A3211 and A3212 Micropower, Ultra-sensitive Hall-effect Switches Features and Benefits Description ▪ ▪ ▪ ▪ The A 3211 and A3212 integrated circuits are ultra-sensitive, pole independent Hall-effect switches with latched digital output. These sensors are especially suited for operation in battery-operated, hand-held equipment such as cellular and cordless telephones, pagers, and palmtop computers. A 2.5 volt to 3.5 volt operation and a unique clocking scheme reduce the average operating power requirements to less than 15 μW with a 2.75 volt supply. ▪ ▪ ▪ ▪ Micropower operation Operation with north or south pole 2.5 to 3.5 V battery operation Chopper stabilized ▫ Superior temperature stability ▫ Extremely low switchpoint drift ▫ Insensitive to physical stress High ESD protection Solid-state reliability Small size Easily manufacturable with magnet pole independence Packages: Improved stability is made possible through chopper stabilization (dynamic offset cancellation), which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress. DFN/MLPD (EL) DFN/MLPD (EH) Unlike other Hall-effect switches, either a north or south pole of sufficient strength will turn the output on in the A3212, and in the absence of a magnetic field, the output is off. The A3211 provides an inverted output. The polarity independence and minimal power requirements allow these devices to easily replace reed switches for superior reliability and ease of manufacturing, while eliminating the requirement for signal conditioning. SIP (UA) SOT23W (LH) Continued on the next page… Not to scale Functional Block Diagram SUPPLY SWITCH LATCH OUTPUT SAMPLE & HOLD X DYNAMIC OFFSET CANCELLATION TIMING LOGIC GROUND Dwg. FH-020-5 3211-DS, Rev. 3 Conceptual Data Sheet Subject to Change Without Notice March 24, 2006 Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 Description (continued) This device includes on a single silicon chip a Hall-voltage generator, small-signal amplifier, chopper stabilization, a latch, and a MOSFET output. Advanced BiCMOS processing is used to take advantage of low-voltage and low-power requirements, component matching, very low input-offset errors, and small component geometries. Four package styles provide magnetically op ti mized solutions for most ap pli ca tions. Miniature lowprofile surface-mount package types EH and EL (0.75 and 0.50 mm nominal height) are leadless, LH is a leaded lowprofile SMD, and UA is a three-lead SIP for through-hole mounting. Packages are available in lead (Pb) free versions (suffix, –T) with 100% matte tin plated leadframe. EL package for limited release, engineering samples available. Selection Guide Ambient Temperature TA (°C) Pb-free1 Packing2 (Units/Pack) A3211EEHLT–T Yes Tape and Reel (3000) A3211EELLT–T Yes Tape and Reel (3000) A3211ELHLT–T Yes Tape and Reel (3000) A3212EEHLT–T Yes Tape and Reel (3000) A3212EELLT–T Yes Tape and Reel (3000) A3212ELHLT–T Yes Tape and Reel (3000) 3-Pin Surface Mount A3212EUA–T Yes Bulk Pack (500) SIP-3 Through Hole, Straight Lead A3212LLHLT–T Yes Tape and Reel (3000) 3-Pin Surface Mount A3212LUA–T Yes Bulk Pack (500) SIP-3 Through Hole, Straight Lead Part Number Package Leadless Surface Mount –40 to 85 3-Pin Surface Mount Leadless Surface Mount –40 to 85 –40 to 150 1Pb-based variants are being phased out of the product line. Certain variants cited in this footnote are in production but have been determined to be NOT FOR NEW DESIGN. This classification indicates that sale of this device is currently restricted to existing customer applications. The variants should not be purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available. Status change: May 1, 2006 for A3212EEHLT and A3212EUA, and October 31, 2005 for A3212LLHLT and A3212LUA. 2Contact Allegro for additional packaging and handling options. Absolute Maximum Ratings