ATS344

ATS344 ALLEGRO | Alldatasheet

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Analog Subsystem Output Stage Magnetic Signal Hall Elements Analog Ampliﬁcation Stage Sensitivity and Fine Offset Adjustment Output Polarity Clamps Digital Signal Processing 12-bit

DESCRIPTION

The ATS344 device is a high-precision, back-biased programmable Hall-effect linear sensor integrated circuit (IC) with a conf igurable current-mode pulse-width-modulated output, for both automotive and non-automotive applications. Integrated within the ATS344 are two Hall-effect sensing elements, signal processing circuitry, and a rare-earth magnetic pellet. The magnetic pellet provides a common-mode magnetic bias while the outputs of the two sensing elements are subtracted, amplified, and processed to produce an output proportional to the differential magnetic input signal. The differential magnetic input signal is typically produced from influence of a ferromagnetic target. The ATS344 is well-suited for applications that require axial position sensing of a rotating target. The signal path of the ATS344 provides flexibility through external programming that allows the generation of an accurate, and customized output response from a ferromagnetic target perturbation. The ATS344 provides up to 10 bits of resolution. This part is calibrated at the factory to ensure the most stable response over specified conditions. The BiCMOS monolithic integrated circuit incorporates two Hall sensor elements and precision temperature-compensating circuitry to reduce the intrinsic sensitivity and offset drift or mismatch of the differential Hall elements. The amplif ication and analog-to-digital conversion path is designed to ensure optimal channel matching through the use of proprietary dynamic offset cancellation circuits, and advanced active stress compensation to reduce lifetime drift. ATS344S-DS, Rev. 1 MCO-0000355 FEATURES AND BENEFITS

Magnetic sensor IC with integrated rare-earth pellet
Two-wire current mode PWM (pulse-width modulation) output
Customer-programmable position range selection and offset, bandwidth, output clamps, and temperature compensation
Sensitivity temperature coeff icient and offset drift preset at Allegro
Temperature-stable, mechanical stress immune, and low noise device output via proprietary active stress compensation and four-phase chopper stabilization design techniques
Wide ambient temperature range: –40°C to 150°C
Operates with 3.75 to 9.5 V supply voltage
Differential linear signal processing
AEC-Q100 qualified High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet Package ATS344 Figure 1: ATS344 Signal Processing Path. Functions with programmable parameters indicated by double-headed arrows. PACKAGE: 3-pin SIP (suff ix SP) Not to scale August 8, 2018 Continued on next page...

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A. www.allegromicro.com ABSOLUTE MAXIMUM RATINGS Characteristic Symbol Notes Rating Unit Forward Supply Voltage VCC 20 V Reverse Supply Voltage VRCC –20 V Forward Supply Current ICC 30 mA Reverse Supply Current IRCC –30 mA Operating Ambient Temperature TA L temperature range –40 to 150 °C Maximum Junction Temperature TJ(max) 165 °C Storage Temperature Tstg –65 to 165 °C RoHS COMPLIANT SELECTION GUIDE Part Number Package Packing [1] Leadframe Plating ATS344LSPTN-T 3-pin SIP 13-inch reel 100% matte tin [1] Contact Allegro™ for additional packing options THERMAL CHARACTERISTICS: May require derating at maximum conditions; see application information Characteristic Symbol Test Conditions [2] Value Units Package Thermal Resistance RθJA Single-sided PCB, copper limited to solder pads, 2 pins (center pin removed) 159 °C/W Single-sided PCB, copper limited to solder pads, 3 pins 146 °C/W [2] Additional information is available on the Allegro website. With on-board EEPROM and advanced signal processing functions, the ATS344 provides an unmatched level of customer reprogrammable options for characteristics such as gain and offset, bandwidth, and output clamps. In addition, the device supports separate hot and cold temperature compensation. The ATS344 in the 3-pin SIP package (SP suffix) complies with the requirements of EU Directive 2002/95/EC (RoHS) and 2011/65/EU (RoHS II), amended by 2015/863/EU, on the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment. The package contains an integrated SmCo rare-earth pellet. DESCRIPTION (continued) Table of Contents EEPROM Customer-Programmable Parameter Reference ... 26

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Driver Communications Hall Elements Bandwidth Select Clock Generator Serial Decode Charge Pump Serial Interface Temperature Sensor Temperature Compensation Precision Reference ADC ADC Analog Regulator Digital Regulator Analog Front End Digital Subsystem Master Control EEPROM Control POR GND EEPROM HV Pulse Anti-Alias Filter A/D UV/OV Detection VCC ATS344 Output Polarity Clamp PW M Digital Sensitivity and Offset Trim Scan/ IDDQ 10 nF CBYPASS Pinout Diagram FUNCTIONAL BLOCK DIAGRAM Terminal List Table Number Name Function

