A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC FEATURES AND BENEFITS DESCRIPTION Optimized robustness to magnetic offset variation Small signal lockout for immunity against vibration Tight duty cycle and timing accuracy over full operating temperature range True zero-speed operation Air gap independent switch points Large operating air gaps achieved through use of gain adjust and offset adjust circuitry Defined power-on state (POS) Wide operating voltage range Digital output representing target profile Single chip sensing IC for high reliability Small mechanical size Fast startup Undervoltage lockout (UVLO) The A1667 is a true zero-speed ring magnet sensor integrated circuit (IC) consisting of an optimized Hall IC available in two package options that provides a user-friendly solution for digital ring magnet sensing applications. The sensor incorporates a dual element Hall IC that switches in response to differential magnetic signals created by a ring magnet. The IC contains a sophisticated compensating circuit designed to eliminate the detrimental effects of magnet and system offsets. Digital processing of the analog signal provides zero-speed performance independent of air gap and also dynamic adaptation of device performance to the typical operating conditions found in automotive applications (reduced vibration sensitivity). High-resolution peak detecting DACs are used to set the adaptive switching thresholds of the device. Hysteresis in the thresholds reduces the negative effects of any anomalies in the magnetic signal associated with the targets used in many automotive applications. PACKAGES: 4-Pin SIP (suffix K) 8-Pin SOIC (suffix L) The open-drain output is configured for three-wire applications. This sensor is ideal for obtaining speed and duty cycle Continued on the next page... KEY APPLICATIONS * Automotive - Transmissions Applications * 2- and 3-Wheeler Speed Applications * White Goods - Drum Speed Applications Not to scale Functional Block Diagram VCC Voltage Regulator Automatic Gain Control Hall Amp Offset Adjust Threshold Comparator PDAC PThresh VPROC Reference Generator NDAC Threshold Logic NThresh TEST Current Limit Output Transistor VOUT GND A1667-DS, Rev. 3 MCO-0000168 October 4, 2018 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC DESCRIPTION (continued) information using ring magnet based systems in applications such as automotive transmissions and industrial equipment. The A1667 is available in a 4-pin SIP through-hole package (suffix K) and an 8-pin SOIC surface-mount package (suffix L). Both packages are lead (Pb) free with 100% matte-tin-plated leadframes. SELECTION GUIDE Part Number Packaging Packing* A1667LK-T 4-pin SIP through hole Bulk, 500 pieces per bag A1667LLTR-T 8-pin SOIC surface mount 3000 pieces per 13-in. reel *Contact AllegroTM for additional packing options ABSOLUTE MAXIMUM RATINGS Characteristic Symbol Supply Voltage VCC Reverse Supply Voltage VRCC Notes See Power Derating section Rating Unit 26.5 V -18 V Reverse Supply Current IRCC -50 mA Reverse Output Voltage VROUT -0.5 V 25 mA -40 to 150 C Output Sink Current IOUT Operating Ambient Temperature TA Maximum Junction Temperature TJ(max) 165 C Tstg -65 to 170 C Storage Temperature Range L PINOUT DIAGRAMS AND TERMINAL LIST TABLE Terminal List Number 1 2 3 1 8 2 7 3 6 4 5 4 Package K, 4-Pin SIP Package L, 8-Pin SOIC Name Function K L 1 1 VCC Supply voltage 2 2 VOUT Device output 3 3 TEST Test pin (float or tie to GND) 4 4 GND Ground - 5,6,7,8 NC No connect* * Pins 5, 6, 7, and 8 should be externally connected to Ground. Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 2 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC OPERATING CHARACTERISTICS: Valid over operating voltage and temperature ranges, unless otherwise noted Characteristics Symbol Test Conditions Min. Typ. [1] Max. Unit 4 - 24 V 2.7 3.5 3.95 V - - -10 mA 26.5 - - V - - 15 mA ELECTRICAL CHARACTERISTICS Supply Voltage VCC Undervoltage Lockout (UVLO) Operating, TJ < TJ(max) VCC(UV) Reverse Supply Current IRCC VCC = -18 V Supply Zener Clamp Voltage VZ ICC = 15 mA, TA = 25 C Supply Zener Current IZ TA = 25C, TJ < TJ(max), continuous, VZ = 26.5 V Supply Current Test Pin Zener Clamp Voltage ICC [2] Output off 4 7 12 mA Output on 4 7 12 mA - 6 - V Connected as in figure 6 - High - - fOP < 200 Hz; VCC > VCC(min) - - 2 ms VTESTZ POWER-ON STATE CHARACTERISTICS Power-On State Power-On Time [3] POS tPO OUTPUT STAGE Low Output Voltage Output Zener Clamp Voltage VOUT(SAT) ISINK = 10 mA, Output = on VZOUT - 100 250 