A17501POKATN-PDFUYJEA

A17501 ALLEGRO | Alldatasheet

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The A17501 is a single IC solution designed for rotational position sensing of a ring magnet target found in automotive and industrial electric motor applications (often with specific application and safety requirements). Three Hall elements are incorporated to create two independent differential channels. These inputs are processed by digital circuits and robust algorithms designed to eliminate the detrimental effects of magnetic and system offsets, and to address false output transitions caused by target vibrations in electric motors at startup and low speed operation. The differential signals are used to produce a highly accurate speed output and, if desired, provide information on the direction of rotation. Advanced calibration techniques are used to optimize signal offset and amplitude. This calibration, combined with the digital tracking of the signal, results in accurate switch points over air gap, speed, and temperature. The IC can be programmed for a variety of applications requiring dual-phase target speed and position signal information or simultaneous high-resolution target speed and direction information. It can be configured to enable Fault Detection mode for ASIL B(D) utilization (assessment pending). The A17501 K package is a lead (Pb) free 4-pin SIP package with a 100% matte-tin-plated lead frame. A17501-DS MCO-0000793

High-speed switching bandwidth up to 40 kHz
Two independent output channels with options for high resolution XOR speed, pulse, and direction protocol
ASIL B(D) compliant (ISO 26262), assessment pending
Optional fault detection output protocol
Immune to common external magnetic disturbance
EEPROM enables factory traceability throughout product life cycle
Ideally suited for asynchronous electric motor applications
Also available with integrated magnet (see ATS17501 datasheet) Dual Output Differential Speed and Direction Sensor IC Functional Block Diagram A17501 FEATURES AND BENEFITS DESCRIPTION March 19, 2020 PACKAGE: Not to scale 4-Pin SIP (suffix K) Digital Controller Analog Regulator Temperature Sensor Oscillator EEPROM Diagnostics Digital Regulator Hall Elements OUTB GND OUTA VCC ADCAnalog Filter ADCAnalog Filter Gain Gain Advance Information Datasheet • Subject to Change Without Notice