1 VCC Input power supply and current mode PWM output

2 Test Pin used for production testing at Allegro

3 GND Device ground

PINOUT DIAGRAM AND TERMINAL LIST TABLE

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com ELECTRICAL CHARACTERISTICS: Valid through full operating temperature range, TA , and supply voltage, VCC , CBYPASS = 10 nF, unless otherwise specif ied Characteristics Symbol Test Conditions Min. Typ. Max. Unit GENERAL ELECTRICAL CHARACTERISTICS Supply Voltage [1] VCC 3.75 – 9.5 V Supply Current ICC(LOW) 6 – 10 mA ICC(HIGH) 13.6 – 16 mA ICC(HYS) 5.2 – 6.5 mA Reverse Supply Current IRCC VRCC = –20 V, TA = 25°C –8 – – mA Slew Rate [2] SL Refer to the application circuit in Figure 7 7 16 – mA/µs Supply Zener Clamp Voltage VZSUPPLY ICC = ICC(max) + 3 mA, TA = 25°C 20 – – V Hall Chopping Frequency fC TA = 25°C – 128 – kHz Undervoltage Detection [3] VCC(UV)LOW 3.4 – – V VCC(UV)HIGH – – 3.7 V Overvoltage Detection [3] VCC(OV)LOW 10.5 – – V VCC(OV)HIGH – – 13 V Output PWM Frequency fPWM EEPROM FPWM_DC code 3 850 1000 1150 Hz Integrated Capacitor CBYPASS – 10 – nF OUTPUT ELECTRICAL CHARACTERISTICS PWM Resolution ResPWM – 12 – bits Power-On Time [4][5] tPO BW setting = 500 Hz (EEPROM F3DB_DC = 4) – 3 – ms Signal Path Propagation Delay [4][5] tSDLY BW setting = 500 Hz (EEPROM F3DB_DC = 4) – 3 – ms Full Scale Output Range FSO – – 96 %DC [1] Supply Voltage is the potential measured between the VCC and GND pins. [2] Determined from design and lab characterization on a limited number of samples; not tested in production. [3] Refer to section on Protection Features for more information on Undervoltage and Overvoltage Detection. [4] Determined from design and lab characterization on a limited number of samples; not tested in production. [5] See Def initions of Terms section.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com MAGNETIC CHARACTERISTICS: Valid at TA = 25°C and VCC = 5 V , unless otherwise specif ied Characteristics Symbol Test Conditions Min. Typ. Max. Unit [1] INITIAL DEVICE VALUES (Before Customer Programming) Effective Resolution Reseff Reference Target at maximum air gap with F3DB_DC setting = 500 Hz – 9 – bits Input Signal Range BSIG Differential magnetic input signal –340 – 340 G Initial Sensitivity Sensinit SENSDC = 0x0 [2] – 0.404 – %FSO/G Initial Quiescent Output QOUTinit Infinite air gap – 50 – %FSO Initial Output Clamp OUTCLP(H)init 97.7 98 98.3 %DC OUTCLP(L)init 1.7 2 2.3 %DC Initial Sensitivity Drift Through Temperature Range [3] DSensinit TA = –40°C to 150°C –4 0 +4 % Initial Offset Output Drift Through Temperature Range [3] DOUT(Q)init TA = –40°C to 150°C – ±6 – G [1] FSO means Full Scale Output. See Def initions of Terms section. [2] This corresponds to a sensitivity multiplier of “4” according to the table “SENSDC - values” on page 32. [3] Initial Offset and Sensitivity drifts through temperature range may vary with influences from the application Target.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Continued on the next page… PROGRAMMABLE CHARACTERISTICS: Valid through full operating temperature range, TA , and supply voltage, VCC , CBYPASS = 10 nF, unless otherwise specif ied Characteristics Symbol Test Conditions Min. Typ. Max. Unit [1] INTERNAL BANDWIDTH PROGRAMMING Bandwidth Programming Bits Bits(BW) – 3 – bit Bandwidth Programming Range [2] BW TA = 25°C; for programming values, see F3DB_DC in EEPROM Structure section 250 – 4000 Hz Bandwidth Post-Programming Tolerance ∆BW TA = 25°C, measured as a percentage of BW – ±5 – % F INE QUIESCENT OUTPUT ADJUSTMENT F ine Quiescent Output Adjustment Bits QVODC – 12 – bit F ine Quiescent Output Adjustment Range QOUT_FINE TA = 25°C, BDIFF = 0 G –50 – 49.98 %FSO F ine Quiescent Output Adjustment Step SizeStepQOUT_FINE TA = 25°C, BDIFF = 0 G – 0.0244 – %FSO OUTPUT SENSITIVITY Output Sensitivity Programming Range [3] SENSMULT TA = 25°C 0 – 8 – Sensitivity Programming Bits [4] SENSDC – 12 – bit Sensitivity Programming Step Size StepSENS_OUT TA = 25°C – 2–11 – – Output Polarity Bit OUTPUT_ INVERT – 1 – bit [1] FSO means Full Scale Output. See Def initions of Terms section. [2] Determined from design; not tested in production. [3] The Initial Sensitivity is adjustable by the SENSDC parameter. When reducing the initial Sensitivity check the input signal is within the range specified by BSIG. [4] Sensitivity programming parameter SENSDC is a multiplier applied to the initial Sensitivity with step size defined by StepSENS_OUT parameter. Refer to the Programmable Parameter Reference section for more information.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com PROGRAMMABLE CHARACTERISTICS (continued): Valid through full operating temperature range, TA , and supply volt- age, VCC , CBYPASS = 10 nF, unless otherwise specif ied Characteristics Symbol Test Conditions Min. Typ. Max. Unit TEMPERATURE COMPENSATION (TC) FOR BACK-BIASED DEVICES 1st Order Sensitivity TC Programming Bits TC1_SENS_CLD, TC1_SENS_HOT – 8 – bits 1st Order Sensitivity TC Programming Range TC1SENS –0.0976 – 0.291 %/°C 1st Order Sensitivity TC Programming Step Size StepTC1SENS – 1.526 – m%/°C 2nd Order Sensitivity TC Programming Bits TC2_SENS_CLD, TC2_SENS_HOT – 9 – bits 2nd Order Sensitivity TC Programming Range TC2SENS –1.526 – 1.52 %/(°C)2 2nd Order Sensitivity TC Programming Step Size StepTC2SENS – 0.00596 – m%/(°C)2 OUTPUT CLAMPING RANGE 1st Order Magnetic Offset TC Programming Bits DBOFFDC – 8 – bits 1st Order Magnetic Offset TC Programming Range TC1_OFFSET [1] Sens = 21 LSB/G, SENSDC = 0 –0.867 – 0.867 G 1st Order Magnetic Offset TC Programming Step Size StepTC1_OFFSET Sens = 21 LSB/G, SENSDC = 0 – ±0.0068 – G Clamp Programming Bits CLAMP_HIGH – 11 – bits CLAMP_LOW – 11 – bits Output Clamp Programming Range OUTCLP(H) TA = 25°C 51 – 100 %FSO OUTCLP(L) TA = 25°C 0 – 49 %FSO Clamp Programming Step Size StepCLP(H) TA = 25°C – 0.0239 – %FSO StepCLP(L) TA = 25°C – 0.0239 – %FSO ACCURACY (AFTER CUSTOMER PROGRAMMING) Sensitivity Drift Due to Package Hysteresis ∆SensPKG Variation on f inal programmed Sensitivity value; measured at TA = 25°C after temperature cycling – < ±1.5 – % Linearity Error [2] ERRLIN Deviation from an ideal straight line sensor response at maximum air gap –2 – 2 %FSO Offset Drift Over Lifetime [3] ERROUT AEC-Q100 grade 0 qualification –15 – 30 G Temperature cycle profile: –40°C to 130°C for 9 cycles, –40°C to 150°C for 1 cycle; dwell time of 15 minutes at min. and max. temperature; ramp rate of 7.8°C/minute from –40°C to 20°C; total of 1000 cycles –12 – 12 G Offset Drift Over Supply Voltage Range [4] ERRVCC 0 – 4 G [1] TC1_OFFSET range can vary by ±10% with the initial factory settings. [2] Does not include nonlinearity of the target shape. Determined from design; not tested in production. [3] Offset drift from the custom temperature cycles characterized on product of same family using same package, same lead frame, and same die size with identical Hall location. [4] Voltage calculated as QOUT at VCC(max) – QOUT at VCC(min).