mV 26.5 - - V Output Current Limit IOUT(LIM) VOUT = 12 V, TJ < TJ(max) 25 45 70 mA Output Leakage Current IOUT(OFF) Output = off, VOUT = 24 V - - 10 A Output Rise Time tr RL = 1 k, CL = 4.7 nF, VPULLUP = 12 V, 10% to 90%, connected as in figure 6 - 10 - s Output Fall Time tf RL = 1 k, CL = 4.7 nF, VPULLUP = 12 V, 10% to 90%, connected as in figure 6 - 0.6 2 s -150 - 150 G 0 - 12 kHz DIGITAL-TO-ANALOG CONVERTER (DAC) CHARACTERISTICS Allowable User-Induced Differential Offset [4][5] BDIFFEXT User induced differential offset SWITCHPOINT CHARACTERISTICS Operational Switching Frequency fOP Bandwidth f-3dB Cutoff frequency for low-pass filter 15 20 - kHz Operate Point BOP % of peak-to-peak VPROC referenced from PDAC to NDAC, BSIG > BSIG(MIN), VOUT high to low 65 70 75 % Release Point BRP % of peak-to-peak VPROC referenced from PDAC to NDAC, BSIG > BSIG(MIN), VOUT low to high 25 30 35 % Running Mode Lockout Enable (LOE) VLOE(RM) VPROC(PK-PK) < VLOE(RM) = output switching disabled - 100 - mV Running Mode Lockout Release (LOR) VLOR(RM) VPROC(PK-PK) < VLOR(RM) = output switching enabled - 220 - mV Continued on the next page... Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 3 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC OPERATING CHARACTERISTICS (continued): Valid over operating voltage and temperature ranges, unless otherwise noted Characteristics Symbol Test Conditions Min. Typ. [1] Max. Unit CALI Possible reduced edge detection accuracy, duty cycle not guaranteed - 1 6 electrical edge Running mode operation, bounded for decreasing BSIG, unlimited for increasing BSIG - Continuous - - CALIBRATION Initial Calibration [6] Update Method OPERATING CHARACTERISTICS Operating Signal Range BSIG Differential magnetic signal operation within specification 30 - 1400 G Relative Repeatability [7] TE 60 pole-pair target, using 100 GPK-PK ideal sinusoidal signal, TA = 150C, and fOP = 1000 Hz - 0.12 - degrees Single instantaneous air gap peak-to-peak amplitude change, fOP < 500 Hz, VPROC(pk-pk) > VLOE after sudden AG change - 40 - %PK-PK Maximum Single Outward Sudden Air Gap Change [8] AGMAX [1] Typical data is at VCC = 12 V and TA = 25C, unless otherwise noted. Performance may vary for individual units, within the specified maximum and minimum limits. [2] Sustained voltages beyond the clamp voltage may cause permanent damage to the IC. [3] Power-On Time is the time required to complete the internal Automatic Offset Adjust; the DACs are then ready for peak acquisition. [4] The device compensates for magnetic and installation offsets. Offsets greater than specification in gauss may cause inaccuracies in the output. [5] 1 G (gauss) = 0.1 mT (millitesla). [6] For power-on frequency, f OP < 200 Hz. Higher power-on frequencies may result in more input magnetic cycles until full output edge accuracy is achieved, including the possibility of missed output edges. [7] The repeatability specification is based on statistical evaluation of a sample population, evaluated at 1000 Hz. [8] Single maximum allowable air gap change in outward direction (increase in air gap). Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 4 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC CHARACTERISTIC PERFORMANCE Supply Current (Off) versus Supply Voltage 14 14 12 12 10 VCC (V) 8 4 12 24 6 ICCOFF (mA) ICCOFF (mA) Supply Current (Off) versus Ambient Temperature TA (C) -40 25 150 8 6 4 4 2 2 0 0 -50 0 50 100 150 0 10 30 VCC (V) Supply Current (On) versus Ambient Temperature Supply Current (On) versus Supply Voltage 14 14 12 12 8 4 12 24 6 ICCON (mA) 10 VCC (V) TA (C) -40 25 150 8 6 4 4 2 2 0 0 -50 0 50 100 0 150 10 TA (C) 160 140 BOP, BRP (%) 120 100 80 60 40 20 0 -50 0 50 TA (C) 30 Switchpoints versus Ambient Temperature VCC = 12 V 180 20 VCC (V) Output Saturation Voltage versus Ambient Temperature VOUT(SAT) (mV) 20 TA (C) 10 ICCON (mA) 10 100 150 100 90 80 70 60 50 40 30 20 10 0 BOP BRP -50 0 50 100 150 T A (C) Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 5 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC THERMAL CHARACTERISTICS: May require derating at maximum conditions; see application information Characteristic Symbol Test Conditions* RJA Package Thermal Resistance Value Units Package K, 1-layer PCB with copper limited to solder pads 177 C/W Package L, 1-layer PCB with copper limited to solder pads 140 C/W Package L, 4-layer PCB based on JEDEC standard 80 C/W *Additional thermal data available on the Allegro Website. 