A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch FEATURES AND BENEFITS DESCRIPTION * AEC-Q100 automotive qualified * Omnipolar operation * Low switchpoint drift * Superior temperature stability * Insensitive to physical stress * Reverse-battery protection * Robust EMC capability * Robust ESD protection The A1126 integrated circuit is an omnipolar, ultrasensitive Hall-effect switch with a digital output. This device has an integrated regulator permitting operation to 24 V. This device is especially suited for operation through extended temperature ranges, up to 150C. Superior high-temperature performance is made possible through a dynamic offset cancellation technique, which reduces the residual offset voltage normally caused by device overmolding, temperature excursions, and thermal stress. PACKAGES: The A1126 Hall-effect switch includes the following on a single silicon chip: voltage regulator, Hall-voltage generator, small-signal amplifier, chopper stabilization, Schmitt trigger, and a short-circuit-protected open-drain output. Advanced BiCMOS wafer fabrication processing is used to take advantage of low-voltage requirements, component matching, very low input-offset errors, and small component geometries. Not to scale NOT FOR NEW DESIGN 3-pin SOT23W (suffix LH) 3-pin SIP, matrix HD style (suffix UA) 3-pin SIP, chopper style (suffix UA) The omnipolar operation of the A1126 allows activation with either a north or a south polarity field of sufficient strength. In the absence of a magnetic field, the output is off. This patented magnetic-polarity-independence feature makes this device an excellent replacement for reed switches, with improved ease of manufacturing, because the A1126 does not require Continued on the next page... Functional Block Diagram VOUT VCC Dynamic Offset Cancellation Regulator To all subcircuits Omnipolar Switchpoints Amplifier Signal Recovery Control Current Limit GND A1126-DS, Rev. 3 October 28, 2016 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch DESCRIPTION (CONTINUED) manufacturers to orient their magnets. These devices allow simple on/off switching in industrial, consumer, and automotive applications. a miniature low-profile surface-mount package, while package UA is a three-lead ultra-mini SIP for through-hole mounting. Each package is lead (Pb) free, with 100% matte-tin-plated leadframe. The A1126 is rated for operation between the ambient temperatures -40C to 150C. The available package styles provide magnetically optimized solutions for most applications. Package LH is an SOT23W, SELECTION GUIDE Part Number Packing [1] Package A1126LLHLT-T [2] 3,000 pieces per reel A1126LLHLX-T 10,000 pieces per reel 3-pin SOT-23W surface mount A1126LUA-T [3] 500 pieces per bag 3-pin ultramini SIP through-hole mount 3-pin SOT-23W surface mount 1 Contact AllegroTM for additional packing options through authorized Allegro distributors only. 3 The chopper-style UA package is not for new design; the matrix HD style UA package is recommended for new designs. 2 Available ABSOLUTE MAXIMUM RATINGS Characteristic Symbol Notes Rating Unit Forward Supply Voltage VCC 28 V Reverse Supply Voltage VRCC -18 V Output Off Voltage VOUT 28 V Reverse Supply Current IRCC -2 mA Continuous Output Current IOUT Internally limited - Operating Ambient Temperature TA -40 to 150 C Maximum Junction Temperature TJ(max) 165 C Tstg -65 to 170 C Storage Temperature L temperature range Pinout Diagrams Terminal List Table 3 Name 1 2 LH Package 3-Pin SOT23W 1 2 Number Function LH UA VCC 1 1 Connects power supply to chip VOUT 2 3 Output from circuit GND 3 2 Ground 3 UA Package 3-Pin SIP Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 2 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch OPERATING CHARACTERISTICS: Valid through TA and VCC ranges, TJ < TJ(max), CBYP = 0.1 F, unless otherwise specified Characteristics Symbol Test