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com This reference target is an example for linear displacement measurement in conjunction with the ATS344. The target displacement range and the air gap is determined by the size of the “V-groove” and the material. The groove can be machined on any ferrous part, even on rotating shafts that have an axial movement. Please contact Allegro directly for support on target shape selection; Allegro can provide examples of potential target solutions and in certain situations may provide custom target design support. X (mm) Z (mm) X (mm) Z (mm) –5.25 –3.5 –1.75 5.25 3.5 1.75 –0.65 –1.43 –2.35 –0.65 –1.43 –2.35 –3.5 6.5 mm Centerline Displacement (Side View) ATS344 Placement (Detail View) ATS344 (Side View) Position 1 Position 1 Position 2 Position 2 Position 3 Position 3 (Top/Bottom View) 7.65 mm mm mm mm mm Z = Air Gap X = Centerline Displacement Z = Air Gap mm Dual Hall elements Dual Hall elements REFERENCE TARGET CHARACTERISTICS Figure 2: Reference Target Characteristics Reference target material: 1018 CRS mild steel with nickel plating (electroless plating thickness 0.75-1.28 µm)

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com FUNCTIONAL DESCRIPTION This section provides descriptions of the operating features and subsystems of the ATS344. For more information on specif ic terms, refer to the Def initions of Terms section. Tables of EEPROM parameter values are provided in the EEPROM Struc- ture section and EEPROM Customer-Programmable Parameter Reference. Digital Signal Processing TEMPERATURE COMPENSATION The magnetic properties of materials can be affected by changes in temperature, even within the rated ambient operating tempera- ture range, T A . Changes in the differential magnetic input signal due to temperature variation causes a proportional change in the device output. The ATS344 features integrated digital tempera- ture compensation (TC) circuitry that is programmable to reduce influences of all reproducible externally induced variations. Tem- perature coefficients for Sensitivity and Offset are programmable using the corresponding EEPROM parameters. The ATS344 uses 1st order Magnetic Offset TC to compensate for output offset drift across the ambient temperature range (see Figure 5). The programmable parameter, DBOFFDC, is used to adjust the Magnetic Offset TC. For more information on the programmable parameter, DBOFFDC, refer to the EEPROM Customer-Programmable Parameter Reference section. In addition to the Magnetic Offset TC compensation, the ATS344 also contains features to compensate Sensitivity for variations of the differential magnetic input signal with temperature. This is accomplished with segmented 1st and 2nd order Sensitivity TC that dynamically adjusts the Sensitivity. There are two program- mable Sensitivity TC segments: temperatures above 25°C, Hot, and temperatures below 25°C, Cold. Each segment is indepen- dently programmable with 1st and 2nd order coefficients. See Table 1 for a list of the programmable parameters and Figure 6 for illustrations of the Sensitivity TC. Refer to the EEPROM Customer-Programmable Parameter Reference section for more information. Output Polarity Sensitivity Multiplier /Fine Offset Adjustment Figure 4: Signal Path for Digital Subsystem DBOFFDC Min. Setting DBOFFDC Max. SettingDOUT(Q)init TA 25°C TC1_OFFSET QOUT Figure 5: The Magnetic Offset Temperature Compensation Coefficient, TC1_OFFSET TC1_SENS_HOT Min. Setting TC1_SENS_CLD Min. Setting TC1_SENS_HOT Max. Setting TC1_SENS_CLD Max. Setting ΔSENSinit Sensitivity TA TC1SENS TA Sensitivity 25°C TC2SENS 25°C ΔSENSinit TC2_SENS_HOT Min. Setting TC2_SENS_CLD Min. Setting TC2_SENS_HOT Max. Setting TC2_SENS_CLD Max. Setting Table 1: Sensitivity Temperature Compensation Parameters TA Range < 25°C > 25°C 1st Order TC1_SENS_CLD TC1_SENS_HOT 2nd Order TC2_SENS_CLD TC2_SENS_HOT Figure 6: Sensitivity TC Function: (upper) first order, (lower) second order

