ACS726 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain FEATURES AND BENEFITS • Fully differential architecture for improved immunity to offset drift and common mode noise • Spare differential back end amplifier for externally adjustable gain and bandwidth using simple RC networks • Greatly improved bandwidth through proprietary amplifier and filter design techniques • High bandwidth 120 kHz analog output • Patented integrated digital temperature compensation circuitry allows nearly closed-loop accuracy, through entire temperature range, in an open loop sensor • 1.1 mΩ primary conductor resistance for low power loss and high inrush current withstanding capability • Small footprint, low-profile QSOP24 package suitable for space-constrained applications • Integrated shield virtually eliminates capacitive coupling from current conductor to die due to high dV/dt voltage transients Continued on the next page… Package: 24-pin QSOP (suffix LF) DESCRIPTION The Allegro™ ACS726 current sensor IC family provides economical and precise solutions for AC 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, switched-mode power supplies, and overcurrent fault protection. The fully differential output gives superior immunity to output offset drift as well common mode noise. ACS726 is the first current sensor IC to include a fully differential back-end amplifier (BEA) that can be used to adjust gain and bandwidth via external RC networks. The BEA is fully independent and when unused, it can be powered down to reduce power consumption. 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. Device accuracy is optimized through the close proximity of the magnetic field to the Hall transducer. A Continued on the next page… Approximate scale 1 2 3 4 5 6 IP+ IP+ IP+ IP+ IP+ IP+ NC NC VCC VOUTGP VOUTGN ACS726 19 VINGN 18 VINGP IP 7 8 9 10 11 12 IP– IP– IP– IP– IP– IP– VOUTP VOUTN GND NC NC 3.3 V 24 23 22 21 20 CBYPASS 0.1 µF RFB1 RFB2 RIN1 RIN2 17 16 15 14 13 Typical Application Current sensor IC gain can be set using RFB and RIN ACS726-DS, Rev. 1 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain ACS726 Features and Benefits (continued) • 3 to 3.6 V, single supply operation • Factory-trimmed sensitivity and quiescent output voltage for improved accuracy • Chopper stabilization results in extremely stable quiescent output voltage • Ratiometric output from supply voltage Description (continued) precise, proportional voltage is provided by the low-offset, chopperstabilized BiCMOS Hall IC, which is programmed for accuracy after packaging. The output of the device has a positive differential voltage ( VOUTP – VOUTN ) when an increasing current flows through the primary copper conduction path (from pins 1 through 6, to pins 7 through 12), which is the path used for current sensing. The internal resistance of this conductive path is 1.1 mΩ typical, providing low power loss. The terminals of the conductive path are electrically isolated from the sensor IC signal leads (pins 13 through 24). This allows the ACS726 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. The ACS726 is provided in a small, low-profile surface mount QSOP24 package (suffix LF). 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, excluding the BAE, is fully calibrated prior to shipment from the factory. Selection Guide Part Number Optimized Range for Sensed Current, IP (A) Linear Range for Sensed Current, IP (A) Sensitivity, Sens (Typ) (mV/A)1 ACS726LLFTR-20B-T3 ±20 ±20 100 ACS726LLFTR-40B-T3 ±40 ±40 50 1Measured differently when V CC Operating Ambient Temperature Range TA, (°C) Packing2 –40 to 150 Tape and reel, 2500 pieces per 13-in. reel = 3.3 V and using a 2000 mV dynamic range. 2Contact Allegro™ for additional packing options. 3 Variant not intended for automotive applications. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 ACS726 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain Absolute Maximum Ratings Characteristic Supply Voltage Reverse Supply Voltage Symbol Rating Unit VCC VCC pin Notes 6 V VRCC VCC pin –0.1 V VOUTP , VOUTN VOUTP and VOUTN pins 6 V VROUTP, VROUTN VOUTP and VOUTN pins –0.1 V VINGP, VINGIN VINGP and VINGIN pins 6 V BEA Reverse Input Voltage VRINGP , VRINGN VINGP and VINGN pins –0.1 V BEA Output Voltage VOUTGP , VOUTGN VOUTGP and VOUTGN pins 6 V BEA Reverse Output Voltage VROUTGP , VROUTGN VOUTGP and VOUTGN pins –0.1 V VOUTP, VOUTN, VOUTGP, VOUTGN pins to GND 3 mA VCC pin to VOUTP, VOUTN, VOUTGP, VOUTGN 10 mA 2100 VAC 277 VAC 391 Vpk or VDC Output Voltage Reverse Output Voltage BEA Input Voltage Output Source Current Output Sink Current Electric Strength Test Voltage Working Voltage IOUT(SOURCE) IOUT(SINK) VESTV Vworking Between pins 1-12 and 13-24; 60 Hz, 1 minute (Agency Type Test), TA = 25°C For single protection according to UL 1577 standard; for higher continuous voltage ratings, please contact Allegro Operating Ambient Temperature TA –40 to 150 ºC Maximum Junction Temperature TJ(max) 165 ºC Tstg –65 to 170 ºC Storage Temperature Range L Thermal Characteristics may require derating at maximum conditions, see application information Characteristic Package Thermal Resistance (Junction to Ambient) Symbol RθJA Test Conditions* On Allegro ACS726 evaluation board (expected value) Value Unit 27 ºC/W *Additional thermal information available on the Allegro website. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain ACS726 Pin-out Diagram and Terminal List Table IP+ 1 24 NC IP+ 2 23 NC IP+ 3 22 VCC IP+ 4 IP+ 5 IP+ 6 19 VINGN IP– 7 18 VINGP IP– 8 Terminal List Table Number Name Function 21 VOUTGP 1 through 6 IP+ Terminals for current being sensed; fused internally 20 VOUTGN 7 through 12 IP– Terminals for current being sensed; fused internally 15 GND Signal ground terminal 17 VOUTP 16 VOUTN Negative analog output IP– 9 16 VOUTN 17 VOUTP Positive analog output IP– 10 15 GND IP– 11 14 NC 18 VINGP Gain stage positive analog input IP– 12 13 NC 19 VINGN Gain stage negative analog input 20 VOUTGN Gain stage negative analog output 21 VOUTGP Gain stage positive analog output 22 VCC 13,14,23,24 NC Package LF, 24-Pin QSOP Pin-out Diagram Device power supply terminal No Connection; connect to GND for optimal ESD performance VCC IP+ VOUTN VOUTP Hall Current Drive Temperature Sensor EEPROM and Control Logic IP− Dynamic Offset Cancellation Sensitivity Control IP+ VINGP VINGN Offset Control VOUTGP Signal Recovery VOUTGN Back End Amplifier (BEA) Stage IP− GND Functional Block Diagram Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4 ACS726 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain COMMON OPERATING CHARACTERISTICS: not including BEA, TA= –40°C to 150°C, VCC = 3.3 V, CBYPASS = 0.1 μF; unless otherwise specified Characteristic Supply Voltage Supply Output Impedance Supply Current Output Capacitive Load Output Resistive Load Primary Conductor Resistance Rise Time1 Propagation Delay1 Response Time1 Internal Bandwidth1 Linearity Error1 Saturation Voltage Power-On Time1 Differential Quiescent Output Voltage Symbol Test Conditions VCC VCCIMP Min. Typ. Max. Unit 3 3.3 3.6 V – – 5 Ω VCC = 3.3 V, no output load, BEA disabled 8 14 23 mA ICCTOTAL VCC = 3.0 V to 3.6 V, BEA Enabled 12 22 40 mA CL VOUTP to GND, VOUTN to GND – – 4.7 nF RL VOUTP to GND, VOUTN to GND ICC 4.7 – – kΩ TA = 25°C – 1.1 – mΩ tr IP = IP(MAX); TA = 25°C, CL = 1 nF – 3.7 – μs tpd IP = IP(MAX); TA = 25°C, CL = 1 nF – 2.5 – μs IP = IP(MAX); TA = 25°C, CL = 1 nF, 90% input to 90% VIOUTdiff – 5 – μs Small signal –3 dB; TA = 25°C, CL = 1 nF – 120 – kHz Rprimary tRESPONSE BWi -1 < 0.5 1 % VSAT(H) ErrLIN TA = 25°C, RL = 4.7 kΩ to GND VCC – 0.3 – – V VSAT(L) TA = 25°C, RL = 4.7 kΩ to VCC – – 0.3 V TA = 25°C, IP = IP(MAX) – 85 – µs tPO – 0 – V Common Mode Output Voltage1 VCMO IP = 0, no load, VCC = 3.3 V, TA = 25°C to 150°C 1.4 1.65 1.9 V Common Mode Offset Voltage VCMOE IP = 0, no load, VCC = 3.3 V, TA = 25°C to 150°C -250 20 250 mV Common Mode Output Voltage Ratiometry1 ∆VCMORAT TA = 25C, VCC = 3.3 V +/-10% – 100 – % Sensitivity Ratiometry1 ∆SensRAT TA = 25C, VCC = 3.3 V +/-10% – 100 – % 1See VIOUTdiff(Q) Across full range of IP IP = 0 Characteristic Definitions section. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 ACS726 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain ACS726-20B OPERATING CHARACTERISTICS: not including BEA, TA= –40°C to 150°C, VCC = 3.3 V, CBYPASS = 0.1 μF; unless otherwise specified Characteristic Current Sensing Range Differential Sensitivity1 Sensitivity Drift Over Lifetime2 Noise Input-Referenced Noise Density Zero Current Output Voltage Differential Offset Voltage3 Symbol Test Conditions Min. Typ. Max. Unit –20 – 20 A Across full range of IP , TA = 25°C 98 100 102 mV/A Across full range of IP , TA = –40°C to 25°C, not cold trimmed – 100 – mV/A Across full range of IP , TA = 25°C to 150°C 97 100 103 mV/A TA = -40C to 150C, shift after qualification testing – ±1 – % – 10.5 – mVRMS – 305 – µA / √Hz IP = 0 A, TA = 25°C, VCC = 3.3 V 1.4 1.65 1.9 V TA = 25°C -15 ±5 15 mV – ±10 – mV IP Sensdiff ∆SensLIFE VNOISE(RMS) BWi = 120 kHz, TA = 25°C, CL= 1 nF to GND IND(RMS) VOUTP(Q) , VOUTN(Q) VOE BWi ≤ 120 kHz, TA = 25°C, CL= 1 nF to GND TA = –40°C to 25°C, not cold trimmed TA = 25°C to 150°C Offset Voltage Drift Over Lifetime2 Total Output Error 4,5 Total Output Error Drift Over Lifetime2 ∆VOELIFE ErrTOT ∆ErrTOTLIFE -15 ±5 15 mV TA = -40C to 150C, shift after qualification testing – ±2 – mV IP = ±20 A, TA = 25°C, BWi = 120 kHz -3 ±1 3 % IP = ±20 A, TA = –40°C to 25°C, BWi = 120 kHz, not cold trimmed – ±2 – % IP = ±20 A, TA = 25°C to 150°C, BWi = 120 kHz -3 ±1 3 % TA = -40C to 150C, shift after qualification testing – ±1 – % 1This parameter may drift a maximum of ∆SensLIFE over lifetime. on characterization data obtained during standardized stress test for Qualification of Integrated Circuits. Cannot be guaranteed. Drift is a function of customer application conditions. Please contact Allegro MicroSystems for further information. 3This parameter may drift a maximum of ∆V OELIFE over lifetime. 4This parameter may drift a maximum of ∆Err TOTLIFE over lifetime. 5Measured as a percentage of a 2000 mV dynamic range. 2Based Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 ACS726 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain ACS726-40B OPERATING CHARACTERISTICS: not including BEA, TA= –40°C to 150°C, VCC = 3.3 V, CBYPASS = 0.1 μF; unless otherwise specified Characteristic Current Sensing Range Differential Sensitivity1 Symbol Test Conditions Min. Typ. Max. Unit –40 – 40 A Across full range of IP , TA = 25°C 49 50 51 mV/A Across full range of IP , TA = –40°C to 25°C, not cold trimmed – 50 – mV/A 48.5 50 51.5 mV/A – ±1 – % – 5.25 – mVRMS – 305 – µA / √Hz IP = 0 A, TA = 25°C, VCC = 3.3V 1.40 1.65 1.9 V TA = 25°C -15 ±3 15 mV – ±8 – mV -15 ±3 15 mV – ±2 – mV IP Sensdiff Across full range of IP , TA = 25°C to 150°C Sensitivity Drift Over Lifetime2 Noise Input-Referenced Noise Density Zero Current Output Voltage Differential Offset Voltage3 ∆SensLIFE TA = -40C to 150C, shift after qualification testing VNOISE(RMS) BWi = 120 kHz, TA = 25°C, CL= 1 nF to GND IND(RMS) VOUTP(Q) , VOUTN(Q) VOE BWi ≤ 120 kHz, TA = 25°C, CL= 1 nF to GND TA = –40°C to 25°C, not cold trimmed TA = 25°C to 150°C Offset Voltage Drift Over Lifetime2 ∆VOELIFE TA = -40C to 150C, shift after qualification testing IP = ±40 A, TA = 25°C, BWi = 120 kHz Total Output Error 4,5 Total Output Error Drift Over Lifetime2 ErrTOT ∆ErrTOTLIFE -2.5 ±1 2.5 % IP = ±40 A, TA = –40°C to 25°C, BWi = 120 kHz, not cold trimmed – ±2 – % IP = ±40 A, TA = 25°C to 150°C, BWi = 120 kHz -2.5 ±1 2.5 % – ±1 – % TA = -40C to 150C, shift after qualification testing 1This parameter may drift a maximum of ∆SensLIFE over lifetime. on characterization data obtained during standardized stress test for Qualification of Integrated Circuits. Cannot be guaranteed. Drift is a function of customer application conditions. Please contact Allegro MicroSystems for further information. 