Conditions Min. Typ. Max. Unit [1] ELECTRICAL CHARACTERISTICS Supply Voltage Output Leakage Current Output On Voltage VCC Operating, TJ < 165C 3 - 24 V IOUTOFF VOUT = 24 V, B < BRPS - - 10 A VOUT(SAT) IOUT = 20 mA, B > BOP - 185 500 mV B > BOP 30 - 60 mA - - 25 s Output Current Limit IOM Power-On Time [2][3] tPO Chopping Frequency fC - 800 - kHz Output Rise Time [3][4] tr RLOAD = 820 , CS = 20 pF - 0.2 2 s tf RLOAD = 820 , CS = 20 pF - 0.1 2 s B > BOP , VCC = 12 V - - 4 mA Output Fall Time [3][4] Supply Current Supply Zener Clamp Voltage Supply Zener Current ICC(ON) ICC(OFF) VZ IZSUPPLY B < BRP , VCC = 12 V - - 4 mA ICC = 6.5 mA; TA = 25C 28 - - V VS = 28 V - - 6.5 mA MAGNETIC CHARACTERISTICS Operate Point Release Point Hysteresis BOPS South pole adjacent to branded face 15 38 55 G BOPN North pole adjacent to branded face -55 -38 -15 G BRPS South pole adjacent to branded face 5 20 50 G BRPN North pole adjacent to branded face -50 -20 -5 G BHYS | BOPS - BRPS |, | BOPN - BRPN | 5 - 30 G 11 G (gauss) = 0.1 mT (millitesla). < BRP (min) - 10 G , B > BOP (max) + 10 G. 3 Guaranteed by device design and characterization. 4 C = oscilloscope probe capacitance. S 2B Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 3 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch Characteristic Performance Average Supply Current (On) versus Temperature Average Supply Current (On) versus Supply Voltage 4.0 Supply Current, ICC(ON) (mA) Supply Current, ICC(ON) (mA) 4.0 3.5 VCC = 24 V 3.0 2.5 VCC = 3.0 V 2.0 1.5 1.0 0.5 0 -60 -40 -20 0 20 40 60 80 100 120 140 3.5 2.5 TA = 25C 2.0 1.5 1.0 0.5 0 160 0 5 Average Supply Current (Off) versus Temperature 15 20 25 Average Supply Current (Off) versus Supply Voltage 4.0 Supply Current, ICC(OFF) (mA) 4.0 Supply Current, ICC(OFF) (mA) 10 Supply Voltage, VCC (V) Ambient Temperature, TA (C) 3.5 3.0 VCC = 24 V 2.5 2.0 VCC = 3.0 V 1.5 1.0 0.5 0 -60 TA = 150C TA = -40C 3.0 -40 -20 0 20 40 60 80 100 Ambient Temperature, TA (C) 120 140 160 3.5 3.0 TA = 150C TA = -40C 2.5 2.0 TA = 25C 1.5 1.0 0.5 0 0 5 10 15 20 25 Supply Voltage, VCC (V) Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 4 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch Average Operate Point (South) versus Supply Voltage 55 55 50 50 Operate Point (BOP) Applied Flux Density (G) Operate Point (BOP) Applied Flux Density (G) Average Operate Point (South) versus Temperature 45 40 35 VCC = 3.0 V 30 VCC = 24 V 25 20 15 -60 -40 -20 0 20 40 60 80 100 120 140 45 40 TA = 25C 25 20 0 5 50 50 45 45 40 35 30 VCC = 3.0 V 15 VCC = 24 V 10 5 -60 -40 -20 0 20 40 60 80 100 Ambient Temperature, TA (C) 15 20 25 Average Release Point (South) versus Supply Voltage Release Point (BRP) Applied Flux Density (G) Release Point (BRP) Applied Flux Density (G) Average Release Point (South) versus Temperature 20 10 Supply Voltage, VCC (V) Ambient Temperature, TA (C) 25 TA = 150C 30 15 160 TA = -40C 35 120 140 160 40 35 30 25 TA = 150C TA = -40C 20 15 TA = 25C 10 5 0 5 10 15 20 25 Supply Voltage, VCC (V) Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 5 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch Average Operate Point (North) versus Supply Voltage -15 -15 -20 -20 Operate Point (BOP) Applied Flux Density (G) Operate Point (BOP) Applied Flux Density (G) Average Operate Point (North) versus Temperature -25 -30 VCC = 24 V -35 VCC = 3.0 V -40 -45 -50 -55 -60 -40 -20 0 20 40 60 80 100 120 140 -25 -35 -45 -50 0 5 -5 -5 -10 -10 VCC = 24 V -20 VCC = 3.0 V -30 -35 -40 -45 -50 -60 -40 -20 0 20 40 60 80 100 Ambient Temperature, TA (C) 15 20 25 Average Release Point (North) versus Supply Voltage Release Point (BRP) Applied Flux Density (G) Release Point (BRP) Applied Flux Density (G) Average Release Point (North) versus Temperature -25 10 Supply Voltage, VCC (V) Ambient Temperature, TA (C) -15 TA = 150C TA = -40C -40 -55 160 TA = 25C -30 120 140 160 TA = -40C -15 -20 TA = 