A1232

A1232 ALLEGRO | Alldatasheet

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The A1232 is a highly sensitive, temperature-stable magnetic sensing device ideal for use in ring-magnet-based speed and direction systems in harsh automotive and industrial environments. It contains two bipolar, Hall-effect switches precisely arranged 1.63 mm apart. The switch outputs are thus in quadrature when interfaced with the proper ring magnet design. Internal logic processes the resulting digital signals to derive speed and direction information that is presented at the device’s outputs, OUTPUT A and OUTPUT B. The A1232 is designed for demanding, high-performance motor commutation applications. The Hall elements are photolithographically aligned to better than 1 μm. Accurately locating the two Hall elements eliminates a major manufacturing hurdle encountered in fine-pitch applications. The A1232 also has true power-on state (TPOS), the ability to detect when it is in the hysteresis band, beyond B OP , or below B RP at power-on. This provides reduced angle accuracy error due to missed start-up edges. Post-assembly factory programming at Allegro provides sensitive, symmetrical switchpoints for both switches. Extremely low-drift amplifiers maintain this symmetry. The Allegro® patented, high-frequency chopper stabilization technique cancels offsets in each channel and allows for increased signal-to-noise ratio at the input of the internal comparators. This leads to stable operation across the A1232-DS, Rev. 1

• AEC Q100 automotive qualified
• Senses speed and direction of ring magnets □ Two matched bipolar Hall-effect switches on a single substrate □ True Power-On State (TPOS): Recognizes hysteresis region at power-on
• Superior temperature stability
• Internal regulator for 3.3 to 24 V operation
• Symmetrical, high-sensitivity switchpoints
• Automotive grade □ Solid-state reliability □ Integrated ESD diodes □ Robust structures for EMC protection □ Short-circuit protected outputs □ Reverse battery protection □ –40°C to +150°C operating range Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOS Package: 8-pin TSSOP (suffix LE) Functional Block Diagram Not to scale A1232 Continued on next page... FEATURES AND BENEFITS DESCRIPTION ChannelA Channel B Hall Element Hall Element Dynamic Offset Cancellation Dynamic Offset Cancellation Hall Amp. Hall Amp. Low- Pass Filter Low- Pass Filter Low Noise Signal Recovery Low Noise Signal Recovery Output Drive and High Resolution Speed Logic Output Drive and Direction Logic Programmable Trim LDO Regulator GND OUTPUT A (Speed) OUTPUT B (Direction) VCC

4 Bit

2 Bit

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A. Description (continued) operating temperature and voltage ranges and industry leading jitter performance. An on-chip regulator provides a wide operating voltage range. The A1232 is packaged in a plastic 8-pin surface mount TSSOP (LE). This gull-wing style package is optimized for the extended temperature range of –40°C to 150°C. It is lead (Pb) free and RoHS-compliant, with a 100% matte-tin-plated leadframe. Selection Guide Part Number Packing* Mounting Ambient (TA) A1232LLETR-T 4000 units per reel 8-Pin TSSOP Surface Mount –40ºC to 150ºC *Contact Allegro™ for additional packing options. Table of Contents Specifications 3 Absolute Maximum Ratings 3 Pin-Out Diagram and Terminal List Table 3 Thermal Characteristics 4 Common Electrical Characteristics 5 Electrical Operating Characteristics 7 Magnetic Operating Characteristics 8 Magnetic Truth Table 11 Functional Desription 12 Typical Applications Operation 12 Power-On Sequence Timing 14 True Power-On State (TPOS) 14 Target Design and Selection 15 Operation with Fine-Pitch Ring Magnets 16 Chopper-Stabilized Technique 17 Regulated Supply 18 Unregulated Supply 18 Power Derating 20 Package Outline Drawing 21 RoHS COMPLIANT

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Absolute Maximum Ratings Characteristic Symbol Notes Rating Unit Forward Supply Voltage VCC 26.5 V Reverse Supply Voltage VRCC –18 V Output Off Voltage VOUT(OFF) VCC V Output Sink Current IOUT Internally Limited – Magnetic Flux Density B Unlimited – Operating Ambient Temperature TA Range L –40 to 150 ºC Maximum Junction Temperature TJ(max) 165 ºC Storage Temperature Tstg –65 to 170 ºC SPECIFICATIONS Package LE, 8-Pin TSSOP Pin-out Diagram Terminal List Table Name Number Function

