A1688LUBTN-L-T

A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC 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: October 1, 2022 Recommended Substitutions: For existing customer transition, and for new customers or new applications, refer to the A19200LUBATN-L, A19200LUBATN-H, or A19250LUBATN. NOTE: For detailed information on purchasing options, contact your local Allegro field applications engineer or sales representative. Allegro MicroSystems 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 assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC FEATURES AND BENEFITS • Integrated capacitor reduces need for external EMI protection components • Wide leads facilitate ease of assembly • True zero-speed operation • Automatic Gain Control (AGC) for air gap independent switch points • Automatic Offset Adjustment (AOA) for signal processing optimization • Large operating air gap range • Internal current regulator for two-wire operation • Undervoltage lockout • Single chip sensing IC for high reliability • On-chip voltage regulator with wide operating voltage range and stability in the presence of a variety of complex load impedances • Fully synchronous digital logic with Scan and IDDQ testing PACKAGE: 2-pin SIP (suffix UB) DESCRIPTION The A1688 is a Hall-effect-based integrated circuit (IC) that provides a user-friendly solution for true zero-speed digital ring magnet and gear tooth sensing in two-wire applications. The A1688 is offered in the UB package, which integrates the IC and a high temperature ceramic capacitor in a single overmolded SIP package. The integrated capacitor provides enhanced EMC performance with reduced external components. The integrated circuit incorporates a dual-element Hall-effect circuit and signal processing that switches in response to differential magnetic signals created by magnetic encoders, or, when properly back-biased with a magnet, from ferromagnetic targets. The device contains a sophisticated digital circuit that reduces magnet and system offsets, calibrates the gain for air gap independent switch points, and provides true zero-speed operation. Signal optimization occurs at power-up through the combination of offset and gain-adjust and is maintained throughout operation with the use of a running-mode calibration scheme. Runningmode calibration provides immunity from environmental effects such as micro-oscillations of the sensed target or sudden air gap changes. The regulated current output is configured for two-wire interface circuitry and is ideally suited for obtaining speed information in wheel speed applications. The Hall element spacing is optimized for high resolution, small diameter targets. The package is lead (Pb) free, with 100% matte-tin leadframe plating. Not to scale VCC Internal Regulator Amp Offset Adjust AGC Analog to Digital Converter Digital Controller Output Control GND Chopper Stabilization Functional Block Diagram A1688-DS, Rev. 10 MCO-0000633 October 1, 2022 A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC SPECIFICATIONS SELECTION GUIDE Part Number Packing* Power-On State A1688LUBTN–L–T 4000 pieces per 13-in. reel ICC(LOW) A1688LUBTN–H–T 4000 pieces per 13-in. reel ICC(HIGH) *Contact Allegro™ for additional packing options. ABSOLUTE MAXIMUM RATINGS Characteristic Symbol Notes Rating Unit Supply Voltage VCC 28 V Reverse Supply Voltage VRCC –18 V Operating Ambient Temperature TA –40 to 150 ºC Maximum Junction Temperature TJ(max) 165 ºC Tstg –65 to 170 ºC Value (Typ.) Unit 2200 pF Storage Temperature L temperature range Internal Discrete Capacitor Ratings Characteristic Symbol Nominal Capacitance CSUPPLY Test Conditions* Connected between VCC and GND Terminal List Table 1 2 Name Number Function VCC 1 Supply Voltage GND 2 Ground UB Package, 2-Pin SIP Pinout Diagram Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 2 A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC OPERATING CHARACTERISTICS: Valid throughout full