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A. www.allegromicro.com SELECTION GUIDE [1] Part Number Packing A17501POKATN-SDFUYJE 4000 pieces per 13-inch reel [1] Not all selectable combinations are available, contact Allegro for additional selections and packing options. Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com ABSOLUTE MAXIMUM RATINGS Characteristic Symbol Notes Rating Unit Supply Voltage VCC Refer to Power Derating section 28 V Reverse Supply Voltage VRCC –18 V Output Voltage VOUT Each output pin 28 V Reverse Output Voltage VROUT Each output pin; RPULLUP ≥ 1 kΩ –0.5 V Output Sink Current IOUT Short-term output current for OUTA and OUTB independently, not intended for continuous operation 50 mA Operating Ambient Temperature Range TA –40 to 160 °C Junction Temperature TJ 175 °C Storage Temperature Range Tstg –65 to 170 °C K Package, 4-Pin SIP PINOUT TABLE Name Pin Function VCC 1 Supply Voltage OUTA 2 Configurable Output A OUTB 3 Configurable Output B GND 4 Ground PINOUT DIAGRAM 2 3 41 Branded Face Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com TYPICAL APPLICATION CIRCUIT VCC GND OUTA OUTB A17501 VSUPPLY VPULLUP [2] VOUT(B) VOUT(A) VPULLUP[2] RPULLUP(B) CLOAD(B) CLOAD(A) RPULLUP(A)RSERIES CBYPASS COMPONENTS [3] Characteristic Symbol Notes Value (Typ.) Unit Series Resistance RSERIES Recommended for typical EMC requirements 100 Ω OUTA Pullup Resistance RPULLUP(A) Required for functional operation; recommended value dependent on programming options 1 kΩ OUTB Pullup Resistance RPULLUP(B) Required for functional operation; recommended value dependent on programming options 1 kΩ Bypass Capacitance CBYPASS Recommended for typical EMC requirements 100 nF OUTA Load Capacitance CLOAD(A) Recommended for typical EMC requirements; required for certain programming options 2.2 nF OUTB Load Capacitance CLOAD(B) Recommended for typical EMC requirements; required for certain programming options 2.2 nF [2] VPULLUP may be connected to VCC if VCC meets VPULLUP requirements. See Operating Characteristics section. [3] Components listed are typical recommended values and are not suited for all applications and/or programmable options. See Operating Characteristics and Selection Guide for more information. Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Characteristic Symbol Test Conditions Min. Typ. [4] Max. Unit ELECTRICAL SUPPLY CHARACTERISTICS Supply Voltage [5] VCC Voltage across VCC and GND 4 – 24 V Undervoltage Lockout VCC(UV) – – 3.99 V Supply Current ICC – 10 15 mA Reverse Supply Current IRCC VCC = –18 V –10 – – mA ELECTRICAL PROTECTION CHARACTERISTICS Supply Clamp Voltage VCSUPPLY TA = 25°C; ICC = 18 mA 28 – – V Reverse Supply Clamp Voltage VRCSUPPLY TA = 25°C; ICC = –3 mA – – –18 V Output Clamp Voltage VCOUT TA = 25°C; IOUT = 3 mA 28 – – V Output Current Internal Limiter IOUT(LIM) Current limited by design for short circuit event on OUTA and OUTB independently; low impedance output state 30 55 85 mA POWER-ON CHARACTERISTICS Power-On State POS For OUTA and OUTB VOUT(HIGH) V Power-On Time tPO Time from VCC > VCC(min) to when sensor IC output is valid – – 1 ms CALIBRATION CHARACTERISTICS First Output Edge – Amount of target rotation with constant direction following power-on until first electrical output transition; Dynamic Threshold option; see Figure 1 – 1 – TCYCLE Initial Calibration – Amount of target rotation with constant direction following power-on until calibration is complete; Dynamic Threshold option; see Figure 1 – 2 – TCYCLE OUTPUT CHARACTERISTICS [6] Output Low Voltage VOUT(LOW) Fault Detection Mode disabled; IOUT = 10 mA – 0.165 0.35 V Fault Detection Mode enabled

5 V, 1 kΩ or 5 V, 3 kΩ

option 0.5 – 1.25 V 12 V, 1 kΩ option 1.2 – 3.6 V Output High Voltage VOUT(HIGH) Fault Detection Mode disabled – VPULLUP – V Fault Detection Mode enabled option 3.75 – 4.5 V 12 V, 1 kΩ option 8.4 – 10.8 V OPERATING CHARACTERISTICS : Valid throughout operating ranges, unless otherwise specified Continued on next page... [4] Typical values are at TA = 25°C and VCC = 5 V. Performance may vary for individual units, within the specified maximum and minimum limits. [5] Maximum voltage must be adjusted for power dissipation and junction temperature; see representative for Power Derating discussions. [6] Output characteristics are valid for each output independently, unless otherwise specified. Advance Information Datasheet Subject to Change Without Notice March 19, 2020

5 V, 1 kΩ or

5 V, 3 kΩ option

High fault (VFAULT(HIGH)) 4.5 – – V Mid fault (VFAULT(MID)) 1.25 – 3.75 V Low fault (VFAULT(LOW)) – – 0.5 V Fault Detection Mode enabled;