3 VCC Connects power supply to chip

4 OUTPUT B Start-up Mode: Output from E2 via first Schmitt circuit

Running Mode: Direction

5 OUTPUT A Start-up Mode: Output from E1 via second Schmitt circuit

Running Mode: High-Resolution Speed

6 GND Terminal for ground connection

1, 2, 7, 8 NC No connections Pin-Out Diagram and Terminal List Table

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. THERMAL CHARACTERISTICS: may require derating at maximum conditions; see Power Derating section. Characteristic Symbol Test Conditions1 Value Units 1 Additional thermal information is available on the Allegro® web site, www.AllegroMicro.com Power Dissipation versus Ambient Temperature Temperature (ºC) Temperature (ºC) VCC(max) VCC(min) Power Derating Curve Power Dissipation, P (mW)D Maximum Allowable VCC (V) Package LE, 4-Layer PCB (R = 145ºC/W)/c113JA 1000 900 800 700 600 500 400 300 200 100 100 100 120 120 140 140 160 160 180 180 Package LE, 4-Layer PCB (R = 145ºC/W)/c113JA

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Characteristic Symbol Test Conditions Min. Typ. Max. Units Electrical Characteristics2 Supply Voltage3 VCC Operating: TA ≤ 150ºC 3.3 – 24 V Output Leakage Current IOFF Either output – <1 10 µA Supply Current ICC 2.5 3.7 6.0 mA Low Output Voltage VOUT(ON) IOUT = 20 mA B > BOP(A), B > BOP(B) – 185 500 mV Middle Output Voltage4 VOUT(MID) BRP < B < BOP, VPULL-UP = 12 V, RLOAD = 12 kΩ – 6 – V Output Sink Current, Middle IOUT(MID) BRP < B < BOP, VPULL-UP = 12 V, RLOAD = 12 kΩ – 0.5 – mA Output Sink Current Limit IOM VCC = 12 V 30 – 70 mA Chopping Frequency fC – 750 – kHz Output Rise Time5 tr CS = 20 pF, RLOAD = 820 Ω – 1.8 – µs Output Fall Time5 tr CS = 20 pF, RLOAD = 820 Ω – 1.2 – µs Power-On Time6 tON – 50 65 µs Power-On State7 POS t < tON B = 0 G VOUT(OFF) – t ≥ tON BRP < B < BOP VOUT(MID) – B > BOP VOUT(ON) – B < BRP VOUT(OFF) – Transient Protection Characteristics Supply Zener Clamp Voltages VZ ICC = 9 mA, TA = 25ºC 28 46 – V Supply Zener Current8 IZ VS = 28 V – – 9.0 mA Reverse Supply Current IRCC VRCC = –18 V, TJ < TJ(max) – 2 15 mA ELECTRICAL CHARACTERISTICS: valid over full operating temperature range unless otherwise noted; typical data applies to VCC = 12 V and TA = 25°C; see typical application circuits 2 Output related specifications listed in the characteristic column are applicable to each output transistor unless otherwise noted. 3 Maximum voltage operation must not exceed maximum junction temperature. Refer to power de-rating curves. 4 VOUT(MID) and IOUT(MID) specified typical values are found when connected as shown in Figure 10 and Figure 11. This information is only guaranteed available before the first magnetic field transition has occurred and after the power-on time has occurred. The output state transition from the t < tON POS and the t > tON POS is not considered the first magnetic field transition. See Figure 1 and the Magnetic Truth Table for power-on behavior.

5 CS = oscilloscope probe capacitance

6 Power-On Time is the duration from when VCC rises above VCC(MIN) until both outputs have attained valid states. 7 POS for both outputs is undefined for VCC < VCC(MIN). Use of a VCC slew rate greater than 25 mV/µs is recommended. 8 Maximum specification limit is equivalent to ICC(MAX) + 3 mA.