25C -25 TA = 150C -30 -35 -40 -45 -50 0 5 10 15 20 25 Supply Voltage, VCC (V) Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 6 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch Average Hysteresis (South) versus Supply Voltage Average Hysteresis (South) versus Temperature 30 Switchpoint Hysteresis (BHYS) Applied Flux Density (G) Switchpoint Hysteresis (BHYS) Applied Flux Density (G) 30 25 20 15 VCC = 3.0 V VCC = 24 V 10 5 -60 -40 -20 0 20 40 60 80 100 120 140 25 20 TA = -40C 15 10 TA = 150C 5 0 160 5 15 20 25 Average Hysteresis (North) versus Supply Voltage Average Hysteresis (North) versus Temperature 30 Switchpoint Hysteresis (BHYS) Applied Flux Density (G) 30 25 20 15 VCC = 24 V VCC = 3.0 V 10 -40 -20 0 20 40 60 80 100 120 140 25 20 TA = -40C 15 TA = 25C 10 TA = 150C 5 0 160 5 Ambient Temperature, TA (C) 10 15 20 25 Supply Voltage, VCC (V) Average Output Saturation Voltage versus Temperature IOUT = 20 mA, VCC = 12 V, B > BOP 500 Output Saturation Voltage VOUT(SAT), (mV) Switchpoint Hysteresis (BHYS) Applied Flux Density (G) 10 Supply Voltage, VCC (V) Ambient Temperature, TA (C) 5 -60 TA = 25C 450 400 350 300 250 200 150 100 50 0 -60 -40 -20 0 20 40 60 80 100 120 140 160 Ambient Temperature, TA (C) Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 7 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch THERMAL CHARACTERISTICS: May require derating at maximum conditions; see application information Characteristic Symbol Test Conditions* Value Units 228 C/W 110 C/W 165 C/W Package LH, 1-layer PCB with copper limited to solder pads RJA Package Thermal Resistance Package LH, 2-layer PCB with 0.463 nected by thermal vias in.2 of copper area each side con- Package UA, 1-layer PCB with copper limited to solder pads *Additional thermal information available on Allegro Web site. Maximum Allowable VCC (V) Power Derating Curve 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 VCC(max) 2-layer PCB, Package LH (RJA = 110 C/W) 1-layer PCB, Package UA (RJA = 165 C/W) 1-layer PCB, Package LH (RJA = 228 C/W) 20 40 60 80 100 120 VCC(min) 140 160 180 Temperature (C) Power Dissipation, PD (m W) Power Dissipation versus Ambient Temperature 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 2l (R aye rP J C A = 11 B, P 0 ac 1-la C/ ka y W (R er PC ) ge L JA = B H 165 , Pac k C/ a W) ge U A 1-lay er P (R CB, JA = 228 Packag C/W e LH ) 20 40 60 80 100 120 Temperature (C) 140 160 180 Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 8 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch FUNCTIONAL DESCRIPTION The output of these devices switches low (turns on) when a magnetic field perpendicular to the Hall sensor chip exceeds the operate point threshold, BOPx . After turn-on, the output voltage is VOUT(SAT) . The output transistor is capable of sinking current up to the short circuit current limit, IOM , which is a minimum of 30 mA. When the magnetic field is reduced below the release point, BRPx , the device output goes high (turns off). The difference in the magnetic operate and release points is the hysteresis, BHYS , of the device. This built-in hysteresis allows clean switch- ing of the output even in the presence of external mechanical vibration and electrical noise. In the case of omnipolar switch devices, removal of the magnetic field results in the device output high (off). Powering-on the device in the hysteresis range (less than BOPx and greater than BRPx ) will allow an indeterminate output state. The correct state is attained after the first excursion beyond BOPx or BRPx . V+ Switch to High VOUT VOUT(SAT) BHYS BRPS 0 BOPS BOPN B- BRPN 0 Switch to Low Switch to Low Switch to High VS B+ BHYS Figure 1. Switching behavior of omnipolar switches. On the horizontal axis, the B+ direction indicates increasing south polarity magnetic field strength, and the B- direction indicates increasing north polarity. This behavior can be exhibited when using a circuit such as that shown in figure 2. Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 9 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch APPLICATION INFORMATION V+ VCC RLOAD A1126 CBYPASS 0.1 F VOUT GND Figure 2. Typical Application Circuit Chopper Stabilization Technique When using Hall-effect technology, a limiting factor for switchpoint accuracy is the small signal voltage developed across the Hall element. This voltage is disproportionally small relative to the offset that can be produced at the output of the Hall sensor chip. This makes it difficult to process the signal while maintaining an accurate, reliable output over the specified operating temperature and voltage ranges. Chopper stabilization is a unique approach used to minimize Hall offset on the chip. The Allegro technique, namely Dynamic Quadrature Offset Cancellation, removes key sources of the output drift induced by thermal and mechanical stresses. This offset reduction technique is based on a signal modulation-demodulation process. The undesired offset signal is separated from the magnetic field-induced signal in the frequency domain, through modulation. The subsequent demodulation acts as a modulation process for the offset, causing the magnetic field-induced signal to recover its original spectrum at baseband, while the DC offset becomes a high-frequency signal. The magnetic-sourced signal then can pass through a low-pass filter, while the modulated DC offset is suppressed. The chopper stabilization technique uses a 400 kHz high frequency clock. For demodulation process, a sample-and-hold technique is used, where the sampling is performed at twice the chopper frequency. This high-frequency operation allows a greater sampling rate, which results in higher accuracy and faster signal-processing capability. This approach desensitizes the chip to the effects of thermal and mechanical stresses, and produces devices that have extremely stable quiescent Hall output voltages and precise recoverability after temperature cycling. This technique is made possible through the use of a BiCMOS process, which allows the use of low-offset, low-noise amplifiers in combination with highdensity logic integration and sample-and-hold circuits. Regulator Hall Element Amp Sample and Hold Clock/Logic Low-Pass Filter Figure 3. Concept of Chopper Stabilization Technique Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 10 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch Power Derating The device must be operated below the maximum junction temperature of the device, TJ(max) . Under certain combinations of peak conditions, reliable operation may require derating supplied power or improving the heat dissipation properties of the application. This section presents a procedure for correlating factors affecting operating TJ. (Thermal data is also available on the Allegro MicroSystems Web site.) The Package Thermal Resistance, RJA, is a figure of merit summarizing the ability of the application and the device to dissipate heat from the junction (die), through all paths to the ambient air. Its primary component is the Effective Thermal Conductivity, K, of the printed circuit board, including adjacent devices and traces. Radiation from the die through the device case, RJC, is relatively small component of RJA. Ambient air temperature, TA, and air motion are significant external factors, damped by overmolding. The effect of varying power levels (Power Dissipation, PD), can be estimated. The following formulas represent the fundamental relationships used to estimate TJ, at PD. PD = VIN x IIN (1) T = PD x RJA (2) TJ = TA + T (3) Example: Reliability for VCC at TA = 150C, package UA, using a single-layer PCB. Observe the worst-case ratings for the device, specifically: RJA = 165C/W, TJ(max) = 165C, VCC(max) = 24 V, and ICC(max) = 4 mA. Calculate