Manchester, NH 03103-3353 U.S.A. in Figure 4. The value of QVODC is a percentage of the FSO. It is programmable to add or subtract as much as 50% of FSO. Reference section for more information on parameter QVODC. in equation 3. This value is prior to the clamps. defined with a SENS_MULT default of 4. polarity with respect to the sensed magnetic response polarity. parameter to 1 inverts the output value. Figure 4. The ATS344 output clamps are initially set to 0% and 100% of FSO, for low and high output clamp respectively.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Protection Features Supply voltage detection and clamping features protect the ATS344 internal circuitry and prevent spurious output when sup- ply voltage is out of specif ication. PREPROGRAMMED DEFAULT VALUES Default values prevent system failures due to communication errors during real time customer reprogramming of EEPROM. The default values also can be used as defaults for normal opera- tion, reducing the initial customer programming requirements. UNDERVOLTAGE AND OVERVOLTAGE DETECTION The ATS344 contains circuitry to detect a condition when the supply voltage drops below or exceeds specified operating limits. Hysteresis is designed into the circuits to prevent chattering around the threshold. This hysteresis is defined by V CC(UV)HIGH – VCC(UV)LOW for undervoltage detection and VCC(OV)HIGH – VCC(OV)LOW for overvoltage detection. As an example, initially VCC is within the normal operating range. If VCC drops below VCC(UV)LOW, the output duty cycle is forced to a 100% duty cycle, with the output at approximately ICC(HIGH). Note, as VCC further reduces below the specified operating range, the ICC(HIGH) level reduces, and the there is no PWM output signal transmitted. When VCC returns above VCC(UV)HIGH, the output returns to its normal operating state. The output will not respond with normal data until a delay of t PO after an undervoltage event. The ATS344 contains circuitry to detect a condition when the supply voltage rises above the specified operating limit. As an example, initially V CC is within the normal operating range. If VCC rises above VCC(OV)HIGH, the output duty cycle is forced to 0% duty cycle, with the output at approximately ICC(LOW). When VCC returns below VCC(OV)LOW, VOUT returns to its normal operating state. EEPROM FAULT DETECTION The ATS344 contains EEPROM with error checking and cor- rection, ECC. The ECC corrects for a single-bit EEPROM error without effecting device performance. The ECC also detects a dual-bit EEPROM error and triggers an internal fault signal that disables the output to 0% duty cycle, or I CC(LOW) state.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com The device contains an on-chip regulator and can operate across a wide VCC range. For devices that must operate from an unregu- lated power supply, transient protection must be added externally. For applications using a regulated line, EMI/RF i protection may still be required. Contact Allegro for information on the circuitry required for compliance with various EMC specif ications. Refer to Figure 7 for an example of a basic application circuit. Sense resistor minimum value is determined by the desired signal-to- noise ratio of the current interface, while its maximum value is determined by the supply voltage and the voltage drop across said resistor (headroom). Figure 7: Typical Application Circuit ATS344 Pin 1: VCC Current Modulator ICC Supply Voltage VDC Pin 3: GND RSENSE 62 □ Output Voltage Schmitt Trigger Pin 2 ﬂoating Integrated Capacitor CBYPASS 10 nF Typical Application

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com PROGRAMMING SERIAL INTERFACE The ATS344 incorporates a serial interface that allows an external controller to read and write registers in the ATS344 EEPROM and volatile memory. The ATS344 uses a point-to-point communica- tion protocol, based on Manchester encoding per G. E. Thomas (a rising edge indicates 0 and a falling edge indicates 1), with address and data transmitted MSB f irst. Commands are sent to the device via modulation of V CC (refer to VCC(OV)HIGH and VCC(OV)LOW thresholds); the device responds by modulation of ICC. Transaction Types Each transaction is initiated by a command from the controller; the ATS344 does not initiate any transactions. Two commands are recognized by the ATS344: Write and Read. There also is a spe- cial function Write command: Write Access Code. One response frame type is generated by the ATS344, Read Acknowledge. If the command is Read, the ATS344 responds by transmitting the requested data in a Read Acknowledge frame. If the command is any other type, the ATS344 does not acknowledge. As shown in Figure 8, The ATS344 receives all commands via the VCC pin. It responds to Read commands via the ICC. This implementation of Manchester encoding requires the communica- tion pulses to cross the overvoltage detection thresholds CC(OV)HIGH, VCC(OV)LOW). Writing the Access Code If the external controller intents to write or to read from the ATS344 memory during the current session, it must establish serial communication with the ATS344 by sending a Write com- mand including the Access Code within t ACC after powering up the ATS344. If this deadline is missed, all write and read access is disabled until the next power-up. Figure 8: Top-Level Programming Interface ATS344 GND V V I C C C C C C ECU Write/Read Command – Manchester Code Read Acknowledge – Manchester Code

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Reading from EEPROM A Read command with the register number is sent from the con- troller to the ATS344. The device responds with a Read Acknowl- edge frame. Output is automatically disabled after the Read com- mand from the controller is received and output is enabled after a Read Acknowledge command is sent. C1C0 C2 Input Data 1x0 1x1 0x2 1x3 = x3 + x + 1 Figure 9: CRC Calculation Error Checking The serial interface uses a cyclic redundancy check (CRC) for data-bit error checking (synchronization bits are ignored during the check). The CRC algorithm is based on the polynomial g(x) = x 3 + x + 1 and the calculation is represented graphically in Figure 9. The trailing 3 bits of a message frame comprise the CRC token. The CRC is initialized at 111.The trailing 3 bits of a message frame comprise the CRC token.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Serial Write to Volatile Memory The write sequence is initiated by pulsing VCC above the over- voltage detection threshold, which will cause disabling of the PWM output (ICC = ICC_LOW). Following this, Manchester data can be sent in on VCC. Once the write is complete, PWM output will start the next PWM frame. This is shown in Figure 10. VCC nominal operating level RX_IN PWM_OUT INTERFACE STATUS Manchester Data tt t t Internally gate Manchester RX Internally gate Manchester RXAllow sampling Manchester RX Overvoltage Detection Threshold High Level VCC(OV)HIGH Overvoltage Detection Threshold Low Level V CC(OV)LOW prgEN msgRX outEN gate Figure 10: Serial Write to Volatile Memory TIMING DIAGRAMS