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Characteristic Symbol Test Conditions Min. Typ. Max. Units Magnetic Characteristics10 Operate Point: B > BOP BOP(A), BOP(B) – 10 30 G Release Point: B < BRP BRP(A), BRP(B) –30 –10 – G Hysteresis: BOP(A) - BRP(A), BOP(B) - BRP(B) BHYS(A), BHYS(B) 5 20 35 G Symmetry: Ch A, Ch B B OP(A) + BRP(A), BOP(B) + BRP(B) SYMA, SYMB –35 – 35 G Operate Symmetry: B OP(A) – BOP(B) SYMAB(OP) –25 – 25 G Release Symmetry: B RP(A) – BRP(B) SYMAB(RP) –25 – 25 G MAGNETIC CHARACTERISTICS: valid over full operating temperature range unless otherwise noted; typical data applies to V CC = 12 V and TA = 25°C; see typical application circuits 9 1G (gauss) = 0.1 mT (millitesla) 10 Magnetic flux density, B, is indicated as a negative value for north-polarity magnetic fields, and as a positive value for south-polarity magnetic fields. The algebraic conven- tion used here supports arithmetic comparison of north and south polarity values, where the relative strength of the field is indicated by the absolute value of B, and the sign indicates the polarity of the field (for example, a –100 G field and a 100 G field have equivalent strength, but opposite polarity).

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. ELECTRICAL OPERATING CHARACTERISTICS Average Supply Current versus Supply Voltage I (mA) CC V (V)CC 2 61 01 41 82 22 6 5.5 6.0 6.5 2.5 3.0 3.5 4.0 4.5 5.0 T (ºC) A -40 150 Average Supply Current versus Ambient Temperature I (mA) CC T (ºC)A -60- 40 -200 20 40 60 80 100 120 140 160 5.5 6.0 6.5 2.5 3.0 3.5 4.0 4.5 5.0 V( V)CC 3.3 Average Low Output Voltage versus Ambient Temperature for I= 20 mAOUT V (mV) OUT(ON) T (ºC)A -60- 40 -200 20 40 60 80 100 120 140 160 300 350 450 400 500 100 150 200 250 V( V)CC 3.3

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. MAGNETIC CHARACTERISTICS Channel A: Average Operate & Release Points versus Supply Voltage B & B (G) OP RP V (V)CC 2 61 0 14 18 22 26 -30 -20 -10 T (ºC)A -40 150 BOP -40 150 BRP Channel A: Average Operate & Release Points versus Ambient Temperature B & B (G) OP RP TA (ºC) -60 -40- 20 02 04 06 08 0 100 120 140 160 -30 -20 -10 VCC (V) 3.5 BOP 3.5 BRP Channel B: Average Operate & Release Points versus Supply Voltage B & B (G) OP RP V (V)CC 2 61 0 14 18 22 26 -30 -20 -10 T (ºC)A -40 150 BOP -40 150 BRP Channel B: Average Operate & Release Points versus Ambient Temperature B & B (G) OP RP TA (ºC) -60 -40- 20 02 04 06 08 0 100 120 140 160 -30 -20 -10 VCC (V) 3.5 BOP 3.5 BRP Channel A& B: Average Switchpoint Hysteresis versus Supply Voltage B & B (G) HYS(A) HYS(B) V (V)CC 2 61 0 14 18 22 26 T (ºC)A -40 150 Ch. A -40 150 Ch. B Channel A& B: Average Switchpoint Hysteresis versus Ambient Temperature B & B (G) HYS(A) HYS(B) TA (ºC) -60 -40- 20 02 04 06 08 0 100 120 140 160 VCC (V) 3.5 Ch. A 3.5 Ch. B Additional Magnetic Characteristics on next page.

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Average Operate Point Symmetry versus Supply Voltage SYM AB(OP) (G) VCC (V) 2 61 0 14 18 22 26 -25 -20 -15 -10 T A (ºC) -40 150 Average Operate Point Symmetry versus Ambient Temperature SYM AB(OP) (G) T (ºC)A -60- 40 -200 20 40 60 80 100 120 140 160 -25 -20 -15 -10 V( V) CC 3.3 Average Release Point Symmetry versus Supply Voltage SYM AB(RP) (G) VCC (V) 2 61 0 14 18 22 26 -25 -20 -15 -10 TA (ºC) -40 150 Average Release Point Symmetry versus Ambient Temperature SYM AB(RP) (G) T (ºC)A -60- 40 -200 20 40 60 80 100 120 140 160 -25 -20 -15 -10 V( V) CC 3.3 Additional Magnetic Characteristics on next page. Continued from previous page.

