A3064 Hall Effect Gear Tooth Sensor IC, AC Coupled Discontinued Product These parts are no longer in production The device should not be purchased for new design applications. Samples are no longer available. Date of status change: October 31, 2005 Recommended Substitutions: For new customers and applications, refer to the A1421LK. NOTE: For detailed information on purchasing options, contact your local Allegro field applications engineer or sales representative. Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. Data Sheet 27612.21B 3064 HALL-EFFECT GEAR-TOOTH SENSOR IC —AC COUPLED X The A3064LKA ac-coupled Hall-effect gear-tooth sensor IC is a monolithic integrated circuit that switches in response to changing differential magnetic fields created by moving ferrous targets. This device is ideal for use in non-zero-speed, gear-tooth-based speed, position, and timing applications such as in anti-lock braking systems, transmissions, and crankshafts. X 2 3 4 OUTPUT GROUND FILTER 5 FILTER 1 SUPPLY VCC Dwg. PH-011-1 Pinning is shown viewed from branded side. ABSOLUTE MAXIMUM RATINGS at TA = +25°C Supply Voltage, VCC ............................. 24 V When coupled with a back-biasing magnet, the device can be configured to turn on or off with the leading or trailing edge of a geartooth or slot. Changes in fields on the magnet face caused by a moving ferrous mass affect the two Hall transducers and are differentially amplified by on-chip electronics. This differential design provides immunity to radial vibration within the device’s operating air gap. Steady-state magnet and system offsets are eliminated using an on-chip differential band-pass filter. This filter also provides relative immunity to interference from RF and electromagnetic sources. The on-chip temperature compensation and Schmitt trigger circuitry minimizes shifts in effective working air gaps and switch points over temperature, allowing operation to low frequencies over a wide range of air gaps and temperatures. Each Hall-effect digital Integrated circuit includes a voltage regulator, two quadratic Hall-effect elements, temperature compensating circuitry, a low-level amplifier, band-pass filter, Schmitt trigger, and an open-collector output driver. The on-board regulator permits operation with supply voltages of 4.5 to 24 volts. The output stage can easily switch 20 mA over the full frequency response range of the device and is compatible with bipolar and MOS logic circuits. The device is packaged in a 5-pin plastic SIP. FEATURES For Sensing Motion of Ferrous Targets Wide Operating Temperature Range Operation to 30 kHz Resistant to EMI Large Effective Air Gap 4.5 V to 24 V Operation Output Compatible With All Logic Families Reverse Battery Protection Resistant to Physical Stress Operating Temperature Range, TA ............................... -40°C to +150°C ■ ■ ■ ■ ■ ■ ■ ■ ■ Storage Temperature Range, TS ............................... -65°C to +170°C Always order by complete part number, e.g., A3064LKA . Reverse Battery Voltage, VRCC .......... -30 V Magnetic Flux Density, B ............ Unlimited Output Off Voltage, VOUT ...................... 24 V Output Current, IOUT ......................... 25 mA Package Power Dissipation, PD ............................................ 