3This parameter may drift a maximum of ∆VOELIFE over lifetime. 4This parameter may drift a maximum of ∆Err TOTLIFE over lifetime. 5Measured as a percentage of a 2000 mV dynamic range. 2Based Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 ACS726 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain Differential Back End Amplifier (BEA) OPERATING CHARACTERISTICS1: TA= –40°C to 150°C, VCC = 3.3 V, CBYPASS = 0.1 μF; unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. Max. Unit Load Output Capacitive Load CL(BEA) VOUTGP to GND, VOUTGN to GND – – 4.7 nF Output Resistive Load RL(BEA) VOUTGP to GND, VOUTGN to GND 4.7 – – kΩ Gain Setting Resistance Feedback Resistor1 RFB(BEA) 9.4 – 50 kΩ Resistor1 RIN(BEA) 4.7 – 25 kΩ GOL(BEA) – 90 – dB Input AC Performance Open Loop Gain Closed Loop Gain2 Bandwidth Gain Bandwidth Product Differential Slew Rate Settling Time to 1% Input-Referred Voltage Noise Density GCL(BEA) BW(BEA) GBWP(BEA) 2 – 10 – GCL(BEA) = 2, CL(BEA) = 1 nF – 1000 – kHz CL(BEA) = 1 nF – 2000 – kHz SRD(BEA) GCL(BEA) = 2, CL(BEA) = 1 nF – 1.5 – V/µs tS(BEA) GCL(BEA) = 2, CL(BEA) = 1 nF, VOUTGP – VOUTGN = 100 mV – 3 – µs TA = 25°C, BW(BEA) < 120 kHz, GCL(BEA) = 2 – 40 – nV/ √Hz At TA = 25°C -7 ±3 7 mV At TA = 25°C to 150°C -7 ±3 7 mV GCL(BEA) = 2, CL(BEA) = 1 nF 3.5 7 17 mA GCL(BEA) = 2, CL(BEA) = 1 nF, BW(BEA) < 1 kHz – -70 – dB VCMIRMIN (BEA) VCC = 3.3 V, GCL(BEA) = 2, RIN(BEA) = 4.7 K, RFB(BEA) = 9.4 K 1 – – V VCMIRMAX VCC = 3.3 V, GCL(BEA) = 2, RIN(BEA) = 4.7 K, RFB(BEA) = 9.4 K – – 2.15 V GCL(BEA) = 2, CL(BEA) = 1 nF, BW(BEA) < 1 kHz – 60 – dB -1.5 <1 1.5 µA VCC – 0.3 – – V VND(BEA) DC Performance Input-Referred Differential Offset Voltage VOEIR(BEA) Quiescent Operating Current3 IQ(BEA) Power Supply Rejection Ratio PSRR(BEA) Input Minimum Common Mode Input Range (BEA) Common Mode Rejection Ratio Input Bias Current CMRR(BEA) Ibias(BEA) VCC = 3.3 V, VINGP = VINGN = 1.65 V Output Saturation Voltage VSAT(H)(BEA) TA = 25°C, RL(BEA) = 4.7 kΩ to GND VSAT(L)(BEA) TA = 25°C, RL(BEA) = 4.7 kΩ to VCC – – 0.3 V Common Mode Output Voltage VCMO(BEA) VCC = 3.3 V, GCL = 2, TA = 25°C to 150°C 1.4 1.65 1.9 V Common Mode Offset Voltage VCMOE(BEA) VCC = 3.3 V, GCL = 2, TA = 25°C to 150°C -250 ±20 250 mV – <1 – Ω – <±0.1 – % DC Output Resistance ROUT(BEA) Linearity ErrLin(BEA) GCL(BEA) = 2, Over 2 V differential dynamic range 1If larger resistor values are used, settling time deteriorates. Adding a capacitor in parallel with the feedback resistor improves settling time. does not guarantee BAE performance and stability for Closed Loop Gain outside the recommended range. 3The Back End Amplifier can be powered-down by connecting VINGP and VINGN to GND, causing VOUTGP and VOUTGN to be = Vcc/2 2Allegro Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 ACS726 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain CHARACTERISTIC PERFORMANCE DATA Data taken using the ACS726LLFTR-20B-T Timing Data Response Time (90%input-90%output) IP=20 A, 10% to 90% IP rise time < 1 µS, CBYPASS = 0.1 µF, CL =1 nF from VOUTP to GND and VOUTN to GND IP=20A 90% of input VOUTP VOUTN tRESPONSE=4.3µS 90% of output VOUTP-VOUTN Rise Time (10%output-90%output) IP=20 A, 10% to 90% IP rise time < 1 µS, CBYPASS = 0.1 µF, CL = 1 nF from VOUTP to GND and VOUTN to GND IP=20A VOUTP VOUTN tr=3.5µS 90% of