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Channel B Symmetry versus Supply Voltage SYM B (G) VCC (V) 2 61 0 14 18 22 26 -35 -28 -21 -14 TA (ºC) -40 150 Channel B Symmetry versus Ambient Temperature SYM B (G) T (ºC)A -60- 40 -200 20 40 60 80 100 120 140 160 -35 -28 -21 -14 V( V) CC 3.3 Continued from previous page. Channel A Symmetry versus Supply Voltage SYM A (G) VCC (V) 2 61 0 14 18 22 26 -35 -28 -21 -14 T A (ºC) -40 150 Channel A Symmetry versus Ambient Temperature SYM A (G) T (ºC)A -60- 40 -200 20 40 60 80 100 120 140 160 -35 -28 -21 -14 V( V) CC 3.3

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Conditions Magnetic Field BE1 at Hall Element E1 Magnetic Field BE2 at hall Element E2 OUTA OUTB t < tON – – X X t > tON Power-On Time has occurred and fields BE1 and BE2 have not yet each transitioned BE1 < BRP(A) BE2 < BRP(B) H H BE1 < BRP(A) BRP(B) < BE2 < BOP(B) H M BE1 < BRP(A) BE2 > BOP(B) H L BRP(A) < BE1 < BOP(A) BE2 < BRP(B) M H BRP(A) < BE1 < BOP(A) BRP(B) < BE2 < BOP(B) M M BRP(A) < BE1 < BOP(A) BE2 > BOP(B) M L BE1 > BOP(A) BE2 < BRP(B) L H BE1 > BOP(A) BRP(B) < BE2 < BOP(B) L M BE1 > BOP(A) BE2 > BOP(B) L L t > tON BE1 and BE2 have already each transitioned at least one time Any Any SPD DIR Key L = VOUT(ON), Low M = VOUT(MID), Middle H = VOUT(OFF), High SPD = High-Resolution Speed DIR = Direction X = Output Not Defined Magnetic Truth Table

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. FUNCTIONAL DESCRIPTION Typical Applications Operation As shown in Figure 1, the bipolar Hall-effect switches in the A1232 turn on when a south-polarity magnetic field perpendicu- lar to the Hall element exceeds the operate point threshold (BOP); the switches turn off when a north-polarity magnetic field of suf- ficient strength exceeds the release point (BRP) The difference in the magnetic operate and release points is the hysteresis (BHYS) of the device. BHYS = BOP - BRP This built-in hysteresis allows clean switching of the output even in the presence of external mechanical vibration and electrical noise. V+ VOUT(OFF) Switch to Low Switch to High VOUT(ON) V OUTPUT B- 0 B+ B RP BOP BHYS The Hall-effect sensing elements are precisely located 1.63 mm apart across the width of the package (see Figure 2: A1232 Sensors and Relationship to Target). When used with a properly designed ring magnet, the outputs of the two switches will be in quadrature, or 90 degrees out of phase. The relationship of the various signals and the typical system timing is shown in Figure 3: Typical System Timing. During operation (Run Mode), the output of the internal switches is encoded into a pair of signals representing the speed and direction of the target (see Functional Block Diagram on page 1). These signals appear at the OUTPUT A (speed) and OUTPUT B (direction) pins. OUTPUT B (direction) is a logic signal indicating the direction of rotation (assuming a ring magnet target). It is defined as off (high) for targets moving in the direction from E1 to E2 and on (low) for the direction E2 to E1. For instances when the rotation direction of the target changes, OUTPUT B changes state and then the speed output (OUTPUT A) resumes after a short delay d, approximately 3 to 5 µs). OUTPUT B (direction) is always updated before OUTPUT A (speed) and is updated at each Hall element’s switching transition. This sequencing and built-in delay allow the tracking of target speed or position with an external counter without the loss of pulses. OUTPUT A (speed) is a logic output representing the combined (XOR’ed) outputs of the two Hall-effect switches. This produces a digital output edge at each switch’s transition beyond B OP and BRP. It will change state as the magnetic poles pass across the device at a rate given by Equation A and with a period given by Equation B: f (Hz) =OUTPUTA T (s) =OUTPUTA V× /c119 60 seconds fOUTPUTA × 2 (A) (B) Example for ω = 2 and V = 60 rpm (based on target depicted in Figure 3): PCB N N S S Z E2 to Output B (Directio n) = On (L ow) E1 to E2 Output B (Direc tion ) = Off (H igh) Figure 2: A1232 Sensor and Relationship to Target Figure 1: Output Voltage in Relation to Magnetic Flux Density Received