12 V, 1 kΩ option

High fault (VFAULT(HIGH)) 10.8 – – V Mid fault (VFAULT(MID)) 3.6 – 8.4 V Low fault (VFAULT(LOW)) – – 1.2 V Allowable Pullup Voltage VPULLUP Fault Detection Mode disabled 4 – 24 V Fault Detection Mode enabled 5 V, 1 kΩ or 5 V, 3 kΩ option 4.75 – 5.25 V 12 V, 1 kΩ option 11.4 – 12.6 V Allowable Pullup Resistor [10] RPULLUP Fault Detection Mode disabled – 1 – kΩ Fault Detection Mode enabled 5 V, 1 kΩ option 0.8 – 1.46 kΩ 5 V, 3 kΩ option 1.46 – 3.4 kΩ 12 V, 1 kΩ option 0.9 – 1.1 kΩ Allowable Load Capacitor [11] CLOAD Fault Detection Mode enabled 1 – – nF Output Leakage Current IOUT(OFF) Fault Detection Mode disabled; VOUT = VOUT(HIGH) – – 10 µA Duty Cycle D Speed output protocol; Dynamic Threshold option; sinusoidal input signal; fOP < 1 kHz 45 50 55 % Output Rise Time tr 10%→90%; VPULLUP = 5 V; RPULLUP = 1 kΩ; CLOAD = 2.2 nF – 5 – µs Output Fall Time tf 90%→10%; VPULLUP = 5 V; RPULLUP = 1 kΩ; CLOAD = 2.2 nF Fault Detection Mode disabled; Fast fall time option – 0.5 – µs Fault Detection Mode disabled; Slow fall time option – 3.5 – µs Fault Detection Mode enabled – 6 – µs Forward Pulse Width [12] tw(FWD) 38 45 52 µs Reverse Pulse Width [12] tw(REV) 76 90 104 µs Propagation Delay td Delay from the magnetic signal crossing a switch point threshold to the start of the output transition – 8 – µs Jitter [13] – σ×6; sinusoidal input signal; fOP = 1 kHz BDIFF(pk-pk) = 100 G – – 0.13 target degrees BDIFF(pk-pk) = 150 G – – 0.086 target degrees BDIFF(pk-pk) = 200 G – – 0.064 target degrees [7] Typical values are for VCC = 5 V and TA = 25°C, unless otherwise specified. [8] Output characteristics are valid for each output independently, unless otherwise specified. [9] Valid with Fault Detection Mode enabled and correct programming of the Fault Detection Load Circuit option; see Selection Guide. [10] See Application Circuit section. [11] Minimum capacitor required when Fault Detection Mode is enabled to ensure correct output levels over operating conditions. Increased load capacitance will directly impact maximum operating frequency due to the increased rise and fall times; see Application Circuit section. [12] Time from start of output transition from VOUT(HIGH) to VOUT(LOW) to start of output transition from VOUT(LOW) to VOUT(HIGH). Measured pulse width will vary with load circuit configurations and measure- ment thresholds. Valid with Pulse or Pulse Inverted output protocol; see Programming Options section. [13] Guaranteed by design and characterization only. Characterization performed by measuring greater than 1,000 falling output edges of the same target feature at constant temperature using Reference Target 60-0, see Reference Target Characteristics section. Value representative of a 6-σ distribution, such that 99.76% of the measured values are within the specified target degree. Continued on next page... Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com OPERATING CHARACTERISTICS (continued): Valid over operating ranges, unless otherwise specified Characteristic Symbol Test Conditions Min. Typ. [14] Max. Unit SWITCH POINT CHARACTERISTICS Operate Point BOP % of BDIFF(PKPK); VOUT = VOUT(LOW) → VOUT = VOUT(HIGH); Dynamic Threshold option – 70 – % Release Point BRP % of BDIFF(PKPK); VOUT = VOUT(HIGH) → VOUT = VOUT(LOW); Dynamic Threshold option – 30 – % Hysteresis BHYS ΔBDIFF after switch point to allow next output transition % of BDIFF(PKPK); Dynamic Threshold option – 40 – % Fixed Threshold option – 10 – G INPUT CHARACTERISTICS Operating Frequency fOP Sinusoidal input signal; forward and reverse target rotation; not valid for Pulse or Inverse Pulse output protocol 0 – 40 kHz Forward Pulse Operating Frequency fOP(FWD) Pulse or Inverse Pulse output protocol 0 – 9 kHz Reverse Pulse Operating Frequency fOP(REV) Pulse or Inverse Pulse output protocol 0 – 6 kHz Operating Magnetic Input [15] BDIFF(pk-pk) See Figure 2 Dynamic Threshold option; fOP ≤ 20 kHz 30 – – G Dynamic Threshold option; fOP > 20 kHz 40 – – G Fixed Threshold option 100 – – G Operating Magnetic Input Peak [15] BDIFF See Figure 2 –1150 – 1150 G Operating Magnetic Input Signal Variation [16] ΔBDIFF(pk-pk) Bounded amplitude ratio within TWINDOW; no missed output transitions; possible incorrect direction information and/or reduction in