HALL-EFFECT SWITCH FOR 2-WIRE APPLICATIONS

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Paula Garrett
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1 Data Sheet A 3161 X This Hall-effect switch is a monolithic integrated circuit designed to operate continuously over extended temperatures to +85 C. The unipolar switching characteristic makes this device ideal for use with a simple bar or rod magnet. The A3161ELT and A3161EUA are identical except for package. V CC Each device includes a voltage regulator for operation with supply voltages of 3.5 to 25 volts, reverse battery protection diode, quadratic Hall-voltage generator, temperature compensation circuitry, small-signal amplifier, Schmitt trigger, and a constant-current open-collector output. Noise radiation is limited by control of the output current slew rate Two package styles provide a magnetically optimized package for most applications. Suffix LT is a miniature SOT-89/TO-243AA transistor package for surface-mount applications; suffix UA is a threelead ultra-mini SIP for through-hole mounting. SUPPLY GROUND OUTPUT Dwg. PH-3-3 Pinning is shown viewed from branded side. ABSOLUTE MAXIMUM RATINGS at T A = +25 C Supply Voltage, V CC Continuous V Surge (t w 1 ms)... 4 V Reverse Battery Voltage, V RCC Continuous V Surge (t w 1 ms) V Magnetic Flux Density, B... Unlimited Output OFF Voltage, V OUT V Operating Temperature Range, T A C to +85 C Storage Temperature Range, T S C to +17 C FEATURES and BENEFITS Internal Current Regulator for 2-Wire Operation Output Slew Rate Controlled 3.5 V to 25 V Operation Needs Only An Unregulated Supply Reverse Battery Protection Excellent Temp. Stability Activate with Small, Commercially Available Permanent Magnets Small Size Solid-State Reliability No Moving Parts Resistant to Physical Stress Always order by complete part number, e.g., A3161ELT.

2 ELECTRICAL CHARACTERISTICS over operating voltage and temperature ranges. Limits Characteristic Symbol Test Conditions Min. Typ. Max. Units Supply Voltage V CC Operating V Load Current I OUT + I CC 3.5 V V OUT < 12 V, B < B RP ma (2-wire application) V OUT 12 V, B < B RP ma B > B OP ma Output Current I OUT B < B RP 12 ma I OFF V OUT = 24 V, B > B OP <1. 1 µa Output Saturation Voltage V OUT I OUT = 5 ma, B < B RP V Output Slew Rate di/dt C L = 2 pf 7. 2 ma/µs Output Settling Time t sd C L = 2 pf 2 µs MAGNETIC CHARACTERISTICS over operating supply voltage range. Limits At T A = +25 C Over Oper. Temp. Range Characteristic Symbol Min. Typ. Max. Min. Typ. Max. Units Operate Point (output turns OFF) B OP G Release Point (output turns ON) B RP G Hysteresis (B OP - B RP ) B hys G NOTE:Typical values are at T A = +25 C and V CC = 12 V. FUNCTIONAL BLOCK DIAGRAM 1 V CC 3 OUTPUT REG. X 2 GROUND Dwg. FH Northeast Cutoff, Box 1536 Worcester, Massachusetts (58) Copyright 1998, 1999, Allegro MicroSystems, Inc.

3 TYPICAL OPERATING CHARACTERISTICS SWITCH POINTS TOTAL SUPPLY CURRENT 2 2 SWITCH POINT in GAUSS OPERATE POINT RELEASE POINT OVER OPER. VOLT. RANGE TOTAL SUPPLY CURRENT (IOUT + ICC) in ma VCC = 25 V VCC = 3.5 V VCC = 25 V VCC = 3.5 V B < BRP B > BOP AMBIENT TEMPERATURE in C Dwg. GH-44-1 AMBIENT TEMPERATURE in C Dwg. GH-28-4 OUTPUT SATURATION VOLTAGE SAFE OPERATING AREA 12 3 SATURATION VOLTAGE in mv IOUT = 5 ma VCC = 1 V MAXIMUM CONTINUOUS SUPPLY VOLTAGE in VOLTS PACKAGE SUFFIX CODE -LT PACKAGE SUFFIX CODE -UA AMBIENT TEMPERATURE in C Dwg. GH-29-3 AMBIENT TEMPERATURE in C Dwg. GH-68