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. f (Hz) =OUTPUTA T (s) =OUTPUTA 60 × 2 60 seconds 4 Hz × 2 = 4 Hz =250 ms Key:

• V = Axle Shaft Speed (rpm)
• ω = Number of North and South Pole-Pairs per Axle Mechanical Revolution
• f = Cycles per Second (Hz)
• T = Time Duration of One Mechanical Period (s) Immediately after turn-on, the device will be in a special True Power-On State (TPOS) mode. This mode allows the device to detect and indicate that one or both of the switches is in the hys- teresis region, i.e., that the applied field is between B OP and BRP. Ring magnet starts rotating Magnetic Field at Hall Element E1 (pin 1 side) Magnetic Field at Hall Element E2 (pin 8 side) Internal Channel A Internal Channel B DIRECTION OUTPUT B XOR SPEED OUTPUT A V = VOUT(OFF) V = VOUT(ON) Pin 1 to 8 tON POS Second Hall Transition First Hall Transition t expires (typ. 50 µs)ON Power ON Pin 8 to 1 td BRP(E1) BOP(E2) BOP(E1) BRP(E2) Internal Stage Output Stage time + V = VOUT(MID) D i r e c t i o n C h a n g e Figure 3: Typical System Timing

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Power-On Sequence and Timing The states of OUTPUT A and OUTPUT B are only valid when the supply voltage is within the specified operating range CC(min) ≤ VCC ≤ VCC(max)) and the power-on time has elapsed ( t > tON). Refer to Figure 4: Power-On Sequence and Timing for an illustration of the power-on sequence. True Power-On State (TPOS) Immediately after power-on (Figure 4, after tON has elapsed), OUTPUT A and OUTPUT B will follow the state of the corre- sponding switches rather than the outputs of the speed and direc- tion logic. This mode allows the device to detect and indicate that one or both of the switches is in the hysteresis region (i.e., that the applied field is between B OP and BRP). Additionally while in TPOS mode, the outputs will report if the corresponding switch is beyond B OP or below BRP. These output states, VOUT(ON) for B > BOP and VOUT(OFF) for B < BRP, reflect the output polarity and level corresponding to the target feature (magnet pole) nearest the switch. In Run Mode, the outputs will be driven only either high or low, that is, to V OUT(OFF) or VOUT(ON), as the A1232 indicates the movement of the target. (The precise voltage levels are dictated by the load circuit and pull-up voltage on each output.) While the A1232 is in TPOS mode and either or both of the sensors are in their hysteresis range (B OP < B < BRP), a third state is present on the corresponding output as shown in Figure 5: Power-On State vs. Applied Field. Dynamic current limiting circuitry holds the output sink current at I OUT(MID), creating an output state known as VOUT(MID). The output voltage corresponding to VOUT(MID) is given by: VOUT(MID) = VOUT(OFF) - [IOUT(MID) × RLOAD] By choosing the correct load resistor, RLOAD, this middle output state can be made equal to half of the pull-up voltage. This is the case when using the typical application circuits shown in Figures 10 and 11. See the Circuit Analysis Example table following the typical application circuits for more details. The host must be able to detect this middle state in order to make use of the TPOS information. After exiting TPOS mode, only the standard low (V OUT(ON)) and high (VOUT(OFF)) output states are produced to indicate target speed and direction. Both outputs exit TPOS mode together, and only after each switch has detected a magnetic field transition from their power-on state (that is, beyond B OP or BRP). Internal comparators prevent the outputs from entering the IOUT(MID) state if it was not activated at the moment of power-on. Once having exited TPOS mode, the outputs will not re-enter TPOS mode as long as power is maintained. NOTE: The states of OUTPUT A and OUTPUT B are only valid when the supply voltage is within the specified oper- ating range and the power-on time has elapsed. See Power-on Sequence and Timing for details. B < BRP B< B < BRP OP B > BOP VCC VCC(MIN) VOUT(OFF) VOUT(MID) VOUT(ON) Output Undefined for V< VCC CC(MIN) V V tON time time Figure 4: Power-on Sequence and Timing V+ VOUT(OFF) VOUT(MID) VOUT(ON) V OUTPUT B- B+ B RP BOP BHYS Figure 5: Power-On State vs. Applied Field