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Serial Write to EEPROM The write sequence is initiated by pulsing VCC above the over- voltage detection threshold, which will cause disabling of the PWM output (ICC = ICC_LOW). Following this, Manchester data can be sent in on VCC. The EEPROM and charge pump con- trollers will then handle the write to EEPROM. Once the write VCC nominal operating level VCC Comparator PWM_OUT INTERFACE STATUS Manchester Data tt tt t Internally gate Manchester RX Internally gate Manchester RXAllow sampling Manchester RX prgEN msgRX write outEN gate Overvoltage Detection Threshold High Level VCC(OV)HIGH Overvoltage Detection Threshold Low Level V CC(OV)LOW Figure 11: Serial Write to EEPROM is complete, PWM output will start the next PWM frame. This is shown in Figure 11. The minimum waiting time after initiating communication is t gate. The maximum time is tmsgRX. Transmis- sion of Manchester code has to start within that time window.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Serial Read from EEPROM The write sequence is initiated by pulsing VCC above the over- voltage detection threshold, which will cause disabling of the PWM output (ICC = ICC_LOW). Following this, Manchester data can be sent in on VCC. Manchester data will be output on ICC. Once the read is complete (Manchester data transmitted), PWM output will start the next PWM frame. This is shown in Figure 12. VCC ICC nominal operating level VCC Comparator PWM_OUT INTERFACE STATUS Manchester Data Manchester Data tprgEN tmsgRX toutEN tmsgTX tgate Internally gate Manchester RX Internally gate Manchester RXAllow sampling Manchester RX Overvoltage Detection Threshold High Level VCC(OV)HIGH Overvoltage Detection Threshold Low Level V CC(OV)LOW Figure 12: Serial Read

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Serial Access Timeout Any attempt at a Manchester transaction has a timeout associated with the falling edge of the initial pulse on VCC and the start of Manchester data. If that timeout period expires, then PWM_ OUT_ENABLE will go high and PWM output will start the next PWM frame. This is shown in Figure 13. VCC ICC nominal operating level VCC Comparator PWM_OUT_ENABLE INTERFACE STATUS tt t t Internally gate Manchester RX Internally gate Manchester RXAllow sampling Manchester RX prgEN msgRX outEN gate Overvoltage Detection Threshold High Level V CC(OV)HIGH Overvoltage Detection Threshold Low Level V CC(OV)LOW Figure 13: Serial Access Timeout

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Table 2: Serial Interface Timing Parameters Characteristics Symbol Note Min. Typ. Max. Unit Access Code Timeout tACC Customer Access Code should be fully transmitted in less than tACC, measured from when VCC crosses VCC(OV_high). – – 70 ms Bit Rate Def ined by the input message bit rate sent from the external controller 4 – 100 kbps Bit Time Error errtbit Deviation for a single bit defined by Manchester encoding –11 – 11 % Time to Enable Programming t prgEn 55.6 – n/a µs Time Before Transmitting Manchester Data to Device tmsgRx 5.6 – 862 µs Time Before Device Will Listen to RX tgate 0.8 – 1.1 µs Time for Output to Start toutEn 0.05 – 0.1375 µs Time for EEPROM Write twrite – 25 – ms Time Before Device will Respond with Read Acknowledge tmsgTX 300 475 700 µs

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com The general format of a command message frame is shown in Figure 14: General Format for Serial Interface Commands. Note that, in the Manchester coding used, a bit value of 1 is indicated by a falling edge within the bit boundary, and a bit value of zero is indicated by a rising edge within the bit boundary. The bits are described in Table 3. Synchronize MSB MSB Manchester Code per G. E. Thomas Bit boundaries Memory Address Data CRC Read/Write 0 0 0/1 0/1 0/1 0/1 0/1 0/1 0 0 0 1 1 Figure 14: General Format for Serial Interface Commands Table 3: Serial Interface Command General Format Bits Parameter Name Values Description

2 Synchronization 00 Used to identify the beginning of a serial interface command

1 Read/Write

0 [As required] Write operation 1 [As required] Read operation

6 Address 0/1 [Read/Write] Register address (volatile memory or EEPROM)

30 Data 0/1 [As required]

3 CRC 0/1 Incorrect value indicates errors

The following command messages can be exchanged between the device and the external controller:

Read
Read Acknowledge
Write
Write Access Code For EEPROM address information, refer to the EEPROM struc- ture section. SERIAL INTERFACE MESSAGE STRUCTURE

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Table 4: Read Command Function Provides the address in ATS344 memory to be accessed to transmit the contents to the external controller in the next Read Acknowledge command. Syntax Sent by the external controller on the ATS344 VCC pin Related Commands Read Acknowledge Pulse Sequence Synchronize MSB Read/Write 001 Memory Address CRC Options Example Read Address 0x08 Read/Write = 1 Memory Address = 001000 CRC bits = 110 Table 5: Read Acknowledge Function Transmits to the external controller data retrieved from the ATS344 memory in response to the most recent read command. Syntax Sent by the ATS344 by ICC modulation. Sent after a Read command Related Commands Read Pulse Sequence Synchronize MSB Data (30 bits) CRC Options The 6 MSBs are EEPROM data error checking bits. Refer to the EEPROM structure section for more information Example –

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Table 6: Write Command Function Transmits to the ATS344 data prepared by the external controller Syntax Sent by the external controller on the ATS344 VCC pin. Related Commands Pulse Sequence Synchronize Memory Address Read/Write MSB MSB 0 0/1 0/10 0/1 0/1 Data (30 bits) CRC Options Example Table 7: Write Access Code Command Function Transmits the access code to the ATS344; data prepared by the external controller, but must match the internal 30-bit code in the ATS344 memory. Syntax Sent by the external controller on the ATS344 VCC pin. Sent within 70 ms of A1343 power-on and before any other command. Related Commands Pulse Sequence Synchronize Memory Address Read/Write MSB MSB 011 000 Data (30 bits) CRC 1000 00 1 0/1 0/1 0/1... Options Example Standard Customer Access Code: 0x2781_1F77 to address 0x24 Read/Write = 0 Memory Address = 100100 Data bits = 10 0111 1000 0001 0001 1111 0111 0111 CRC bits = 001

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com OUTPUT PROTOCOL The operating output of the ATS344 is a pulse-width modulated current output signal that transfers information proportionally to the applied magnetic input signal. PWM Output PWM involves using a current modulation where the state of the pulse is def ined by high or low current consumption. These levels are specif ied as I CC(LOW) and ICC(HIGH) in the Electrical Characteristics table. The duration at which the part is operating at I CC(LOW) or ICC(HIGH) is pulse-width modulated to achieve the output designated signal. The percentage of ICC(HIGH) versus the period duration designates the target position.