operating and temperature ranges; unless otherwise specified Characteristic Symbol Test Conditions Min. Typ.1 Max. Unit Operating, TJ < TJ(max) 4 – 24 V VCC transitioning from 0 → 5 V or 5 → 0 V – 3.6 3.95 V VCC = VRCC(max) – – –10 mA ELECTRICAL CHARACTERISTICS Supply Voltage2 Undervoltage Lockout Reverse Supply Current3 VCC VCC(UV) IRCC Supply Zener Clamp Voltage VZSUPPLY ICC = ICC(max) + 3 mA, TA = 25ºC 28 – – V Supply Zener Current IZSUPPLY TA = 25°C, VCC = 28 V – – 19 mA -H variant – ICC(HIGH) – – OUTPUT Power-On State Supply Current POS – ICC(LOW) – – ICC(LOW) -L variant Low-current state 5.9 – 8.4 mA ICC(HIGH) High-current state 12 – 16 mA ICC(HIGH) / ICC(LOW) Measured as ratio of high current to low current (isothermal) 1.9 – – – Output Rise Time tr Corresponds to measured output slew rate with CSUPPLY; RLOAD = 100 Ω 0 – 1.5 μs Output Fall Time tf Corresponds to measured output slew rate with CSUPPLY; RLOAD = 100 Ω 0 – 1.5 μs Supply Current Ratio OPERATING CHARACTERISTICS Operate Point BOP % of peak-to-peak IC-processed magnetic signal – 60 – % Release Point BRP % of peak-to-peak IC-processed magnetic signal – 40 – % Operating Frequency fFWD 0 – 5 kHz Continued on the next page… VCC 1 VCC A1688 GND 4 RLOAD 100 Ω CLOAD Figure 1: Typical Application Circuit Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 3 A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC OPERATING CHARACTERISTICS (continued): Valid throughout full operating and temperature ranges; unless otherwise specified Characteristic Symbol Test Conditions Min. Typ.1 Max. Unit 20 – 1200 G –300 – 300 G – +0.2 – %/°C OPERATING CHARACTERISTICS (continued) Input Signal BSIG Allowable User-Induced Differential Offset BSIGEXT Sensitivity Temperature Coefficient4 TC Differential signal, measured peak-to-peak External differential signal bias (DC), operating within specification Total Pitch Deviation For constant BSIG, sine wave – – ±2 % Maximum Sudden Signal Amplitude Change BSEQ(n+1) / BSEQ(n) No missed output edge. Instantaneous symmetric magnetic signal amplitude change, measured as a percentage of peak-to-peak BSIG (see figure 2) – 0.6 – – Maximum Total Signal Amplitude Change BSEQ(max) / BSEQ(min) Overall symmetric magnetic signal amplitude change, measured as a percentage of peak-topeak BSIG – 0.2 – – – 400 – kHz Front-End Chopping Frequency 1 Typical values are at TA = 25°C and VCC = 12 V. Performance may vary for individual units, within the specified maximum and minimum limits. voltage must be adjusted for power dissipation and junction temperature; see representative discussions in Power Derating section. current is defined as conventional current coming out of (sourced from) the specified device terminal. 4 Ring magnets decrease strength with rising temperature. Device compensates. Note that B SIG requirement is not influenced by this. 2 Maximum 3 Negative BSEQ(n) BSEQ(n+1) Figure 2: Differential Signal Variation Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 4 A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC THERMAL CHARACTERISTICS Characteristic Symbol Package Thermal Resistance RθJA Test Conditions* Single-layer PCB with copper limited to solder pads Value Unit 213 ºC/W *Additional thermal information is available on the Allegro website. 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) VCC(min) 20 40 60 80 100 120 140 160 180 Temperature (ºC) Power Dissipation PD (mW) 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 20 40 60 80 100 120 140 160 180 Temperature (ºC) Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 5 A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC FUNCTIONAL DESCRIPTION Hall Technology Determining Output Signal Polarity This single-chip differential Hall-effect sensor IC contains two Hall elements as shown in Figure 5, which simultaneously sense the magnetic profile of the ring magnet or gear target. The magnetic fields are sensed at different points (spaced at a 1.75 mm pitch), generating