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Target Design/Selection Internal logic circuitry produces outputs representing the speed (OUTPUT A) and direction (OUTPUT B) of the magnetic field passing across the face of the package. The response of the device to the magnetic field produced by a rotating ring magnet is shown in Figure 3. (Note the phase shift between the two integrated Hall elements.) For the direction signal to be correct, the switch points of the Hall elements must be adequately matched and a quadrature relation- ship must be maintained between the target’s magnetic poles and the spacing of the two Hall elements (E1 and E2). A quadrature relationship produces Hall switch phase separation of 90°. For optimal performance, the device should be actuated by a ring magnet that presents to the front of the device fields with a pole pitch two times the Hall element-to-element spacing of 1.63 mm. The period (T) is then equal to twice the pole pitch (P), as depicted by Figure 6 and Equation C. This will produce a sinu- soidal magnetic field whose period corresponds to four times the element-to-element spacing: For P = 2 × 1.63 mm = 3.26 mm (C) T = 2 × 3.26 mm = 6.52 mm The A1232 requires a minimum magnetic field input to guarantee switching, as described in Equation D: B PK-PK = BOP(MAX) + |BRP(MIN)|, (D) BPK-PK = 30 G + 30 G = 60 G Based on the maximum operate point (BOP(MAX)) and the mini- N NS SS E1E2 Pin 1 Air Gap Pin 8 A1232 Branded Face of Package Element Pitch Direction of Rotation Ring Magnet Figure 6a: Device Orientation to Target NSSS N Direction of Rotation Ring Magnet Target Element Pitch Target Magnetic Profile Figure 6b: Mechanical Position (Target moves past device pin 1 to pin 8) Figure 6: Target Profiling During Operation -10 -20 -30 -40 0 + B (S)OP(MAX) B( N)RP(MIN) Time Flux Density , B (G Figure 7a: Example of Ring Target Magnetic Profile 800 700 600 500 400 300 200 100 0 +Air GapPeak-to-Peak Flux Density , B (G) PK-PK Figure 7b: Example of Ring Magnetic Flux Density Peak-to-Peak vs. Air Gap Figure 7: Example of Target Magnetic Field Profile

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. mum release point (BRP(MIN)), it is recommended to ensure the target’s magnetic input signal remains above 60 G peak-to-peak when centered about 0 G. If the system has a magnetic offset component present, field values B OP and BRP must be exceeded to continue switching. Thus for optimal performance it is rec- ommended to interface the sensor with an alternating bipolar magnetic field profile that continuously exceeds B OP(MAX) and BRP(MIN). As depicted in Figure 7, the sinusoidal profile created by the alternating north and south poles of a rotating ring magnet decreases in magnitude as the air gap is increased. The minimum peak-to-peak flux density must be accounted for in system air gap tolerances. Operation with Fine-Pitch Ring Magnets For targets with a circular pitch of less than 4 mm, a performance improvement can be observed by rotating the front face of the device (refer to Figure 8). This rotation decreases the effective Hall element-to-element spacing (D), provided that the Hall ele- ments are not rotated beyond the width of the target. E2 E2S N S D D cos α Target Profile of Rotation Target Circular Pitch (P) Target Face Width (F) F < D sin a α Rotated AlignmentNormal Coplanar Alignment Figure 8: Operation with Fine-Pitch Ring Magnets