CALIBRATE_PWM parameter can be set to enable calibration of the output 50% duty cycle level at power-on. Target Deflection, BIN (mm) PWM Current Waveform (A) D1T D2T D4TD3TD0T D5T tpulse(5) tperiod D6T D7T D8T D(x) = tpulse(x) / tperiod D9T D10T CLAMP_HIGH CLAMP_LOW 2T 3T 4T 5T 6T 7T 8T 9T 10T 11T Time Figure 15: PWM outputs a duty-cycle-based waveform that can be read by the external controller as a cumulatively changing continuous current.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Programmable values are stored in an onboard EEPROM, including both volatile and non-volatile registers. Although it is separate from the digital subsystem, it is accessed by the digital subsystem EEPROM Controller module. Because EEPROM can be read by multiple devices, an arbiter controls access to EEPROM. In the case of simultaneous accesses to EEPROM, priority is assigned as follows: 1. Static Registers (highest) 2. Temperature Compensation 3. Linearization 4. Serial Interface (lowest) The EEPROM is organized as 30-bit-wide words, and by default each word has 24 data bits and 6 ECC (Error Checking and Cor- rection) check bits, stored as shown in Figure 16. Figure 16: EEPROM Word Bit Sequence; C# – Check Bit, D# – Data Bit EEPROM STRUCTURE 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 D9 D8 D7 D6 D5 D4 C4 D3 D2 D1 C3 D0 C2 C1 C0 EEPROM Bit 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 Contents D23 D22 D21 D20 D19 D18 D17 D16 D15 D14 D13 D12 D11 C5 D10 Table 8: EEPROM Register Map of Customer-Programmable Parameters Parameter Name Address Bits Description TC2DC_HOT 0x08 [23:15] 9 2nd order sensitivity TC, TA > 25°C TC2DC_CLD 0x08 [14:6] 9 2nd order sensitivity TC, TA < 25°C TC1DC_HOT 0x09 [23:16] 8 1st order sensitivity TC, TA > 25°C TC1DC_CLD 0x09 [15:8] 8 1st order sensitivity TC, TA < 25°C DBOFFDC 0x09 [7:0] 8 1st order magnetic offset drift SCRATCH_C_0 0x0A [23:12] 12 Customer scratch area 0 SENSDC 0x0A [11:0] 12 Sensitivity Unused 0x0B-0x19 {23:12] 12 Unused memory locations Reserved 0x1A [11:0] 12 Factory access only Unused 0x1B [23] 1 OUTPUT_INVERT 0x1B [22] 1 Invert output Unused 0x1B [21] 1 ID_C 0x1B [20:12] 9 Customer ID CLAMP_HIGH 0x1C [23:18] 6 Clamp upper bound CLAMP_LOW 0x1C [17:12] 6 Clamp lower bound F3DB_DC 0x1C [2:0] 3 F ilter bandwidth select SCRATCH_C_1 0x1D [23:12] 12 Customer scratch area 1 QVODC 0x1D [11:0] 12 Offset OUTDRV_CFG 0x1E [20:18] 3 OUTDRV_CFG Output driver rise, fall time or slew rate control setting CALIBRATE_PWM 0x1E [3] 1 Enable 50% duty cycle calibration at startup PWM_CFG 0x1E [2:0] 3 PWM conf iguration parameters SCRATCH_C_2 0x1F [23:0] 24 Customer scratch area 2 CLAMP_OUT [1] 0x29 [11:10] 2 Output of clamp block [1] Read only.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com EEPROM Customer-Programmable Parameter Reference Table 9: F3DB_DC: Address 0x1C, bits 2:0 Function F ilter Bandwidth Selects the f ilter bandwidth (3-dB frequency) for the digitized applied magnetic f ield signal, applied when passed to the digital system after analog front-end processing. This selection also sets the internal update rate. Syntax Quantity of bits: 3 Related Comments Values (typical) Code Bandwidth (Hz) Internal Update Rate (kHz) 2000 4000 2000 1000 500 250 Not recommended Not recommended Options – Examples – Table 10: CALIBRATE_PWM: Address 0x1E, bit 3 Function PWM Calibration When CALIBRATE_PWM is set to logic 1, the device outputs a 50% duty cycle PWM output for 800 ms after power on. Syntax Quantity of bits: 1 Related Commands PWM_MODE (see EEPROM Structure Section) Values 0: Disable calibration (Default) 1: Enable calibration Options Examples The 50% duty cycle output after power on can be used to synchronize or calibrate the PWM output reading with an external controller. Table 11: CLAMP_HIGH: Address 0x1C, bit 23:18 Function Clamp Upper Limit Sets the percentage of the upper half of the Full Scale Output signal passed through at the end of the Digital Signal Processing stage. Syntax Quantity of bits: 6 Related Commands CLAMP_LOW Values 0x0: Default (Maximum specif ied value, OUT CLP(H)) 0x3F: (Minimum specif ied value, OUTCLP(H)) Options The factory-programmed default, OUTCLP(H)init, is used if this parameter is not set. Examples

