset versus Ambient Temperature VCC = 5 V; IP = 0 A, after excursion to 20 A 0 –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 TA (°C) 75 100 125 150 VOM (mA) Nonlinearity versus Ambient Temperature VCC = 5 V IP = 20 A 1.0 0.8 0.6 0.4 ELIN (%) 0.2 0 –0.2 –0.4 –0.6 –0.8 –1.0 –50 –25 0 25 50 75 100 125 150 TA (°C) 7 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Typical Percentage Error versus Ambient Temperature Measurements at TA = –40, –20, 25, 85, and 125°C 8 6 4 ETOT (% of 20 A) 2 0 –2 –4 –6 –8 –50 Mean + 3 Sigma Mean Mean – 3 Sigma –25 0 25 TA (°C) 50 75 100 125 150 TA (°C) 8 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Step Response of ACS706ELC-20A at TA=25°C ACS706 Output (mV) 5 A Excitation Signal Time = 5 μs/div. Excitation signal = 1.00 A/div. Output = 100 mV/div. Typical Peak-to-Peak Noise of ACS706ELC-20A at TA=25°C Time = 20 μs/div. Noise = 20.0 mV/div. 9 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A ACS706ELC-20A Noise Filtering and Frequency Response Performance Break Frequency of Filter on Output (kHz) Unfiltered 80 50 40 20 10 7.0 3.3 0.6 0.3 Resistance (kΩ) – 0.200 0.320 0.392 0.800 1.6 3.15 4.8 26 53 Capacitance (μF) – Nominal Programmed Sensitivity (mV/A) Filtered Peak-toPeak Noise (mV) 70.0 58.8 49.9 46.3 32.9 Resolution with Filtering (A) 0.700 0.588 0.499 0.463 0.329 0.219 0.133 0.098 0.013 0.00583 Rise Time for 5A Step, Filtered (μs) 6.56 7.82 9.55 10.25 16.15 30.14 53.29 79.73 394.66 724.73 0.01 100 21.9 13.3 9.8 1.3 0.58 10 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Definitions of Accuracy Characteristics Sensitivity (Sens). The change in sensor 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 full-scale current of the device. Noise (VNOISE). 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 (ELIN): The degree to which the voltage output from the sensor varies in direct proportion to the primary current through its full-scale amplitude. Nonlinearity in the output can be attributed to the saturation of the flux concentrator approaching the full-scale current. The following equation is used to derive the linearity: 100 1– {[ 100 (Vout_full-scale amperes – VOUT(Q) ) 2 (Vout_half-scale amperes – VOUT(Q) ) [{ where Vout_full-scale amperes = the output voltage (V) when the sensed current approximates full-scale ±IP . Symmetry (ESYM). The degree to which the absolute voltage output from the sensor varies in proportion to either a positive or negative full-scale primary current. The following formula is used to derive symmetry: Vout_+full-scale amperes – VOUT(Q) VOUT(Q) – Vout_–full-scale amperes Quiescent output voltage (VOUT(Q)). The output of the sensor when the primary current is zero. For a unipolar supply voltage, it nominally remains at VCC ⁄ 2. Thus, VCC = 5 V translates into VOUT(Q) = 2.5 V. Variation in VOUT(Q) can be attributed to the resolution of the Allegro linear IC quiescent voltage trim and thermal drift. Electrical offset voltage (VOE). The deviation of the device output 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 (ETOT). The accuracy represents the maximum deviation of the actual output from its ideal value. This is also known as the total ouput error. The accuracy is illustrated graphically in the Output Voltage versus Current chart on the following page. Accuracy is divided into four areas: • 0 A at 25°C. Accuracy of sensing zero current flow at 25°C, without the effects of temperature. • 0 A over Δ temperature. Accuracy of sensing zero current flow including temperature effects. • Full-scale current at 25°C. Accuracy of sensing the full-scale current at 25°C, without the effects of temperature. • Full-scale current over Δ temperature. Accuracy of sensing full-scale current flow including temperature effects. Ratiometry. The ratiometric feature means that its 0 A output, VOUT(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, ΔVOUT(Q)RAT (%): 100 VOUT(Q)VCC / VOUT(Q)5V The ratiometric change in sensitivity, ΔSensRAT (%), is defined as: 100 SensVCC / Sens5V ‰ VCC / 5 V  ‰ VCC / 5 V  11 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Output voltage vs. current, illustrating sensor accuracy at 0 A and at full-scale current Increasing VOUT (V) Accuracy Over ΔTemperature Accuracy 25°C Only Average VOUT Accuracy Over ΔTemperature Accuracy 25°C Only –IP (A) –IP IP +IP (A) Full Scale 0A Accuracy 25°C Only Accuracy Over ΔTemperature Decreasing VOUT (V) 12 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Definitions of Dynamic Response Characteristics Propagation delay (tPROP): The time required for the sensor output to reflect a change in the primary current signal. Propagation delay is attributed to inductive loading within the linear IC package, as well as in the inductive loop formed by the primary conductor geometry. Propagation delay can be considered as a fixed time offset and may be compensated. I (%) 90 Primary Current Transducer Output 0 Propagation Time, tPROP t Response time (tRESPONSE): The time interval between a) when the primary current signal reaches 90% of its final value, and b) when the sensor reaches 90% of its output corresponding to the applied current. I (%) 90 Primary Current Transducer Output 0 Response Time, tRESPONSE t Rise time (tr): The time interval between a) when the sensor 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 current sensor, in which ƒ(–3 dB) = 0.35 / tr. Both tr and tRESPONSE are detrimentally affected by eddy current losses observed in the conductive IC ground plane. I (%) 90 Primary Current Transducer Output 10 0 Rise Time, tr t 13 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Standards and Physical Specifications Parameter Flammability (package molding compound) Fire and Electric Shock Specification UL recognized to UL 94V-0 UL60950-1:2003 EN60950-1:2001 CAN/CSA C22.2 No. 60950-1:2003 Device Branding Key (Two alternative styles are used) ACS 704 T ACS706T ELC20A YYWWA E LC 20A YY WW A ACS 704 T ACS706T ELC20A L...L YYWW E LC 20A L...L YY WW Allegro Current Sensor