switch point accuracy; see Figure 3 and Figure 4 0.6 – 2 – Operating Magnetic Input Signal Variation Window TWINDOW Rolling window in which ΔBDIFF(pk-pk) cannot exceed bounded ratio; see Figure 3 and Figure 4 8 – – TCYCLE THERMAL CHARACTERISTICS Package Thermal Resistance RθJA Single-sided PCB, with copper limited to solder pads – 177 – °C/W [14] Typical values are for VCC = 5 V and TA = 25°C, unless otherwise specified. [15] Differential magnetic field is measured for Left Channel (E1-E2) and Right Channel (E2-E3) independently; see Package Diagram. Magnetic field is measured orthogonally to the branded package face. [16] Operating magnetic input variation is valid for symmetrical peak variation about the signal offset. BDIFF(pk-pk) must always be greater than BDIFF(pk-pk,min). Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com REFERENCE Typical Application Circuit TCYCLE Target BDIFF TCYCLE N S NSS Figure 1: Definition of TCYCLE TCYCLE = Target Cycle; the amount of rotation that moves one tooth and valley across the sensor. BDIFF = The differential magnetic flux density sensed by the IC. Differential Magnetic Input BDIFF(max) BDIFF(min) Time BDIFF BDIFF BDIFF(pk-pk) Figure 2: Differential Magnetic Input BDIFF = The differential magnetic flux density sensed by the IC. BDIFF(pk-pk) = The peak-to-peak magnetic flux density sensed by the IC. Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Figure 3: Repeated Period Variation Figure 4: Single Period Variation Operating Magnetic Signal Variation and Window Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com CHARACTERIZATION PLOTS [17] [17] Characterization data representative of distribution averages. Characterization tested with Dynamic Threshold algorithm at fOP = 1 kHz, VCC = 5 V , VPULLUP = 5 V , RPULLUP = 1 kΩ, and CLOAD = 2.2 nF unless otherwise specified. Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com FUNCTIONAL DESCRIPTION General As shown in Figure 5, the A17501 supports three Hall elements that sense the magnetic profile of the ring magnet target simulta- neously but at different points (each channel spaced at 1.75 mm pitch), generating two differential internal signals processed for precise switching of the digital output signals. Direction of rotation can be determined based on the phase relationship of the two differential internal signals. The A17501 is intended for use with ring magnet targets, or ferromagnetic targets when properly back-biased. The Hall-effect sensor IC is self-calibrating and possesses a tem- perature compensated amplifier as well as a full-range analog-to- digital converter (ADC). This allows for accurate processing of a wide range of target magnetic profile amplitudes and offsets. The on-chip voltage regulator provides supply noise rejection throughout the operating voltage range. Changes in tempera- ture do not greatly affect the A17501 due to the stable amplifier design and full-range ADC. The Hall elements and signal pro- cessing electronics are integrated on the same silicon substrate. The A17501 is capable of providing digital information that is representative of the mechanical features of a rotating target. Fig- ure 5 shows the automatic translation of the mechanical profile to the digital output signal. No additional optimization is needed, and minimum processing circuitry is required. This ease of use reduces design time and incremental assembly costs for most applications. BOP BOP BOP BRP BRP Device Orientation to Target IC (Pin 4 Side)(Pin 1 Side) Right Channel Element Pitch Left Channel Element Pitch Package Case Branded Face Target Magnetic Profile Mechanical Position (Target moves past device pin 4 to pin 1) S NN Target (Radial Ring Magnet) This pole sensed earlier This pole sensed later (Bottom View of Package Case) Channel Element Pitch Left Channel Speed Right Channel Speed Left Channel Right Channel E3E2E1 N IC Internal Differential Signals, BDIFF Output Option: Speed Output Protocol Figure 5: Magnetic Profile and Switch Points (BOP = 70%, BRP = 30%) Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Threshold Algorithms The A17501 contains selectable algorithms for determining when to produce an output transition from the magnetic input signal. For all options, a threshold is set within