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Table 12: CLAMP_LOW: Address 0x1C, bit 17:12 Function Clamp Lower Limit Sets the percentage of the lower half of the Full Scale Output signal passed through at the end of the Digital Signal Processing stage. Syntax Quantity of bits: 6 Related Commands CLAMP_HIGH Values 0x0: Default (Minimum specif ied value, OUT CLP(L)) 0x3F: (Maximum specif ied value, OUTCLP(L)) Options The factory-programmed default, OUTCLP(L)init, is used if this parameter is not set. Examples Table 13: PWM_CFG: Address 0x1E, bits 2:0 Function PWM Carrier Frequency Sets the carrier frequency for PWM mode normal output (voltage response to applied magnetic f ield). Selected frequency determines maximum output resolution. Syntax Quantity of bits: 3 Related Comments Values (typical) Code PWM Frequency (kHz) Maximum Output Resolution (bits) 0.125 0.25 0.5 0.125 0.125 Options – Examples – Table 14: ID_C: Address 0x1B, bit 20:12 Function Customer Identif ication Number Available register for identifying the ATS344. Syntax Quantity of bits: 9 Related Commands SCRATCH_C Values Free-form Options Values do not affect device operation. Examples

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Table 15: OUTDRV_CFG: Address 0x1E, bit 20:18 Function Output Signal Conf iguration Sets conf iguration of the output signal slew-rate control. Sets the ramp rate on the gate of the output driver, thereby changing slew rate at the output. Syntax Quantity of bits: 3 Related Commands Values Options Code Typical Rise Time (ns) Typical Fall Time (ns) 0 323 331 1 327 389 2 327 389 3 354 560 4 327 389 5 354 560 6 354 560 7 478 761 Examples Table 16: OUTPUT_INVERT: Address 0x1B, bit 22 Function Output Polarity Inversion Inverts the polarity of the device output. Syntax Quantity of bits: 1 Related Commands Values 0:Positive output polarity. Left channel minus Right channel greater than zero. 1:Negative output polarity. Left channel minus Right channel less than zero. Options Examples

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Table 17: QVODC: Address 0x1D, bit 11:0 Function Quiescent Output (QVO) Adjusts the device normal output (digital response to applied magnetic f ield) to set the baseline output level: for a quiescent applied magnetic f ield (differential input f ield ≈ 0 G). Syntax Quantity of bits: 12 Code stored in two’s complement format Related Commands SENSDC Values Fine Offset Adjustment QOUT_FINE(max.) Initial (Default) QOUT_FINE(min.) 0 0x800 0xFFF QVODC Options Examples Table 18: SCRATCH_C_0: Address 0x0A, bits 23:12 SCRA TCH_C_1: Address 0x1D, bits 23:12 SCRA TCH_C_2: Address 0x1F, bits 23:0 Function Customer Scratchpad For optional customer use in storing values in the device. Syntax Quantity of bits: SCRATCH_C_0, 12 SCRATCH_C_1, 12 SCRATCH_C_2, 24 Related Commands IC Values Free-form f ield Options Values do not affect device operation Examples

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Table 19: DBOFFDC: Address 0x09, bits 7:0 Function 1st Order Magnetic Offset Temperature Compensation coeff icient See Temperature Compensation section for more details. Syntax Quantity of bits: 8 Code stored in two’s complement format. Related Commands TC1_SENS_CLD, TC1_SENS_HOT, TC2_SENS_CLD, TC2_SENS_HOT Values 1st Order Magnetic Offset Temperature Compensation Coefﬁcient G/ºCTC1_OFFSET(max) Initial (Default) TC1_OFFSET(min) 0 0x80 0xFF TC1_OFFSET Options Examples

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Table 20: TC1_SENS_CLD: Address 0x09, bits 15:8 TC1_SENS_HOT : Address 0x09, bits 23:16 Function 1st Order Magnetic Offset Temperature Compensation coeff icient See Temperature Compensation section for more details. Syntax Quantity of bits: 8 Code stored in shifted two’s complement format. Related Commands TC1_SENS_CLD, TC1_SENS_HOT, TC2_SENS_CLD, TC2_SENS_HOT Values 1st Order Sensitivity Temperature Compensation Coefﬁcient TC1SENS(max.) Initial (Default) TC1SENS(min.) 0 0xC0 0xFF TC1_SENS_HIT TC1_SENS_CLD Options Examples The factory-programmed default, ΔSensinit, is used if neither these parameters, nor the TC2_SENS_HOT, TC2_ SENS_CLD parameters, are set.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Table 22: SENSDC: Address 0x0A, bits 11:0 Function Customer Sensitivity Setting Syntax Quantity of bits: 12 Code stored in two’s complement format. Related Commands Values 8.0 0x800 0x FFF 4.0 SENSDC value SENSDC code SENS_MULT Options SENS_MULT values in the figure represent a Sensitivity multiplier relative to the initial Sensitivity, Sensinit, and are not absolute Sensitivity values. Examples Table 21: TC2_SENS_CLD: Address 0x08, bits 14:6 TC2_SENS_HOT : Address 0x08, bits 23:15 Function 2nd Order Sensitivity Temperature Coeff icient. Refer to Temperature Compensation section for more details. Two different parameters are set, one for increasing values relative to T A = 25°C, and the other for decreasing values, as follows: TC2_SENS_HOT: ΔTA (from 25°C) > 0 TC2_SENS_CLD: ΔTA (from 25°C) < 0 Syntax Quantity of bits: 9 Code stored in two’s complement format. Related Commands TC1_SENS_HOT, TC1_SENS_CLD Values 2nd Order Sensitivity Temperature Compensation Coefﬁcient TC2SENS(max) TC2SENS(min) TC2_SENS_HOT TC2_SENS_CLD Initial (Default) 0 0x100 0x1FF Options Examples The factory-programmed default, DSensinit, is used if neither these parameters, nor the TC1_SENS_HOT, TC1_ SENS_CLD parameters, are set.