Device family number Indicator of 100% matte tin leadframe plating Operating ambient temperature range code Package type designator Primary sensed current Manufacturing date code: Calendar year (last two digits) Manufacturing date code: Calendar week Manufacturing date code: Shift code Allegro Current Sensor Device family number Indicator of 100% matte tin leadframe plating Operating ambient temperature range code Package type designator Primary sensed current Manufacturing lot code Manufacturing date code: Calendar year (last two digits) Manufacturing date code: Calendar week 14 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Chopper Stabilization Technique Chopper Stabilization is an innovative circuit technique that is used to minimize the offset voltage of a Hall element and an associated on-chip amplifier. Allegro patented a Chopper Stabilization 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 suppressed 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 Voltage, 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. Regulator Clock/Logic Hall Element Amp Low-Pass Filter Concept of Chopper Stabilization Technique Sample and Hold 15 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Applications Information Transient Common-Mode Voltage Rejection in the ACS706 In order to quantify transient common-mode voltage rejection for the ACS706, a device was soldered onto a printed circuit board. A 0.1 μF bypass capacitor and a 5 V dc power supply were connected between VCC and GND (pins 8 and 5) for this device. A 10 kΩ load resistor and a 0.01 μF capacitor were connected in parallel between the VOUT pin and the GND pin of the device (pins 7 and 5). 1 2 3 V1 VOUT=0V VOUT=20VPP freq=variable 8 7 I P 6 5 Output C3 C=0.01µF C0 C=0.1µF Vcc V0 VDC=5V 4 R=10kΩ R0 Ground GND ACS706 Schematic Diagram of the Circuit used to Measure Transient Rejection A function generator was connected between the primary current conductor (pins 1 thru 4) and the GND pin of the device (pin 5). This function generator was configured to generate a 10 V peak (20 V peak-to-peak) sine wave between pins 1-4 and pin 5. Note that the sinusoidal stimulus was applied such that no electrical current would flow through the copper conductor composed of pins 1-4 of this device. The frequency of this sine wave was varied from 60 Hz to 5 MHz in discrete steps. At each frequency, the statistics feature of an oscilloscope was used to measure the voltage variations (noise) on the ACS706 output in mV (peak to peak). The noise was measured both before and after the application of the stimulus. Transient common-mode voltage rejection as a function of frequency is shown in the following figure. –30 Transient Rejection (dB) –35 –40 –45 –50 –55 –60 0.06 1 10 100 300 600 800 1000 3000 5000 Frequency of 20 V Peak-to-Peak Stimulus (kHz) 16 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A The Effect of PCB Layout on ACS706 Thermal Performance Eight different PC boards were fabricated to characterize the effect of PCB design on the operating junction temperature of the Hall-effect IC inside of the ACS706. These PC boards are shown in the figure below. 2 oz. Cu on one side of board 2 oz. Cu on both sides of board An ACS706 device was soldered on to each PCB for thermal testing. The results of the testing are shown in the following table. Test Results on Eight Thermal Characterization PCBs by 14 gauge wires Tested at 15A, TA = 20°C, still air, 2 oz. copper traces, current carried on and off board PC Boards Sides with Traces Trace Width (mm) 4 1 1.5 4 1.5 4 2 1.5 4 1.5 Trace Length (mm) 50 50 10 10 50 50 10 10 Temperature Rise Above Ambient (°C) 90 Overheated 48 110 53 106 38 54 17 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Improved PC Board Designs The eight PC boards in the figure above do not represent an ideal PC board for use with the ACS706. The ACS706 evaluation boards, for sale at the Allegro Web site On-Line Store, represent a more optimal PC board design (see photo below). On the evaluation boards, the current to be sensed flows through very wide traces that were fabricated using 2 layers of 2 oz. copper. Thermal management tests were conducted on the Allegro evaluation boards and all tests were performed using the same test conditions described in the bulleted list above. The results for these thermal tests are shown in the table below. When using the Allegro evaluation boards we see that even at an applied current of 20 A the junction temperature of the ACS706 is only ≈30 degrees above ambient temperature. Test Results on Eight Electrical Characterization PCBs Tested at TA = 20°C, still air Applied Current (A) 15 20 Temp Rise Above Ambient (°C) 22 31 Allegro Current sensor evaluatin board with ACS706 and external connections. 18 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com ACS706ELC-20A Package LC, 8-pin SOIC 6.20 .244 5.80 .228 0.25 [.010] M B M 5.00 .197 4.80 .189 8 A B 8º 0º 0.25 .010 0.17 .007 Preliminary dimensions, for reference only Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only (reference JEDEC MS-012 AA) Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Terminal #1 mark area A 4.00 .157 3.80 .150 1.27 .050 0.40 .016 1 2 0.25 .010 8X 0.10 [.004] C 8X 0.51 .020 0.31 .012 0.25 [.010] M C A B 1.27 .050 SEATING PLANE 1.75 .069 1.35 .053 0.25 .010 0.10 .004 C SEATING PLANE GAUGE PLANE The products described herein are manufactured under one or more of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283; 5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719; 5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents pending. Allegro MicroSystems, Inc. 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 products are not authorized for use as critical components in life-support devices or systems without express written approval. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. Copyright©2005, Allegro MicroSystems, Inc. 19 ACS706ELC20A-DS, Rev. 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com