500 mW 3064 HALL-EFFECT GEAR-TOOTH SENSOR IC —AC COUPLED 1 SUPPLY FUNCTIONAL BLOCK DIAGRAM REG OUTPUT 2 + X 3 X GROUND 5 4 FILTER FILTER Dwg. FH-008-1 ELECTRICAL CHARACTERISTICS over operating temperature and supply voltage range. Limits Characteristic Symbol Supply Voltage VCC Output Saturation Voltage Test Conditions Operating Min. Typ. Max. Units 4.5 — 24 V VOUT(SAT) IOUT = 18 mA, B < BRP — 141 400 mV Output Leakage Current I OFF VOUT = 24 V, B > BOP — — 5.0 µA Supply Current ICC B < BRP — 11 20 mA B > BOP — 9.6 — mA -3 dB 30 — — kHz High-Frequency Cutoff fcoh Output Rise time tr VOUT = 12 V, RL = 820 Ω — 0.04 0.2 µs Output Fall time tf VOUT = 12 V, RL = 820 Ω — 0.18 0.3 µs MAGNETIC CHARACTERISTICS over operating temperature and supply voltage range. Limits Characteristic Symbol Operate Point BOP Release Point Hysteresis Test Conditions Min. Typ. Max. Units Output switches on to off 0 15 27.5 G BRP Output switches off to on -12.5 0 7.5 G Bhys BOP - BRP 5.0 15 35 G NOTES: 1. Magnetic switch points are specified as the difference in magnetic fields at the two Hall elements. 2. As used here, negative flux densities are defined as less than zero (algebraic convention). 3. Typical values are at T A = 25°C and VCC = 12 V. 4. 1 gauss (G) is exactly equal to 0.1 millitesla (mT). 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 2001 Allegro MicroSystems, Inc. 3064 HALL-EFFECT GEAR-TOOTH SENSOR IC —AC COUPLED TYPICAL OPERATING CHARACTERISTICS SWITCH POINTS 30 DIFFERENTIAL FLUX DENSITY IN GAUSS V = 12 V CC 20 OPERATE POINT 10 0 -10 RELEASE POINT -50 -25 0 25 75 50 100 125 150 AMBIENT TEMPERATURE IN °C Dwg. GH-056-1 OUTPUT SATURATION VOLTAGE 200 I OUT = 18 mA I OUT = 18 mA V CC = 12 V TA= +25°C SATURATION VOLTAGE IN mV SATURATION VOLTAGE IN mV 300 200 100 0 -50 -25 0 25 50 75 100 125 150 AMBIENT TEMPERATURE IN °C 100 50 0 5 10 15 20 25 SUPPLY VOLTAGE IN VOLTS Dwg. GH-029-6 www.allegromicro.com 150 Dwg. GH-055-2 3 3064 HALL-EFFECT GEAR-TOOTH SENSOR IC —AC COUPLED TYPICAL OPERATING CHARACTERISTICS SUPPLY CURRENT 20 20 VCC = 24 V 15 SUPPLY CURRENT IN mA SUPPLY CURRENT IN mA 15 B < B RP 10 B > B OP 5 B < B RP 10 B > B OP 5 TA = +25°C 0 -50 -25 0 25 50 75 100 125 0 150 0 5 10 15 20 25 SUPPLY VOLTAGE IN VOLTS AMBIENT TEMPERATURE IN °C Dwg. GH-031-3 Dwg. GH-028-9 APPLICATIONS INFORMATION The A3064LKA is a versatile high-precision differential sensing device that can be used in a wide range of applications. Careful choice of the sensor IC, target material and shape, magnet material and shape, and assembly techniques enables large working air gaps and high switch-point accuracy over the system operating temperature range. The devices can be used without a back-biasing magnet. For example, the device can be used to detect a rotating ring magnet such as those found in brushless dc motors or in speed sensing applications. Device Operation. These sensor ICs each contain two Hall transducers (E1 and E2) that are used to sense a magnetic field differential across the face of the IC (see Element Location drawing). Referring to the Typical Transfer Characteristic (Figure 1), the trigger switches the output off (output high) when BE1 - BE2 > BOP and switches the output on (output 4 +V V CC OUTPUT VOLTAGE Magnet Biasing. To sense moving non-magnetized ferrous targets, these devices must be back biased by mounting the unbranded side on a small permanent magnet. Either magnetic pole (north or south) can be used. Figure 1 TYPICAL TRANSFER CHARACTERISTIC B RP BOP VOUT(SAT) 0 -B 0 +B FLUX DENSITY 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Dwg. GH-007-6 3064 HALL-EFFECT GEAR-TOOTH SENSOR IC —AC COUPLED APPLICATIONS INFORMATION (cont’d) Figure 2 low) when BE1 - BE2 < BRP. The difference between BOP and BRP is the hysteresis of the device. LEADING EDGE Note that powering up in the absence of a differential magnetic field (less than the device BOP and higher than the device BRP) will allow an indeterminate output state. The correct output state is warranted after the first excursion beyond BOP or BRP. AC-Coupled Operation. Steady-state magnet and system offsets are eliminated using an on-chip differential bandpass filter. The