a differential internal analog voltage, VPROC , that is processed for precise switching of the digital output signal. In Figure 5, the top panel, labeled Mechanical Position, represents the mechanical features of the ring magnet or gear target and orientation to the device. The bottom panel, labeled Device Output Signal, displays the square waveform corresponding to the digital output signal that results from a rotating target configured as shown in Figure 4. That direction of rotation (of the target side adjacent to the package face) is: perpendicular to the leads, across the face of the device, from the pin 1 side to the pin 2 side. This results in the device output switching from high to low output state as a north magnetic pole passes the device face. In this configuration, the device output voltage switches to its high polarity when a south pole is the target feature nearest to the device. If the direction of rotation is reversed or if a part of type A1688LUBxx-L-x is used, then the output polarity inverts (see Table 1). The Hall IC is self-calibrating and also possesses a temperaturecompensated amplifier and offset cancellation circuitry. Its voltage regulator provides supply noise rejection throughout the operating voltage range. Changes in temperature do not greatly affect this device due to the stable amplifier design and the offset rejection circuitry. The Hall transducers and signal processing electronics are integrated on the same silicon substrate, using a proprietary BiCMOS process. Target Profiling During Operation An operating device is capable of providing digital information that is representative of the mechanical features of a rotating gear or ring magnet. The waveform diagram in Figure 5 presents the automatic translation of the mechanical profile, through the magnetic profile that it induces, to the digital output signal of the A1688. No additional optimization is needed, and minimal processing circuitry is required. This ease of use reduces design time and incremental assembly costs for most applications. Ring Magnet Target S N S Ferromagnetic Target N Tooth Pin 2 Side Back-Biasing Magnet (Externally applied for ferromagnetic target) IC Table 1: Output Polarity when a South Pole Passes the Package Face in the Indicated Rotation Direction Part Type Rotation Direction A1688LUBxx-H-x Pin 1 (Top View of Side Package Case) South Pole North Pole A1688LUBxx-L-x Pin 1 → Pin 2 ICC(HIGH) ICC(LOW) Pin 2 → Pin 1 ICC(LOW) ICC(HIGH) Rotating Target (Ring magnet or ferromagnetic) Branded Face of Package S N S N S SN N Pin 1 Valley Element Pitch Hall Element 1 Hall Element 2 Package Case Branded Face Pin 2 Rotation from pin 1 to pin 2 Branded Face of Package Rotating Target (Ring magnet or ferromagnetic) S N S N S S N Pin 1 N Pin 2 Rotation from pin 2 to pin 1 Figure 3: Relative Motion of the Target Relative Motion of the Target is detected by the dual Hall elements mounted on the Hall IC. Figure 4: Target Orientation Relative to Device (ring magnet shown). Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 6 A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC N Element Pitch Device Orientation to Target (Pin 2 Side) E2 Package Case Branded Face IC E1 (Pin 1 Side) (Top View of Package Case) Mechanical Position (Target moves past device pin 1 to pin 2) Target (Radial Ring Magnet) N Target Magnetic Profile +B This pole sensed later N S (Pin 2 Side) Package Case Branded Face E2 IC (Pin 1 Side) E1 North Pole Mechanical Position (Target moves past device pin 1 to pin 2) Target (Ferromagnetic) This tooth sensed earlier Target Magnetic Profile Element Pitch (Top View of Package Case) South Pole External Back-Biasing Magnet Element Pitch This pole sensed earlier Device Orientation to Target This tooth sensed later Speed Channel Element Pitch +B –B IC Internal Differential Analog Signals, VPROC Speed Channel BOP(#1) IC Internal Differential Analog Signals, VPROC BOP(#2) BOP(#1) BRP(#1) BOP(#2) BRP(#1) Device Output Signal,IOUT Device Output Signal,IOUT +t +t Figure 5: Basic Operation Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 7 A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC 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 website.) The Package Thermal Resistance, RθJA, 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, RθJC, is relatively small component of RθJA. 