the sensor IC that triggers the output transition when crossed by the digitized magnetic signals (switch point). Dynamic Threshold With the A17501 programmed for the Dynamic Threshold option, each switch point is calculated from information learned from the previous target feature. This algorithm allows for robust tracking to produce accurate output transitions for inconsistent magnetic input signals (offset drift, amplitude changes, etc.). After power-on, the magnetic input signal is tracked to find the peaks of the signal. After each new peak is found, the switch points are updated based on a percentage of the previous two peaks. Fixed Threshold With the A17501 programmed for the Fixed Threshold option, an absolute threshold stored in memory is used to set the switch point for both the operate point and release point. This algorithm allows for accurate output transitions immediately after power-on for consistent magnetic input signals without the need to “learn” the signal. The threshold stored in memory and loaded during power- on contains threshold levels over temperature to allow for offset drift adjustment of the magnetic input signal over temperature. The A17501 sensor IC contains a temperature sensor used continu- ously to adjust the switch point over temperature as needed by the application. The fixed thresholds stored in memory can be pre-programmed for unique switch points over temperature for each application. Additionally, the A17501 can find and set the threshold for each installation over temperature during end-of-line calibration. If during the application the magnetic input signal offset does not match the programmed threshold stored in memory (due to inac- curate programming, mechanical shift, etc.), the A17501 identifies the threshold as “out of range”, calculates the threshold for the current temperature, and updates the threshold to produce correct output transitions. After the update, algorithms use the current temperature to recharacterize the threshold over the operational temperature range. This prevents the update from overcompensat- ing the threshold at a distant temperature relative to the update temperature. After the updated threshold is confirmed to be within the magnetic input signal’s switch point range over several target features, the updated threshold is stored into memory such that it can be used for subsequent power-on cycles. Figure 6: Dynamic Threshold Option Switch Point Algorithm (BOP = 70%, BRP = 30%) Figure 7: Fixed Threshold Option Switch Point Algorithm Speed Output Protocol BDIFF Ring Magnet S N S S S SN N N Speed Output Protocol BDIFF Ring Magnet S N S S S SN N N Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Hybrid Threshold With the A17501 programmed for the Hybrid Threshold option, the threshold is determined from the Fixed Threshold option at startup, then transitions to the Dynamic Threshold option after tracking signals have correctly acquired the magnetic input signals. This algorithm allows for both accurate output transi- tions immediately following power-on for consistent magnetic input signals as well as robust tracking to produce accurate output transitions of inconsistent magnetic input signals (offset drift, amplitude changes, etc.). Once the tracking signals have identified consistent peak values from the magnetic input signal, the algorithm will transition from using the fixed threshold switch point to using the dynamic thresh- old switch points. This transition occurs only when the magnetic input signal is near a maximum or minimum value, such that “double-switching” on the transition can be avoided. While the majority of the power-on will use the Dynamic Thresh- old option for robust signal tracking, the A17501 will continue to monitor the fixed threshold for comparison to the fixed threshold stored in memory. Should the fixed threshold require an update, the A17501 will update and write the new threshold to memory for use in subsequent power-on cycles. Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Manchester, NH 03103-3353 U.S.A. the A17501 to be programmed to application-level needs. Figure 8. These protocols can be programmed for either output used to determine the output transitions. reverse rotation (tw(FWD) and tw(REV)).