4 SENSOR LOCATIONS ACTIVE AREA DEPTH.3".76 mm NOM Suffix LT A.85" 2.16 mm.45" 1.14 mm OPERATION The output of these devices (pin 3) switches OFF when the magnetic field at the Hall sensor exceeds the operate point threshold (B OP ). When the magnetic field is reduced to below the release point threshold (B RP ), the device output switches ON. The difference in the magnetic operate and release points is called the hysteresis (B hys ) of the device. This built-in hysteresis allows clean switching of the output even in the presence of external mechanical vibration and electrical noise BOP ACTIVE AREA DEPTH.18".46 mm NOM Suffix UA.78" 1.98 mm Dwg. MH-8-7 OUTPUT CURRENT in ma TA = +25 C 3. BRANDED SURFACE A.54" 1.36 mm Dwg. MH APPLICATIONS INFORMATION These devices are normally operated in a 2-wire mode, where the supply terminal and the output terminal are tied together. An external comparator detects the change in total supply current by the addition (output ON, B > B OP ) or subtraction (output OFF, B < B RP ) of I OUT. Hall effect applications information is available in the Hall-Effect IC Applications Guide, which can be found in the latest issue of the Allegro MicroSystems Electronic Data Book, AMS-72 or Application Note 2771, or at BRP MAGNETIC FLUX DENSITY in GAUSS Dwg. GH-7-1 TYPICAL 2-WIRE APPLICATION SUPPLY Icc + IoUT 3.1 µf.85 V 2 + X V CC 1 1 Ω Dwg. EH-11A 115 Northeast Cutoff, Box 1536 Worcester, Massachusetts (58) 853-5

5 PACKAGE DESIGNATOR LT Dimensions in Inches (for reference only) Dwg. MA-9-3A in Dimensions in Millimeters (controlling dimensions) Dwg. MA-9-3A mm

6 PACKAGE DESIGNATOR UA Dimensions in Inches (controlling dimensions) Dimensions in Millimeters (for reference only) MAX MAX SEE NOTE SEE NOTE Dwg. MH-14E in 1.27 Dwg. MH-14E mm NOTES: 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. 115 Northeast Cutoff, Box 1536 Worcester, Massachusetts (58) 853-5

7 The products described herein are manufactured under one or more of the following U.S. patents: 5,45,92; 5,264,783; 5,442,283; 5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,65,719; 5,686,894; 5,694,38; 5,729,13; 5,917,32; 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.

8 HALL-EFFECT SENSORS Partial Part Avail. Oper. Characteristics at T A = +25 C Number Temp. B OP(max) B RP(min) B hys(typ) Features Notes HALL-EFFECT UNIPOLAR SWITCHES in order of B OP and B hys 324 E/L chopper stabilized E ±6 ± micropower, chopper stabilized 3361 E +5* * 2-wire, chopper stabilized 3362 E * 2-wire, chopper stabilized 3161 E wire 3141 E/L S * output * output E ma output 1, E/L E/L E/L E/L E/L E/L J +4 to programmable, chopper stabilized 1 HALL-EFFECT LATCHES & BIPOLAR SWITCHES in order of B OP and B hys 326 E/L bipolar, chopper stabilized 328 E/L chopper stabilized 3134 E/L bipolar switch 3133 K/L/S bipolar switch 3281 E/L chopper stabilized 3132 K/L/S bipolar switch 3187 E/L * 3177 S S ma outputs 1, 3, S ma outputs 1, 3, E/L , L S E/L * 3283 E/L chopper stabilized 3189 E/L * 3275 S * E/L * Operating Temperature Ranges: S = -2 C to +85 C, E = -4 C to +85 C, J = -4 C to +115 C, K = -4 C to +125 C, L = -4 C to +15 C Notes 1. Protected. 2. Output 1 switches on south pole, output 2 switches on north pole for 2-phase, bifilar-wound, unipolar-driven brushless dc motor control. 3. Power driver output. 4. Active pull down. 5. Complementary outputs for 2-phase bifilar-wound, unipolar-driven brushless dc motor control. * Minimum. Maximum Latches will not switch on removal of magnetic field; bipolar switches may switch on removal of field but require field reversal for reliable operation over operating temperature range. 115 Northeast Cutoff, Box 1536 Worcester, Massachusetts (58) 853-5

3185 THRU 3189 HALL-EFFECT LATCHES FOR HIGH-TEMPERATURE OPERATION FEATURES. ABSOLUTE MAXIMUM RATINGS at T A = +25 C V CC GROUND OUTPUT SUPPLY

3185 THRU 3189 HALL-EFFECT LATCHES FOR HIGH-TEMPERATURE OPERATION FEATURES. ABSOLUTE MAXIMUM RATINGS at T A = +25 C V CC GROUND OUTPUT SUPPLY 3185 THRU 3189 Data Sheet 2769.2A X V CC These Hall-effect latches are extremely temperature-stable and stressresistant sensors especially suited for operation over extended temperature ranges to +15 C.