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 VCC(max) Package L, 4-layer PCB (RJA = 80C/W) Package L, 1-layer PCB (RJA = 140C/W) Package K, 1-layer PCB (RJA = 177C/W) VCC(min) 20 40 60 80 100 120 140 160 180 Temperature (C) Power Dissipation versus Ambient Temperature Power Dissipation, PD (mW) Maximum Allowable VCC (V) Power Derating Curve 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 Package L, 4-layer PCB (RJA = 80 C/W) Package L, 1-layer PCB (RJA = 140 C/W) Package K, 1-layer PCB (RJA = 177 C/W) 20 40 60 80 100 120 140 160 180 Temperature (C) Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 6 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC FUNCTIONAL DESCRIPTION HALL TECHNOLOGY The single-chip differential Hall-effect sensor IC contains two Hall elements as shown in figure 1, which simultaneously sense the magnetic profile of the ring magnet. The magnetic fields are sensed at different points (spaced at a 2.2 mm pitch), generating a differential internal analog voltage, VPROC, that is processed for precise switching of the digital output signal. The Hall IC is self-calibrating and also possesses a temperaturecompensated amplifier and offset cancellation circuitry. Its voltage regulator provides supply noise rejection throughout the operating voltage range. Changes in temperature do not greatly affect this device due to the stable amplifier design and the offset rejection circuitry. The Hall transducers and signal processing electronics are integrated on the same silicon substrate, using a proprietary BiCMOS process. TARGET PROFILING DURING OPERATION An operating device is capable of providing digital information that is representative of the mechanical features of a rotating gear. The waveform diagram in figure 3 presents the automatic translation of the mechanical profile, through the magnetic profile that it induces, to the digital output signal of the A1667. No addi- tional optimization is needed and minimal processing circuitry is required. This ease of use reduces design time and incremental assembly costs for most applications. DETERMINING OUTPUT SIGNAL POLARITY In figure 3, the top panel, labeled Mechanical Position, represents the mechanical features of the target ring magnet and orientation to the device. The bottom panel, labeled Device Output Signal, displays the square waveform corresponding to the digital output signal that results from a rotating ring magnet configured as shown in figure 2. That direction of rotation (of the target side adjacent to the package face) is: perpendicular to the leads, across the face of the device, from the pin 1 side to the pin 4 side. This results in the device output switching from low to high output state as the leading edge of a north magnetic pole passes the device face. In this configuration, the device output voltage switches to its high polarity when a north pole is the target feature nearest to the device. If the direction of rotation is reversed, then the output polarity inverts. Mechanical Position (Target moves past device pin 1 to pin 4) Target (Radial Ring Magnet) This pole sensed earlier Target (Ring Magnet) S N Target Magnetic Profile +B N S S N S This pole sensed later Element Pitch Hall Element 2 Hall Element 1 Hall IC (Pin 4 Side) -B Device Orientation to Target (Pin 1 Side) Figure 1. Relative motion of the target is detected by the dual Hall elements mounted on the Hall IC. Element Pitch Sensor Branded Face Hall Element 2 Hall Element 1 IC (Pin 4 Side) (Pin 1 Side) (View of Sensor Opposite Pins) Branded Face of L Package Rotating Target S N S N S NS Device Internal Differential Analog Signal, VPROC BOP(#1) N Pin 1 Pin 4 BRP(#1) Branded Face of K Package Rotating Target BRP(#2) Device Internal Switch State On Off On Off Device Output Signal, VOUT S N S N S NS Pin 1 N +t Pin 4 Figure 2. This left-to-right (pin 1 to pin 4) direction of target rotation results in a high output state when a north magnetic pole of the target is nearest the face of the device (see figure 3). A right-to-left (pin 4 to pin 1) rotation inverts the output signal polarity. Figure 3. The magnetic profile reflects the geometry of the target, allowing the A1667 to present an accurate digital output response. Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 7 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC state changes from low to high. As shown in figure 5, threshold levels for the A1667 switchpoints Switchpoints are the threshold levels of the differential internal are established as a function of the peak input signal levels. The analog signal, VPROC , at which the device changes output signal A1667 incorporates an algorithm that continuously monitors the state. The value of VPROC is directly proportional to the magnetic flux input signal and updates the switching thresholds accordingly with density, B, induced by the target and sensed by the Hall elements. As VPROC rises through a certain limit, referred to as the operate limited inward movement of VPROC. The switchpoint for each edge point, BOP , the output state changes from high to low. As VPROC is determined by the detection of the previous two signal edges. In falls below BOP to a certain limit, the release point, BRP , the output this manner, variations are tracked in real time. CONTINUOUS UPDATE OF SWITCHPOINTS (A) TEAG varying; cases such as eccentric mount, out-of-round region, normal operation position shift (B) Internal analog signal, VPROC, typically resulting in the IC V+ Smaller TEAG IC VPROC (V) Target Target Smaller TEAG Hysteresis Band (Delimited by switchpoints) Larger TEAG IC Smaller TEAG Larger TEAG 0 Target Rotation () 360 (C) Internal analog signal, VPROC, representing magnetic field for digital output V+ BOP VPROC (V) BOP BRP BRP BOP BOP BOP BRP BRP VOUT (V) BRP BOP Figure 4. The Continuous Update algorithm allows the Allegro IC to interpret and adapt to variances in the magnetic field generated by the target as a result of eccentric mounting of the target, out-of-round target shape, and similar dynamic application problems that affect the TEAG (Total Effective Air Gap). As shown in panel A, the variance in the target position results in a change in the TEAG. This affects the IC as a varying magnetic field, which results in proportional changes in the internal analog signal, VPROC, shown in panel B. The Continuous Update algorithm is used to establish switchpoints based on the fluctuation of VPROC, as shown in panel C. Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 8 A1667 +B True Zero-Speed, High Accuracy, Ring Magnet Sensor IC V+ PK(1) PK(9) PK(3) PK(7) VPROC (V) BSIG (G) PK(5) BOP(A) BOP(B) BHYS(A) BHYS(B) BRP(A) BOP(C) BOP(D) BHYS(D) BRP(C) BRP(B) PK(4) BHYS(C) BRP(D) PK(6) PK(2) PK(8) -B t+ Figure 5. The Continuous Update algorithm operation. Not detailed in the figure are the boundaries for peak capture DAC movement which intentionally limit the amount of inward signal variation the IC is able to react to over a single transition. The algorithm is used to establish and subsequently update the device switchpoints (BOP and BRP). The hysteresis, BHYS(#x) , at each target feature configuration results from this recalibration, ensuring that it remains properly proportioned and centered within the peak-to-peak range of the internal analog signal, VPROC. Magnetic Field Chart Index PK(1) Peak VPROC Amplitude Target Behavior (Example only) Peak Magnetic Signal, BPK TEAG small +BPK (South Polarity) VPROCPK(1) PK(2) TEAG small -BPK (North Polarity) VPROCPK(2) PK(3) TEAG mid +BPK (South Polarity) VPROCPK(3) PK(4) TEAG mid -BPK (North Polarity) VPROCPK(4) PK(5) TEAG large +BPK (South Polarity) VPROCPK(5) PK(6) TEAG large -BPK (North Polarity) VPROCPK(6) PK(7) TEAG mid +BPK (South Polarity) VPROCPK(7) PK(8) TEAG mid -BPK (North Polarity) VPROCPK(8) PK(9) TEAG small +BPK (South Polarity) VPROCPK(9) Centered Calculated Range, BHYS Operate Point. BOP Release Point. BRP (70% B(PKPK) (30% B(PKPK) 70% VPROC(PKPK)) 30% VPROC(PKPK)) BHYS (Previous state) BOP(A) A BRP(A) BOP(B) BRP(B) BOP(C) BRP(C) BOP(D) BRP(D) B C D (Next state) Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 9 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC START MODE HYSTERESIS This feature helps to ensure optimal self-calibration by rejecting electrical noise and low-amplitude target vibration during initialization. This prevents AGC from calibrating the IC on such spurious signals. Calibration can be performed using the actual target features. Target, Ring Magnet A typical scenario is shown in figure 6. The Start Mode Hysteresis, POHYS , is a minimum level of the peak-to-peak amplitude of the internal analog electrical signal, VPROC, that must be exceeded before the A1667 starts to compute switchpoints. S N S Target Magnetic Profile BOP(initial) Differential Signal, VPROC BRP Start Mode Hysteresis, POHYS BOP BRP(initial) IC Position Relative to Target Output Signal, VOUT 1 2 3 BOP 4 If exceed POHYS on high side If exceed POHYS on low side Figure 6. Operation of Start Mode Hysteresis * At power-on (position 1), the A1667 begins sampling VPROC. * At the point where the Start Mode