the maximum allowable power level, PD(max) . First, invert equation 3: Tmax = TJ(max) - TA = 165 C - 150 C = 15 C This provides the allowable increase to TJ resulting from internal power dissipation. Then, invert equation 2: PD(max) = Tmax / RJA = 15C / 165C/W = 91 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) /ICC(max) = 91 mW / 4 mA = 23 V The result indicates that, at TA, the application and device can dissipate adequate amounts of heat at voltages VCC(est) . Compare VCC(est) to VCC(max) . If VCC(est) VCC(max) , then reliable operation between VCC(est) and VCC(max) requires enhanced RJA. If VCC(est) VCC(max) , then operation between VCC(est) and VCC(max) is reliable under these conditions. For example, given common conditions such as: TA= 25C, VIN = 12 V, IIN = 4 mA, and RJA = 140C/W, then: PD = VIN x IIN = 12 V x 4 mA = 48 mW T = PD x RJA = 48 mW x 140C/W = 7C TJ = TA + T = 25C + 7C = 32C A worst-case estimate, PD(max) , represents the maximum allowable power level, without exceeding TJ(max) , at a selected RJA and TA. Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 11 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch Package LH, 3-Pin SOT23W +0.12 2.98 -0.08 1.49 D 44 3 A +0.020 0.180-0.053 0.96 D +0.10 2.90 -0.20 +0.19 1.91 -0.06 2.40 0.70 D 0.25 MIN 1.00 2 1 0.55 REF 0.25 BSC 0.95 Seating Plane Gauge Plane 8X 10 REF B PCB Layout Reference View Branded Face 1.00 0.13 0.95 BSC +0.10 0.05 -0.05 0.40 0.10 NNN 1 C Standard Branding Reference View N = Last three digits of device part number For Reference Only; not for tooling use (reference DWG-2840) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Active Area Depth, 0.28 mm REF B Reference land pattern layout 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 D Hall element, not to scale Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 12 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch Package UA, 3-Pin SIP, Matrix Style +0.08 4.09 -0.05 45 B E C 2.04 1.52 0.05 +0.08 3.02 -0.05 1.44 E 10 Mold Ejector Pin Indent E Branded Face A 1.02 MAX 45 0.79 REF NNN 1 1 2 D Standard Branding Reference View 3 = Supplier emblem N = Last three digits of device part number +0.03 0.41 -0.06 14.99 0.25 +0.05 0.43 -0.07 For Reference Only; not for tooling use (reference DWG-9065) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Dambar removal protrusion (6X) B Gate and tie bar burr area C Active Area Depth, 0.50 mm REF D Branding scale and appearance at supplier discretion E Hall element (not to scale) 1.27 NOM Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 13 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch Package UA, 3-Pin SIP, Chopper Style +0.08 4.09 -0.05 45 B C E 2.04 1.52 0.05 1.44 E Mold Ejector Pin Indent +0.08 3.02 -0.05 E Branded Face 45 1 2.16 MAX D Standard Branding Reference View = Supplier emblem N = Last three digits of device part number 0.79 REF 0.51 REF NNN A 1 2 3 NOT FOR NEW DESIGN +0.03 0.41 -0.06 15.75 0.51 For Reference Only; not for tooling use (reference DWG-9049) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Dambar removal protrusion (6X) B Gate burr area C Active Area Depth, 0.50 mm REF +0.05 0.43 -0.07 D Branding scale and appearance at supplier discretion E Hall element, not to scale 1.27 NOM Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 14 A1126 Chopper-Stabilized Omnipolar Hall-Effect Switch Revision History Number Date 1 September 16, 2013 Update UA package drawing Description 2 September 21, 2015 Added AEC-Q100 qualification under Features and Benefits 3 October 28, 2016 Chopper-style UA package designated as not for new design Copyright (c)2018, 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. Copies of this document are considered uncontrolled documents. For the latest version of this document, visit our website: www.allegromicro.com Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 15