output VOUTP-VOUTN 10% of output Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9 ACS726 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain Propagation Delay(20%input-20%output) IP = 20 A, 10% to 90% IP rise time < 1 µS, CBYPASS = 0.1 µF, CL = 1 nF from VOUTP to GND and VOUTN to GND IP=20A VOUTP 20% of input VOUTN tpd=2.5µS VOUTP-VOUTN 20% of output Power-On Time IP = 20 A, 10% to 90% rise time < 1 µS VOUTP VOUTN VCC VCC(min)=3V tPO=83µS VOUTP-VOUTN 90% of output Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 10 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain ACS726 CHARACTERISTICS DEFINITIONS Accuracy Characteristics Total Output Error (ETOT)* The maximum deviation of the Differential Sensitivity (Sensdiff) The change in the differential sensor IC output (VOUTP – VOUTN ) in response to a 1 A change through the primary conductor. The sensitivity is the product of the magnetic circuit sensitivity (G / A) (1 G = 0.1 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. Noise (VNOISE(RMS)) The unfiltered output noise of the current sensor IC. Dividing the noise (mV) by the sensitivity (mV/A) provides the smallest current that the device is able to resolve. Linearity Error (ErrLIN)* The ACS726 is designed to provide a linear output in response to a ramping current. Consider two current levels, I1 and I2. Ideally, the sensitivity of a device is the same for both currents, for a given supply voltage and temperature. Nonlinearity is present when there is a difference between the sensitivities measured at I1 and I2. Nonlinearity is calculated separately for the positive (ErrLIN pos) and negative (ErrLINneg) applied currents as follows: {( {( )} )} actual output from its ideal value, also referred to as accuracy, illustrated graphically in the Output voltage versus Sensed current chart . ETOT is divided into four areas: 0 A at 25°C. Accuracy at the zero current flow at 25°C, without 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 full-scale current at 25°C, without the effects of temperature. Full-scale current over Δ temperature. Accuracy at the fullscale current flow including temperature effects. ETOT(IP) = 100(%) X [ ] (VIOUTdiff(Ip) - VIOUTdiff_IDEAL(Ip) ) Sensdiff_IDEAL X IP Where VIOUTdiff_IDEAL(IP) = VIOUTdiff_IDEAL(Q) + (Sensdiff_IDEAL X Ip) where: The Total Output Error incorporates all sources of error and is a function of IP. At relatively high currents, ETOT will be mostly due to sensitivity error, and at relatively low currents, ETOT will be mostly due to Offset Voltage (VOE ). In fact, at IP = 0, ETOT approaches infinity due to the offset. SensIx = (VIOUTdiff(Ix) – VIOUTdiff(Q))/ Ix and IPOSx and INEGx are positive and negative currents. Then: This is illustrated in the total output error versus sensed current chart. ErrLIN = max( ErrLINpos, ErrLINneg ) Ratiometry The ratiometric feature means that the Common Mode ErrLINpos = 100(%) X 1 - SensIPOS2 SensIPOS1 ErrLINneg = 100(%) X 1 - SensINEG2 SensINEG1 Differential Quiescent Output Voltage (VIOUTdiff(Q))* The differential output of the sensor IC when the primary current is zero. It is nominally 0 V. Differential Offset Voltage (VOE) The deviation of the device output, from its ideal quiescent value of 0 V, due to nonmagnetic causes. To convert this voltage to amperes, divide by the device sensitivity, Sens. Common Mode Output Voltage (VCMO ) The average of the positive and negative zero current output voltages: (VOUTP(Q) + VOUTN(Q) ) / 2. VCMO nominally equals VCC / 2. Common Mode Offset Voltage (VCMOE) The deviation of the Output Voltage, VCMO , and Differential Sensitivity, Sensdiff , are proportional to the supply voltage, VCC . The following formula is used to derive the ratiometric change in common mode 0 A output voltage, ΔVCMORAT (%). 