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.  A worst-case estimate, PD(max), represents the maximum allowable power level (VCC(max), ICC(max)), without exceeding TJ(max), at a selected RθJA and TA. Example: Reliability for VCC at TA = 150°C, package UB, using minimum-K PCB. Observe the worst-case ratings for the device, specifically: RθJA = 213°C/W, TJ(max)  = 165°C, VCC(max) = 24 V, and ICC(max)  = 16 mA. Calculate the maximum allowable power level, PD(max). First, invert equation 3: ΔTmax = 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) = ΔTmax ÷ RθJA = 15°C ÷ 213 °C/W = 64.9 mW Finally, invert equation 1 with respect to voltage: PD = VIN × IIN (1) VCC(est) = PD(max) ÷  ICC(max) = 64.9 mW ÷ 16.0 mA = 4.05 V ΔT = PD × RθJA (2) TJ = TA + ΔT (3) The result indicates that, at TA, the application and device can dissipate adequate amounts of heat at voltages ≤VCC(est). For example, given common conditions such as: TA= 25°C, VCC = 12 V, ICC = 14 mA, and RθJA = 213 °C/W, then: Compare VCC(est) to VCC(max). If VCC(est) ≤ VCC(max), then reliable operation between VCC(est) and VCC(max) requires enhanced RθJA. If VCC(est) ≥ VCC(max), then operation between VCC(est) and VCC(max) is reliable under these conditions. PD = VCC × ICC = 12 V × 14 mA = 168 mW ΔT = PD × RθJA = 168 mW × 213 °C/W = 38.8°C  TJ = TA + ΔT = 25°C + 38.8°C = 63.8°C Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 8 A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC PACKAGE OUTLINE DRAWING For Reference Only – Not for Tooling Use (Reference DWG-0000408, Rev. 3) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown +0.06 4.00 –0.05 B 4 × 10° E 1.75 1.50 ±0.05 E 1.125 C 1.45 E 4.00 +0.06 –0.07 E E1 Mold Ejector Pin Indent E2 E Branded Face A 4 × 2.50 REF 0.25 REF 0.30 REF NNN YYWW LLLL 45° 0.85 ±0.05 0.42 ±0.10 D Standard Branding Reference View 2.54 REF N Y W L 4 × 0.85 REF 1 18.00 ±0.10 2 1.00 ±0.10 12.20 ±0.10 +0.07 0.25 –0.03 4 × 7.37 REF 1.80 ±0.10 = Supplier emblem = Last three digits of device part number = Last 2 digits of year of manufacture = Week of manufacture = Lot number A Dambar removal protrusion (8×) B Gate and tie bar burr area C Active Area Depth, 0.38 mm ±0.03 D Branding scale and appearance at supplier discretion E Hall elements (E1 and E2); not to scale F Molded Lead Bar for preventing damage to leads during shipment 0.38 REF 0.25 REF 4 × 0.85 REF 0.85 ±0.05 1.80 +0.06 –0.07 F 4.00 +0.06 –0.05 1.50 ±0.05 Figure 6: Package UB, 2-Pin SIP Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 9 A1688 Two-Wire, True Zero-Speed, High Accuracy Sensor IC Revision History Number Date – March 18, 2014 Initial release. No change from Preliminary Rev. 2.6 Description 1 October 1, 2014 Revised Package Outline Drawing and reformatted datasheet 2 November 10, 2014 Deleted redundant Thermal Characteristics table from page 2 3 December 15, 2014 Corrected error on Package Outline Drawing 4 March 24, 2015 5 July 10, 2015 Removed bulk options from Selection Guide on page 2 6 March 1, 2016 Updated Internal Discrete Capacitor Ratings table and Package Outline Drawing 7 March 29, 2019 Minor editorial updates 8 April 9, 2020 Minor editorial updates 9 April 30, 2021 Updated Package Outline Drawing (page 9) 10 October 1, 2022 Change product status: Not for new design Updated branding on Package Outline Drawing Copyright 2022, Allegro MicroSystems. Allegro MicroSystems 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 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 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 10