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com General Programming PROGRAMMING RANGE The values of a programmable parameter that are within a central range bounded by the distributions of the values that could result from programming the minimum and maximum codes available for that parameter (see Figure 17). Because the endpoints of a programmable range have normal distributions, they are excluded from the range of values. The limits of the range are indicated by the minimum and maximum values in the Operating Character- istics table. For customer-programmable parameters, the typical default initial value lies within the programming range, and usu- ally serves as the reference point for setting value ranges. FULL-SCALE OUTPUT, FSO The available output range of the ATS344 is defined as the full scale output, FSO. The default FSO is region bound by OUT CLP(L)(min.) and OUTCLP(H)(max.). See Figure 18. DEFINITIONS OF TERMS X(min) X(max) Typical initial value after factory programming, Xinit(typ) Specified programming range parameter X values Parameter X values resulting from minimum programming code Parameter X values resulting from maximum programming code Figure 17: Def inition of a Programming Range General Programming Programming Range Full-Scale Output, FSO Timing Power-On Time, t PO Signal Response Time Quiescent F ield Response Baseline Figure 18: Full-Scale Output (FSO) Magnetic Field Response, BIN (G) 100 50.78 49.22 PWM (%FSO) B– B+ FSO Offset Output, QOUT Clamp Programming Range Device Response to Target Deflection Sensitivity, Sens Device Accuracy Quiescent Output Drift Through Temperature Range Sensitivity Drift Through Temperature Range

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet PackageATS344 Allegro MicroSystems, LLC Manchester, NH 03103-3353 U.S.A. www.allegromicro.com Timing POWER-ON-TIME, tPO The time required for device output to begin the transmission of the f irst valid duty cycle (PWM mode), after the power supply has reached its minimum specif ied operating voltage, V CC(min). When the supply is ramped to its operating voltage, the device requires a f inite time to power internal circuits before supplying a valid output value. SIGNAL RESPONSE TIME Typically Signal Response Time is def ined as propagation delay, t SDLY , plus length of the PWM message. However if f ilter bandwidth is chosen such that the corresponding internal output update rate (see BW parameter in EEPROM) is slower than the output digital message length, it might take a couple of output messages to update the user. Quiescent F ield Response Baseline OFFSET OUTPUT, QOUT The output value in the quiescent state (when no target deflection is applied; that is, magnetic response, BSIG = 0). CLAMP PROGRAMMING RANGE The range of values that device digital processing is customer- programmed (EEPROM parameters CLAMP_HIGH and CLAMP_LOW) to optimize what segment of the processed Full Scale Input is scaled to the Full Scale Output. This determines the extent of truncation of the high and low peaks of the output of the Digital Signal Processing stage before input to the PWM engine in the output stage. (Note: This function is not related to the sup- ply Zener clamp, for V ZSUPPLY , and the output Zener clamp, for VZOUT , which are hardware overvoltage protection features.) Device Response to Target Deflection SENSITIVITY, SENS Sensitivity is defined as the change in % duty cycle versus change in differential magnetic input signal, equation 4: OutputA (%D) – OutputB (%D) BSIGA (G) – BSIGB (G) Sens = . (4) Sensitivity is programmed in the factory to reflect the target oper- ating range of +4 mm to –4 mm of deflection. Device Accuracy QUIESCENT OUTPUT DRIFT THROUGH TEMPERATURE RANGE Due to internal component tolerances and thermal considerations, the temperature coeff icient used to determine Quiescent Output may drift from its typical initial value, QOUT init , when changes occur in the operating ambient temperature, TA. For purposes of specif ication, the Quiescent Output Drift Through Temperature Range, ΔQOUT (ΔT) , is def ined as: ΔQOUT(ΔT) = QOUT(TA) − QOUT(25°C) (5) where QOUT(TA) is the QOUT at a given TA and QOUT(25°C) is the QOUT at a TA of 25°C. Note that ΔQOUT(ΔT) should be calculated using actual measured values. SENSITIVITY DRIFT THROUGH TEMPERATURE RANGE Due to internal component tolerances and thermal considerations, the temperature coeff icient used to determine Sensitivity may drift from its typical initial value, Sens TCinit , and the expected value after customer programming (EEPROM parameters TC_ SENS_CLD and TC_SENS_HOT), when changes occur in the operating ambient temperature, T A. For purposes of specif ication, the Sensitivity Drift Through Temperature Range, ∆SensTC , is def ined as: SensTA – SensEXPECTED(TA) SensEXPECTED(TA) where SensTA is the actual Sens at the current ambient tem- perature, and SensEXPECTED(TA) is the Sens calculated based on programmed parameters.

0.90 REF

B 4 × 7° 4 × 10° A A Branded Face 2 × 2.40 ±0.10 2 × 1.27 ±0.10

5.80 REF

19.24 REF

5.78 ±0.10 7.65 ±0.10 15.58 ±0.10

23.36 REF

1.60 ±0.10 5.00 ±0.10 1.15 ±0.05 C 7.00 ±0.10 E 3 × 1.00 ±0.10 3 × 0.51 ±0.10 0.25 ±0.05 2.00 ±0.10

0.60 REF

3.00 REF

3.12 REF

6.42 REF

Pin Indent; Size and placement TBD D = Supplier emblem = Lot identiﬁer = Last three numbers of device part number and optional subtype codes = Last two digits of year of manufacture = Week of manufacture L N Y W Standard Branding Reference View LLLLLLL NNN[NNN] YYWW A B C D E For Reference Only – Not for Tooling Use Dimensions in millimeters –N OT TO SCALE Dimensions exclusive of mold ﬂash, gate burs, and dambar protrusions Exact case and lead conﬁguration at supplier discretion within limits shown Dambar removal protrusion (12×) Gate and tie burr area Thermoplastic Molded Lead Bar for alignment during shipment Hall elements (not to scale) Active Area Depth, 0.40 ±0.05 mm Branding scale and appearance at supplier discretion Ejector Pin: 1.50 REF Ejector Pin: 2.00 REF 8.00 ±0.10 F F F 100% matte tin plating, thickness = 300 – 800 micro-inches. There may not be tin plating ion areas that are trimmed. G G G G Sensor Element Tolerance Angular die placement: ±3° Ø0.4 ab c a c b PACKAGE OUTLINE DRAWING

Revision History

– December 8, 2017 Initial release

1 August 8, 2018 Updated Offset Drift Over Lifetime (page 7)

Copyright ©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.

Summary

High-Precision Linear Hall-Effect Sensor IC with Two-Wire Current-Mode PWM Output and an Integrated Rare-Earth Pellet Package

Description