100 VCMO(VCC) / VCMO(3.3V) VCC / 3.3 V The ratiometric change in sensitivity, ΔSensRAT (%), is defined as: 100 Sensdiff(VCC) /Sensdiff(3.3V) VCC / 3.3 V Common Mode Output Voltage from its ideal value of VCC / 2. *Definitions of VIOUT: • VIOUTdiff = VOUTP – VOUTN • VIOUTdiff(Q) = VOUTP(Q) – VOUTN(Q) ; sensed current equals 0 A Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 11 ACS726 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain Output Voltage versus Sensed Current Total Output Error at 0 A and at Full-Scale Current ETOT Across full temperature Increasing VIOUTdiff (V) ETOT at 25°C Only Average VIOUT ETOT Across full temperature ETOT at 25°C Only -20 A (20 AB) -40 A (40 AB) VIOUT(Q) –IP (A) +IP (A) Full Scale 20 A (20 AB) 40 A (40 AB) 0A ETOT at 25°C Only Decreasing VIOUTdiff (V) ETOT Across full temperature Total Output Error versus Sensed Current +ETOT Across Temperature 25°C Only –IP +IP –ETOT Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 12 ACS726 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain Dynamic Response Characteristics Power-On Time Power-On Time (tPO ). 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. PowerOn Time, tPO , is defined as the time it takes for the output voltage to settle within ±10% of its steady state value when full scale IP is applied, after the power supply has reached its minimum specified operating voltage, VCC(min), as shown in the chart at right. V VCC VCC(typ.) VIOUTdiff 90% VIOUT VCC(min.) Rise Time (tr ) The time interval between a) when the sensor IC differential output reaches 10% of its full scale value, and b) when it reaches 90% of its full scale value. tPO t1 t2 t1= time at which power supply reaches minimum specified operating voltage Propagation Delay (tpd ) The time interval between a) when the input current reaches 20% of it’s final value, and b) when the differential output reaches 20% of its final value. t2= time at which output voltage settles within ±10% of its steady state value under an applied magnetic field Response Time (tRESPONSE) The time interval between a) when the applied current reaches 90% of its final value, and b) when the sensor differential output reaches 90% of its final value corresponding to the applied current. 0 t Rise Time and Propagation Delay Response Time (%) 90 (%) 90 Primary Current VIOUTdiff Primary Current VIOUTdiff Rise Time, t r Response Time, t RESPONSE 0 t 20 10 0 t Propagation Delay, t pd Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 13 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain ACS726 PACKAGE OUTLINE DRAWING For Reference Only – Not for Tooling Use (Reference JEDEC MO-137 AE) 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 0.40 8.66 ±0.10 0.635 8º 0º 24 0.25 0.15 3.91 ±0.10 2.30 5.00 5.99 ±0.20 1.27 0.41 A 1.04 REF 1 2 0.25 BSC Branded Face 24X C 1.75 MAX 0.20 C B PCB Layout Reference View SEATING PLANE GAUGE PLANE SEATING PLANE 0.30 0.20 0.25 MAX 0.635 BSC NNNNNNNNNNNNN TLF-AAA LLLLLLLLLLL A Terminal #1 mark area B Reference pad layout (reference IPC7351 SOP63P600X175-24M) All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances C Branding scale and appearance at supplier discretion C PCB Layout Reference View N = Device part number T = Temperature code LF = (Literal) Package type A = Amperage Package LF, 24-Pin QSOP Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 14 Galvanically Isolated Current Sensor IC With Differential Output and Externally Adjustable Gain ACS726 Document Revision History Revision Date – April 3, 2014 1 August 13. 2014 Change Initial release Removed “A” deisgnator from part number and reformatted document Copyright ©2012-2014, Allegro MicroSystems, LLC Allegro MicroSystems, LLC 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, Allegro MicroSystems, LLC assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 15