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. A limiting factor for switch point accuracy when using Hall- effect technology is the small signal voltage developed across the Hall plate. This voltage is proportionally small relative to the offset that can be produced at the output of the Hall sensor. This makes it difficult to process the signal and maintain an accurate, reliable output over the specified temperature and voltage range. Chopper Stabilization is a proven approach used to minimize Hall offset. The Allegro patented technique, dynamic quadrature offset cancellation, removes key sources of the output drift induced by temperature and package stress. This offset reduction technique is based on a signal modulation-demodulation process. Figure 9: Example of Chopper Stabilization Circuit (Dynamic Offset Cancellation) illustrates how it is implemented. The undesired offset signal is separated from the magnetically induced signal in the frequency domain through modulation. The subsequent demodulation acts as a modulation process for the offset causing the magnetically induced signal to recover its original spectrum at baseband while the dc offset becomes a high frequency signal. Then, using a low-pass filter, the signal passes while the modulated DC offset is suppressed. Allegro’s innovative chopper-stabilization technique uses a high frequency clock. The high-frequency operation allows a greater sampling rate that produces higher accuracy, reduced jitter, and faster signal processing. Additionally, filtering is more effective and results in a lower noise analog signal at the sensor output. Devices such as the A1232 that utilize this approach have an extremely stable quiescent Hall output voltage, are immune to thermal stress, and have precise recoverability after temperature cycling. This technique is made possible through the use of a BiCMOS process which allows the use of low offset and low noise amplifiers in combination with high-density logic and sample and hold circuits. Chopper Stabilization Technique Regulator Amp Low- Pass Filter Sample and Hold Figure 9: Example of Chopper Stabilization Circuit (Dynamic Offset Cancellation)

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Regulated Supply This device requires minimal protection circuitry for operation from a regulated power supply. The on-chip voltage regulator provides immunity to power supply variations between 3.3 V and 18 V . Because the device has open-drain outputs, pull-up resistors must be used. If protection against coupled and injected noise is required, then a simple bypass capacitor filter is recommended. Refer to the circuit in Figure 10 for an example. Unregulated Supply In applications where the A1232 receives its power from an unregulated source such as a car battery, additional measures may be required to protect it against supply-side transients. Specifica- tions for such transients will vary so protection-circuit design should be optimized for each application. For example, the circuit shown in Figure 11 includes an optional Zener diode that offers additional high voltage load-dump protection and noise filtering by means of a series resistor and capacitor. In addition to this, an optional series diode is included, and this protects against high- voltage reverse battery conditions beyond the capability of the built-in reverse-battery protection. VOUTPUT A VSUPPLY VOUTPUT B R=LOAD 12 k/c87 R=LOAD 12 k/c87 100 nF GND VCC OUTPUT A OUTPUT B A1232 Figure 10: Typical Application Circuit for Regulated Power Supply VOUTPUTA VSUPPLY VOUTPUTB R=LOAD 12 k/c87 R=LOAD 12 k/c87 C=OUT 4.7 nF C=OUT 4.7 nF 100 /c87 100 nF A A AD iodes are optional for systems not exceeding V and V depending onZ RCC Conducted Immunity requirements. GND VCC OUTPUT A OUTPUT B A1232 Figure 11: Typical Application Circuit for Unregulated Power Supply

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. VSUPPLY COUTPUT(A) COUTPUT(B) IOUTPUT(A) IOUTPUT(B) VPULL-UP(A) VPULL-UP(B) RLOAD(A) RLOAD(B) OUTA OUTB ToAll Subcircuits A1232 + + Figure 12: Application Circuit Example Table 1: Circuit Analysis Example Startup Operation Analysis Condition VPULL-UP(A/B) (V) RLOAD(A/B) (Ω) OUTPUT (V) IOUTPUT(A/B) (Internally Limited) t > tON Before first magnetic field transition of each channel BRP < B < BOP 3.3 2.8 k 1.9 0.5 5 4.5 k 2.75 0.5 12 12 k 6 0.5 18 18 k 9.0 0.5 Normal Operation Analysis Condition VPULL-UP(A/B) (V) RLOAD(A/B) (Ω) OUTPUT (mV)12 IOUTPUT(A/B)13 t > tON After first magnetic field transition of each channel B > BOP 3.3 2.8 k 500 1 5 4.5 k 500 1 12 11.84 k 160 1 18 875 500 20 12Except for the 12 V typical calculations, the output on voltage is assumed worse case of 500 mV. Actual application values will vary. 13Output sink current calculations are for demonstrational purposes only and actual IOUT(ON) and VOUT(ON) values will vary with different pull-up source and resistor values, in addition to TJ and VCC. During normal operation the device’s output sink current is internally limited to between 30 mA and 70 mA.