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Figure 9: Fault Detection Mode Disabled Output Figure 10: Fault Detection Mode Enabled Output Fault Detection Mode The A17501 allows for the output to transition between one of two sets of values. With Fault Detection mode disabled, the output will transition between approximately 0% and 100% of VPULLUP. With Fault Detection mode disabled, the output transi- tions between approximately 20% and 80% of VPULLUP. At the beginning of power-on, the A17501 outputs initialize to the VPULLUP level. With Fault Detection mode enabled, the output levels transition from VPULLUP to VHIGH before the end of power- on. After power-on, the output transitions as determined by the programmed algorithm and output protocol between VOUT(HIGH) and VOUT(LOW). Enabling Fault Detection mode allows for additional communica- tion for cases of open wire or short circuit, as well as allowing for the A17501 to communicate a fault detected from the internal diagnostics. For a typical application load circuit, these cases can be detected by observing either OUTA or OUTB transition to approximately 0 V or VPULLUP after tPO. VHIGH = VPULLUP VLOW tPO VPULLUP 0 V tPO VHIGH VLOW Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Fault Voltage The A17501 communicates a fault condition by configuring either output to hold within one of three VFAULT ranges (high, mid, and low) for greater than 1 millisecond. Normal operation allows for output transitions to occur over the VFAULT(MID) range; as such, it is necessary to ignore fast transients for less than 1 millisecond through this range. For internal diagnostics that trigger fault conditions (force the output to go to VFAULT), both outputs will go to the VFAULT(HIGH) range. As there may exist internal or external faults that cause either or both output pins to hold a VFAULT(MID) or VFAULT(LOW) level, these fault ranges should also be monitored. Examples of these fault conditions could be a short circuit of the output to ground, forcing the output to VFAULT(LOW), or a fault in the IC output controller that forces the output to VFAULT(MID). See Figure 11, Figure 12, and Figure 13 for examples of the out- put communicating a fault condition. Figure 11: Assumed Fault Example: High Fault Figure 12: Assumed Fault Example: Mid Fault Figure 13: Assumed Fault Example: Low Fault VFAULT(HIGH,min) VFAULT(MID,max) VFAULT(MID,min) VFAULT(MID,min) >1 ms Normal Operaon Assumed Fault VFAULT(HIGH,min) VFAULT(MID,max) VFAULT(MID,min) VFAULT(MID,min) >1 ms Normal Operaon Assumed Fault VFAULT(HIGH,min) VFAULT(MID,max) VFAULT(MID,min) VFAULT(MID,min) >1 ms Normal Operaon Assumed Fault Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com DEVICE FEATURES Undervoltage Lockout When supply voltage falls below the Undervoltage Lockout volt- age (VCC(UV)), the A17501 enters Reset, where the output state returns to the Power-On State (POS) until sufficient VCC is sup- plied. This feature prevents false signals, caused by undervoltage conditions, from propagating to the output of the sensor IC. Power Supply Protection The A17501 contains an on-chip regulator and can operate over a wide VCC range. For applications that need to operate from an unregulated power supply, transient protection must be added externally. For applications using a regulated line, EMI/RFI pro- tection is recommended. Contact Allegro for more information about circuitry to address EMC requirement compliance. Refer to the Typical Application Circuit section. Startup Hysteresis With a Power-On and a target held at zero-speed (fOP ≈ 0 Hz), noise and/or vibration can produce magnetic input signals. Startup hysteresis prevents peak tracking and switch point setting at startup immediately following power-on. This occurs until the sensed differential magnetic signal has moved sufficiently to satisfy the hysteresis band for signal tracking. This feature helps to ensure optimal self-calibration of the magnetic signals by rejecting electrical noise and low-amplitude target vibrations during startup and ensures that calibration occurs on actual target features. Small Signal Lockout When BDIFF(pk-pk) falls below specification, the internal logic of the sensor IC will indicate a reduced signal, as measured in an excessive air gap or a vibration condition. Small Signal Lockout will hold the output state at the level when BDIFF(pk-pk) was last in-specification. Once BDIFF(pk-pk) returns to an in-specification value, the output state is released to transition as expected during normal operation. When direction information is not explicitly defined by the selected output protocol, Small Signal Lockout is controlled independently for each channel. For example, Left Channel Speed + Right Channel Speed output protocol will allow for one channel to continue switching while the other is in lock- out. When direction information is explicitly communicated, for example XOR + Direction output protocol, Small Signal Lockout will occur when either channel’s BDIFF(pk-pk) falls below specifi- cation. Vibration Robust Signal Tracking During vibration events, the magnetic input signals can produce oscillations with a sufficient amplitude for the peak tracking algorithms to bound in and produce a non-ideal peak-to-peak. When the A17501 detects a direction change, inward bounding of the peak tracking signals is prevented. This prevents cases of erroneous output transitions from switch points being incorrectly set from vibration signals. Additionally, this allows for immediate acquisition of the magnetic input signals once real target rotation resumes following a vibration event. Signature Region Robust Signal Tracking Signature teeth (characterized by an extra target tooth and/or valley) can produce significant variations of the magnetic input signals. The bounded updating of the