Hysteresis, POHYS , is exceeded, the device establishes an initial switching threshold, by using the Continuous Update algorithm. If VPROC is falling through the limit on the low side (position 2), the switchpoint is BRP , and if VPROC is rising through the limit on the high side (position 4), it is BOP . After this point, Start Mode Hysteresis is no longer a consideration. Note that a valid VPROC value exceeding the Start Mode Hysteresis can be generated either by a legitimate target feature or by excessive vibration. * In either case, because the switchpoint is immediately passed as soon as it is established, the A1667 enables switching: --If on the low side, at BRP (position 2) the output would switch from low to high. However, because output is already high, no output switching occurs. At the next switchpoint, where BOP is passed (position 3), the output switches from high to low. --If on the high side, at BOP (position 4) the output switches from high to low. As this example demonstrates, initial output switching occurs with the same polarity, regardless of whether the Start Mode Hysteresis is exceeded on the high side or on the low side. Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 10 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC UNDERVOLTAGE LOCKOUT When the supply voltage falls below the undervoltage lockout voltage, VCC(UV) , the device enters Reset, where the output state returns to the Power-On State (POS) until sufficient VCC is supplied. ICC levels may not meet datasheet limits when VCC < VCC(min). This lockout feature prevents false signals, caused by undervoltage conditions, from propagating to the output of the IC. POWER SUPPLY PROTECTION The device contains an on-chip regulator and can operate over a wide VCC range. For devices that must operate from an unregulated power supply, transient protection must be added externally. For applications using a regulated line, EMI/RFI protection may still be required. Contact Allegro for information on the circuitry needed for compliance with various EMC specifications. Refer to figure 7 for an example of a basic application circuit. AUTOMATIC GAIN CONTROL (AGC) This feature allows the device to operate with an optimal internal electrical signal, regardless of the air gap (within the AG specification). At power-on, the device determines the peak-to-peak amplitude of the signal generated by the target. The gain of the IC is then automatically adjusted. Figure 8 illustrates the effect of this feature. AUTOMATIC OFFSET ADJUST (AOA) The AOA circuitry automatically compensates for the effects of chip, magnet, and installation offsets. This circuitry is continuously active, including during both power-on mode and running mode, compensating for any offset drift (within the Allowable User Induced Differential Offset). Continuous operation also allows it to compensate for offsets induced by temperature variations over time. RUNNING MODE LOCKOUT The A1667 has a running mode lockout feature to prevent switching in response to small signals that are characteristic of vibration signals. The internal logic of the chip considers small signal amplitudes below a certain level to be vibration. The output is held to the state prior to lockout until the amplitude of the signal returns to normal operational levels. Target Ring Magnet VPULLUP VCC A1667 1 CBYPASS 0.1 F (Optional) VCC VOUT RL 2 N S N S V+ Internal Differential Analog Signal Response, without AGC AGLarge AGSmall GND 4 TEST 3 CL V+ Internal Differential Analog Signal Response, with AGC Figure 7. Typical circuit for proper device operation. AGSmall AGLarge Figure 8. Automatic Gain Control (AGC). The AGC function corrects for variances in the air gap. Differences in the air gap cause differences in the magnetic field at the device, but AGC prevents that from affecting device performance, as shown in the lowest panel. Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 11 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC POWER DERATING The device must be operated below the maximum junction temperature of the device, TJ(max). Under certain combinations of peak conditions, reliable operation may require derating supplied power or improving the heat dissipation properties of the application. This section presents a procedure for correlating factors affecting operating TJ. (Thermal data is also available on the Allegro website.) The Package Thermal Resistance, RJA, is a figure of merit summarizing the ability of the application and the device to dissipate heat from the junction (die), through all paths to the ambient air. Its primary component is the Effective Thermal Conductivity, K, of the printed circuit board, including adjacent devices and traces. Radiation from the die through the device case, RJC, is relatively small component of RJA. Ambient air temperature, TA, and air motion are significant external factors, damped by overmolding. The effect of varying power levels (Power Dissipation, PD), can be estimated. The following formulas represent the fundamental relationships used to estimate TJ, at PD. PD = VIN x IIN (1) T = PD x RJA (2) (3) TJ = TA + T Example: Reliability for VCC at TA = 150C, package K, using a single-layer PCB. Observe the worst-case ratings for the device, specifically: RJA = 177C/W, TJ(max)= 165C, VCC(max) = 24 V, and ICC(max) = 12 mA. Calculate the maximum allowable power level, PD(max). First, invert equation 3: Tmax = TJ(max) - TA = 165 C - 150C = 15 C This provides the allowable increase to TJ resulting from internal power dissipation. Then, invert equation 2: PD(max) = Tmax / RJA = 15C / 177C/W = 84.7 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) /ICC(max) = 119 mW / 12 mA = 7.1 V The result indicates that, at TA, the application and device can dissipate adequate amounts of heat at voltages VCC(est). Compare VCC(est) to VCC(max). If VCC(est) VCC(max), then reliable operation between VCC(est) and VCC(max) requires enhanced RJA. If VCC(est) VCC(max), then operation between VCC(est) and VCC(max) is reliable under these conditions. For example, given common conditions such as: TA= 25C, VCC = 12 V, ICC = 7.5 mA, and RJA = 177C/W, then: PD = VCC x ICC = 12 V x 7.5 mA = 90 mW T = PD x RJA = 90 mW x 177C/W = 11.3C TJ = TA + T = 25C + 11.3C = 36.3C A worst-case estimate, PD(max), represents the maximum allowable power level (VCC(max), ICC(max)), without exceeding TJ(max), at a selected RJA and TA. Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 12 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC Package K, 4-Pin SIP +0.08 5.21 -0.05 B 45 E 2.20 E 1.55 0.05 1.50 D 1.32 E +0.08 3.43 -0.05 E2 E1 Branded Face 2.16 MAX 2 3 1 C Standard Branding Reference View 0.84 REF N = Device part number Y = Last two digits of year of manufacture W = Week of manufacture For Reference Only; not for tooling use (reference DWG-9010) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown 4 14.73 0.51 +0.06 0.38 -0.03 +0.07 0.41 -0.05 YYWW 45 A 1 NNNN Mold Ejector Pin Indent A Dambar removal protrusion (8x) B Gate and tie bar burr area C Branding scale and appearance at supplier discretion D Active Area Depth, 0.43 0.011 mm E Hall elements (E1 and E2); not to scale 1.27 NOM Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 13 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC Package L, 8-Pin SOIC For Reference Only - Not for Tooling Use (Reference DWG-0000385) Dimensions in millimeters - NOT TO SCALE Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown 4.90 BSC E 1.35 8 0 2.20 8 0.65 1.27 8 A 1.75 0.21 0.04 1.95 E 3.90 BSC E1 5.60 6.00 BSC E2 D 0.84 1 +0.43 -0.44 2 1 0.25 BSC 8x +0.13 1.62 -0.27 B 0.10 0.41 0.10 1.27 BSC 0.15 SEATING PLANE Active Area Depth, 0.40 mm NOM B Reference land pattern layout (reference IPC7351 SOIC127P600X175-8M); all pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances Branding scale and appearance at supplier discretion D Terminal #1 mark area E Hall elements (E1 and E2); not to scale B PCB Layout Reference View GAUGE PLANE +0.10 -0.05 A C B SEATING PLANE 2 NNNNNNN YYWW LLLL 1 C Standard Branding Reference View N Y W L = Device part number = Supplier emblem = Last two digits of year of manufacture = Week of manufacture = Lot number Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 14 A1667 True Zero-Speed, High Accuracy, Ring Magnet Sensor IC Revision History Number Date Description 1 May 13, 2016 Added L package option 2 April 4, 2017 Corrected K package active area depth 3 October 4, 2018 Corrected L package Hall element spacing; minor editorial updates Copyright (c)2018, Allegro MicroSystems, LLC Allegro MicroSystems, LLC reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. Allegro's products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro's product can reasonably be expected to cause bodily harm. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. Copies of this document are considered uncontrolled documents. For the latest version of this document, visit our website: www.allegromicro.com Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com 15