lower frequency cut-off of this patented filter is set using an external capacitor, the value of which can range from 0.01 µF to 10 µF. The high-frequency cut-off of this filter is set at 30 kHz by an internal integrated capacitor. The differential structure of this filter improves the ability of the IC to reject single-ended noise on the ground or supply line and, as a result, makes it more resistant to radio-frequency and electromagnetic interference typically seen in hostile remote-sensing environments. This filter configuration also increases system tolerance to capacitor degradation at high temperatures, allowing the use of an inexpensive external ceramic capacitor. Low-Frequency Operation. Low-frequency operation of the device is set by the value of an external capacitor. Ideally, the differential flux density range (determined by the applied target) vs. air gap assumes a perfect sinusoidal input. Figure 3 provides the low-frequency cut-off (-3 dB point) of the filter as a function of capacitance value. This information should be used with care. In reality, when used with gear teeth, GEAR DIRECTION OF ROTATION E2 E1 NORTH SOUTH 4300 G (a) B &B E1 E2 4150 G 150 G BOP= +15 G B –B E1 (b) 0G E2 B RP= 0 G -150 G V OUT (c) V OUT(SAT) OUTPUT DUTY CYCLE ≈ 50% Dwg. WH-003-3 Figure 3 1k LOW-FREQUENCY CUTOFF IN Hz Figure 2 relates the output state of a back-biased sensor IC, with switching characteristics shown in Figure 1, to the target gear profile and position. Assume a north pole back-bias configuration (equivalent to a south pole at the face of the device). The motion of the gear produces a phase-shifted field at E1 and E2 (Figure 2(a)); internal conditioning circuitry subtracts the fields at the two elements (Figure 2(b)); this differential field is band-pass filtered to remove dc offset components and then fed into a Schmitt trigger; the Schmitt trigger switches the output transistor at the thresholds BOP and BRP. As shown (Figure 2(c)), the IC output is low whenever E2 faces a (ferrous) gear tooth and element E1 faces air. The output is high when element E1 faces air and E2 faces a ferrous target. TRAILING EDGE 100 10 1.0 0.1 0.01 0.1 1.0 10 CAPACITANCE IN µF Dwg. GH-025 www.allegromicro.com 5 3064 HALL-EFFECT GEAR-TOOTH SENSOR IC —AC COUPLED APPLICATIONS INFORMATION (cont’d) the teeth create transitions in the magnetic field that have a much higher frequency content than the basic rotational speed of the target. This allows the device to work with speeds much lower than those indicated by the graph for a given capacitor value. Capacitor Characteristics. The major requirement for the external capacitor is its ability to operate in a bipolar (nonpolarized) mode. Another important requirement is the low leakage current of the capacitor (equivalent parallel resistance should be greater than 500 kΩ). To maintain proper operation with frequency, capacitor values should be held to within ±30% over the operating temperature range. The commonly available Z5U ceramic capacitor temperature code should not be used in this application. Magnet Selection. The A3064LKA can be used with a wide variety of commercially available permanent magnets. The selection of the magnet depends on the operational and environmental requirements of the sensing system. For systems that require high accuracy and large working air gaps or an extended temperature range, the usual magnet material of choice is rare-earth samarium cobalt (SmCo). This magnet material has a high energy product and can operate over an extended temperature range. For systems that require low-cost solutions for an extended temperature range, AlNiCo 8 can be used. Due to its relatively low energy product, smaller operational air