tracking signals prevent overcompensation for these signature variations to provide robust and accurate switch points for the signature region, as well as the features about the signature region. Temperature Drift Robust Signal Tracking As temperature changes can impact both the amplitude and offset of the magnetic signal, a full-range ADC, advanced algorithms, temperature compensation, watchdog timers, and an internal tem- perature sensor ensure robust signal tracking over temperature. To compensate for amplitude changes over temperature, tempera- ture compensated gain is first applied to normalize the amplitude over temperature. The full-range ADC and peak tracking algo- rithms track and acquire the signal to accurately set the switch points. To compensate for offset changes over temperature, two algo- rithms are implemented to ensure the signal tracking accurately follows and updates the switch points to follow the offset. With nominal target rotation, peak-tracking algorithms automatically follow and update the switch points over offset drift. With no target rotation (stopped condition), a watchdog timer is imple- mented which adjust the algorithms to track together, allowing for preservation of the correct signal peak-to-peak and switch points once rotation resumes. With the Fixed Threshold algorithm option selected, algorithms are implemented for continuous monitoring and updating of the fixed threshold over temperature to follow the offset drift of the system. This compensation is implemented for each channel independently to provide robust tracking of both signal channels over temperature. Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Diagnostics and Fault Reporting The A17501 contains diagnostics monitors of analog and digital circuits of the IC. These continuously monitor and report if any defect, calculation error, or invalid input stimulus is found. If a diagnostic monitor fires, the outputs of the A17501 will transi- tion to a VFAULT level. For all faults, the outputs will remain at the VFAULT level for enough time to allow the system controller to monitor that a fault has occurred. For some diagnostics, it is possible to clear the fault with a reset of the internal controller of the sensor IC. If any of those diagnostic monitors triggers the fault event, the A17501 will automatically perform a reset of the internal controller after the output is held VFAULT for enough time to allow the system controller to monitor the fault event. For diagnostics and fault reporting to perform correctly, proper programming and adherence to the specifications and assump- tions stated in this datasheet, the A17501 Safety Manual, and any other addendum, corrigendum, and application note that applies to the A17501. For more information on diagnostics and fault reporting, see the A17501 Safety Manual. Recalibration Under large amplitude vibration conditions at startup, the peak- to-peak and phase relationship of the magnetic input signals can meet the conditions to calibrate. Once normal rotation resumes, the actual signal amplitudes can be much larger than the peak signals acquired during calibration. Rather than wait several TCYCLE events for the peak signal to be tracked to actual levels, the A17501 will detect the difference and recalibrate on the new signal. Recalibration allows for fast and robust correction from cases of calibration on vibration events. Pulse Collision Prevention In cases of “high-speed” vibration, output transitions can occur at very high frequencies, to prevent pulse collision (truncation of the pulse width), the A17501 will prevent output transitions until the current output pulse transition is complete to ensure the system controller can accurately interpret the output signal. This feature is only implemented when a pulse protocol option is selected. High Configurability The A17501 contains programmable parameters, as shown in the Selection Guide, that can be configured to provide application- level optimization. Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com The device must be operated below the maximum junction tem- perature 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 appli- cation. 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 sum- marizing 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 a rela- tively 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 or PD), can be estimated. The following formulas represent the fundamental relationships used to estimate TJ, at PD. PD = VIN × IIN (1) ΔT = PD × RθJA (2) T J = TA + ΔT (3) For example, given common conditions such as: TA= 25°C, VCC = 12 V, ICC(avg) = 8.5 mA, and RθJA = 177°C/W, then: PD = VCC × ICC(avg) = 12 V × 8.5 mA = 102 mW ΔT = PD × RθJA = 102 mW × 177°C/W = 18.1°C A worst-case estimate, PD(max), represents the maximum allow- able power level (VCC(max), ICC(max)), without exceeding TJ(max), at a selected RθJA and TA. For example, calculating reliability of VCC given observed worst- case ratings, specifically: TA = 160°C, RθJA = 177°C/W, TJ(max) = 175°C, VCC(max) = 24 V , and ICC(max) = 15 mA. Calculation of the maximum allowable power, PD(max), can be done by first inverting equation 3 and calculating the maximum allowable increase to TJ: ΔTmax = TJ(max) – TA = 175 °C – 160 °C = 15 °C Then, maximum allowable power can be calculated by: PD(max) = ΔTmax ÷ RθJA = 15°C ÷ 177°C/W = 84.7 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) ÷ ICC(max) = 84.7 mW ÷ 15 mA = 5.65 V The results indicate that, at TA, the application and A17501 can dissipate adequate amounts of heat at voltages less than or equal to VCC(est). Compare VCC(est) to VCC(max). If VCC(est) ≤ VCC(max), then reli- able 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. POWER DERATING Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Figure 14: Package K, 4-Pin SIP 2 431