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. POWER DERATING 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 T J (Thermal data is also available on the Allegro MicroSystems Web site, www.AllegroMicro.com). 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 (R θJC) 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 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) TJ = TA + ΔT (3) For example, given common conditions such as: TA= 25°C, VCC = 12 V , ICC = 4 mA, and RθJA = 145°C/W, then: PD = VCC × ICC = 12 V × 4 mA = 48 mW ΔT = PD × RθJA = 48 mW × 145°C/W = 7°C TJ = TA + ΔT = 25°C + 7°C = 32°C A worst-case estimate (PD (max)) represents the maximum allow- able power level, without exceeding TJ (max), at a selected RθJA and TA. Example: Reliability for VCC at TA = 150°C, package LE, using a four-layer PCB. Observe the worst-case ratings for the device, specifically: R θJA = 145°C/W, TJ (max) = 165°C, VCC (max) = 24 V , and ICC (max) = 6 mA. Calculate the maximum allowable power level (P D (max)). First, invert equation 3: ΔT (max) = 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) = ΔT (max) ÷ RθJA PD (max) = 15°C ÷ 145°C/W = 103 mW Finally, invert equation 1 with respect to voltage: VCC (est) = PD (max) ÷ ICC (max) VCC (est) = 103 mW ÷ 6 mA = 17.2 V The result indicates that, at TA, the application and device can dissipate adequate amounts of heat at voltages ≤ VCC (est). Compare VCC (est) to VCC (max). If VCC (est) ≤ VCC (max), then 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. In cases where the VCC (max) level is known, and the system designer would like to determine the maximum allowable ambi- ent temperature (TA (max)), the calculations can be reversed. For example, in a worst case scenario with conditions VCC (max) =

24 V and ICC (max) = 6 mA, using equation 1 the largest possible

amount of dissipated power is: PD = VIN × IIN PD = 24 V × 6 mA = 144 mW Then, by rearranging equation 3: TA (max) = TJ (max) – ΔT TA (max) = 165°C/W – (144 mW × 145°C/W) In another example, the maximum supply voltage is equal to VCC(MIN). Therefore, VCC (max) = 3.3 V and ICC (max) = 6 mA. By using equation 1 the largest possible amount of dissipated power is: P D = VIN × IIN PD = 3.3 V × 6 mA = 19.8 mW Then, by rearranging equation 3: TA (max) = TJ (max) – ΔT TA (max) = 165°C/W – (19.8 mW × 145°C/W) TA (max) = 165°C/W – 2.9°C = 162.1°C

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. PACKAGE OUTLINE DRAWING For Reference Only – Not for Tooling Use (Reference MO-153 AA) 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 3.00 ±0.10 1.50 6.40 BSC 6.40 BSC4.40 ±0.10 1.38 1.63 1.70 0.45 0.65 D D B B C C E E D D D D Branded Face 0.10 C 0.30 0.19

0.65 BSC

0.25 BSC

0.15 0.05

1.10 MAX

C 0.02 0.09 0.60 1.00 REF+0.15 -0.10 SEATING PLANE GAUGE PLANE PCB Layout Reference View Standard Branding Reference View NNN YYWW A A = Last 3 digits of device part number = Supplier emblem = Last two digits of year of manufacture = Week of manufacture N Y W Terminal #1 mark area Reference land pattern layout (reference IPC7351 SOP65P640X110-8M); all pads minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances; when mounting on a multilayer PCB, thermal vias can improve thermal dissipation (reference EIA/JEDEC Standard JESD51-5) Branding scale and appearance at supplier discretion Hall elements (E1 and E2), not to scale ActiveA rea Depth = 0.36 mm REF Figure 13: Package LE, 8-Pin TSSOP

Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOSA1232 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. For the latest version of this document, visit our website: www.allegromicro.com

Revision History

Revision Revision Date Description of Revision – December 10, 2014 Initial Release

1 September 21, 2015 Added AEC Q100 qualification under Features and Benefits

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