gaps can be expected. Neodymium iron boron (NeFeB) can be used over moderate temperature ranges when large working air gaps are required. Of these three magnet materials, AlNiCo 8 is the least expensive by volume and SmCo is the most expensive. Extensive applications information for Hall-effect devices is available in: • Hall-Effect IC Applications Guide, Application Note 27701; • Hall-Effect Devices: Soldering, Gluing, Potting, Encapsulating, and Lead Forming, Application Note 27703.1; • Soldering of Through-Hole Hall-Sensor Dervices, Application Note 27703; and • Soldering of Surface-Mount Hall-Sensor Devices, Application Note 27703.2. All are provided in Allegro Electronic Data Book, AMS-702. or at Figure 4 ELEMENT LOCATIONS (±0.005 [0.13 mm] die placement) ACTIVE AREA DEPTH 0.0165" 0.42 mm NOM 0.087" 2.20 mm 0.075" 1.91 mm E1 E2 A BRANDED SURFACE 1 2 3 4 5 Dwg. MH-007E Allegro www.allegromicro.com 6 0.083" 2.10 mm 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 3064 HALL-EFFECT GEAR-TOOTH SENSOR IC —AC COUPLED CRITERIA FOR DEVICE QUALIFICATION All Allegro devices are subjected to stringent qualification requirements prior to being released to production. To become qualified, except for the destructive ESD tests, no failures are permitted. Qualification Test Test Method and Test Conditions Test Length Samples Biased Humidity (HAST) JESD22-A101, RH = 85% 2000 hrs 320 VCC = VOUT = 12 V 116 pcs at TA = 25°C 116 pcs at TA = 150°C High-Temperature Operating Life (HTOL) JESD22-A108, TJ ≤ 190°C 2000 hrs 146 VCC = VOUT = 12 V 116 pcs at TA = 25°C 30 pcs at TA = 150°C Accelerated HTOL TA = 175°C, TJ ≤ 190°C 500 hrs 50 VCC = VOUT = 7.5 V Autoclave, Unbiased JESD22-A102, Condition C, TA = 121°C at 15 psig 192 hrs 77 Solder Heat Comments 22 High-Temperature (Bake) Storage Life MIL-STD-883, Method 1008, TA = 170°C 2000 hrs 77 Temperature Cycle (unbiased) MIL-STD-883, Method 1010, +25°C to +150°C 2000 cycles 153 ESD, Human Body Model MIL-STD-883, Method 3015 Pre/Post Reading 3 per test Test to failure, All leads > 2 kV The products described herein are manufactured under one or more of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283; 5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719; 5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents pending. Allegro MicroSystems, Inc. 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 products are not authorized for use as critical components in life-support appliances, devices, or systems without express written approval. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties that may result from its use. www.allegromicro.com 7 3064 HALL-EFFECT GEAR-TOOTH SENSOR IC —AC COUPLED Dimensions in Inches Dimensions in Millimeters (controlling dimensions) (for reference only) 0.252 0.247 6.40 6.27 0.063 0.059 1.60 1.50 0.181 0.176 4.60 4.47 45° 0.083 MAX 1 2 3 4 45° 0.018 5 2.11 MAX 0.0173 0.0138 0.600 0.560 SEE NOTE 1 2 3 4 0.46 5 0.44 0.35 15.24 14.23 SEE NOTE 0.0189 0.0142 0.050 BSC Dwg. MH-010H in 0.48 0.36 1.27 BSC Dwg. MH-010H mm Horizontal-Mount Lead Form (order A3064LKA-TL) 2.41 0.095 ±0.13 ±0.005 0.051 0.002 MAX MAX 0.004 0°–8° MAX NOTES: 8 0.10 0.020 MIN FLAT 0°–8° MAX Dwg. MH-015 in 0.51 MIN FLAT 1. Tolerances on package height and width represent allowable mold offsets. Dimensions given are measured at the widest point (parting line). 2. Exact body and lead configuration at vendor s option within limits shown. 3. Height does not include mold gate flash. 4. Recommended minimum PWB hole diameter to clear transition area is 0.035 (0.89 mm). 5. Where no tolerance is specified, dimension is nominal. 6. Supplied in bulk pack (500 pieces per bag). 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Dwg. MH-015 mm