0.84 REF

1.27 NOM

2.16 MAX 45° 45° D Active Area Depth, 0.42 mm D B Gate and tie bar burr area A B C Dambar removal protrusion (8×) A D Standard Branding Reference View Line 1, 2 = 4 characters Line 1: Part Number Line 2: 4-digit Date Code Mold Ejector Pin Indent Branded Face Date Code XXXX 5.21 +0.08 –0.05 0.38 +0.06 –0.03 3.43 +0.08 –0.05 0.41 +0.07 –0.05 14.73 ±0.51 1.55 ±0.05 Branding scale and appearance at supplier discretion Hall elements (E1, E2, and E3); not to scaleEE E1 E3 E E 1.32 1.751.75 E For Reference Only – Not for Tooling Use (Reference DWG-0000395) Dimensions in millimeters – NOT TO SCALE Dimensions exclusive of moldﬂ ash, gate burrs, and dambar protrusions Exact case and lead conﬁguration at supplier discretion within limits shown PACKAGE OUTLINE DRAWING Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Dual Output Differential Speed and Direction Sensor ICA17501 Allegro MicroSystems Manchester, NH 03103-3353 U.S.A. www.allegromicro.com

Revision History

– March 19, 2020 Initial release For the latest version of this document, visit our website: www.allegromicro.com Copyright 2020, 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. Advance Information Datasheet Subject to Change Without Notice March 19, 2020

Summary

Dual Output Differential Speed and Direction Sensor IC

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