Characteristic Supply Voltage Magnetic Flux Density Symbol Rating Units VDD Notes 5 V B Unlimited G Output Off Voltage VOUT 5 V Output Current IOUT 1 mA Range E –40 to 85 ºC Range L Operating Ambient Temperature TA –40 to 150 ºC Maximum Junction Temperature TJ(max) 165 ºC Tstg –65 to 170 ºC Storage Temperature Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 2 Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 6 5 4 Dwg. PH-016-2 GROUND (Leadless Chip Carrier) NO CONNECTION Package Suffix ‘EL’ Pinning (Leadless Chip Carrier) SUPPLY Package Suffix ‘EH’ Pinning 3 X VDD V 2 3 OUTPUT NO CONNECTION GROUND DD 1 2 OUTPUT GROUND SUPPLY 1 Dwg. PH-016-1 Package Suffix ‘LH’ Pinning Package Suffix ‘UA’ Pinning (SOT23W) (SIP) X 3 V DD V Dwg. PH-016-1 2 3 OUTPUT 1 GROUND OUTPUT 2 GROUND SUPPLY 1 SUPPLY DD Dwg. PH-016 Pinning is shown viewed from branded side. Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 3 Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 ELECTRICAL CHARACTERISTICS over operating voltage and temperature range (unless otherwise specified). Characteristic Symbol Test Conditions Limits Min. Typ.* Max. Units Supply Voltage Range VDD Operating 2.5 2.75 3.5 V Output Leakage Current IOFF VOUT = 3.5 V, Output off – <1.0 1.0 μA Output On Voltage VOUT IOUT = 1 mA, VDD = 2.75 V – 100 300 mV Awake Time tawake – 45 90 μs Period tperiod – 45 90 ms d.c. – 0.1 – % Duty Cycle Chopping Frequency Supply Current – 340 – kHz IDD(EN) fC Chip awake (enabled) – – 2.0 mA IDD(DIS) Chip asleep (disabled) – – 8.0 μA VDD = 2.75 V – 5.1 10 μA – 6.7 10 μA IDD(AVG) VDD = 3.5 V * Typical data is at TA = 25°C and VDD = 2.75 V, and is for design information only. Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 4 Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 3211 MAGNETIC CHARACTERISTICS over operating voltage and temperature range (unless otherwise specified) Characteristic Operate Points Release Points Hysteresis Limits Symbol Test Conditions Min. Typ. Max. Units BOPS South pole to branded side; B > BOP, VOUT = High (Output Off) – 37 55 G BOPN North pole to branded side; B > BOP, VOUT = High (Output Off) –55 –40 – G BRPS South pole to branded side; B < BRP, VOUT = Low (Output On) 10 31 – G BRPN North pole to branded side; B < BRP, VOUT = Low (Output On) – –34 –10 G BHYS |BOPx - BRPx| – 5.9 – G NOTES: 1. Negative flux densities are defined as less than zero (algebraic convention), i.e., -50 G is less than +10 G. 2. BOPx = operate point (output turns off); BRPx = release point (output turns on). 3. Typical Data is at TA = +25°C and VDD = 2.75 V and is for design information only. 4. 1 gauss (G) is exactly equal to 0.1 millitesla (mT). 3212 MAGNETIC CHARACTERISTICS over operating voltage and temperature range (unless otherwise specified) Characteristic Operate Points Release Points Hysteresis Symbol Test Conditions BOPS Limits Min. Typ. Max. Units South pole to branded side; B > BOP, VOUT = Low (Output On) – 37 55 G BOPN North pole to branded side; B > BOP, VOUT = Low (Output On) –55 –40 – G BRPS South pole to branded side; B < BRP, VOUT = High (Output Off) 10 31 – G BRPN North pole to branded side; B < BRP, VOUT = High (Output Off) – –34 –10 G BHYS |BOPx - BRPx| – 5.9 – G NOTES: 1. Negative flux densities are defined as less than zero (algebraic convention), i.e., -50 G is less than +10 G. 2. BOPx = operate point (output turns on); BRPx = release point (output turns off). 3. Typical Data is at TA = +25°C and VDD = 2.75 V and is for design information only. 4. 1 gauss (G) is exactly equal to 0.1 millitesla (mT). Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 5 Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 TYPICAL OPERATING CHARACTERISTICS SWITCH POINTS 60 60 BOPS BOPS 40 SWITCH POINTS IN GAUSS SWITCH POINTS IN GAUSS 40 BRPS 20 VDD = 2.75 V 0 -20 BRPN -40 BRPS 20 TA = 25°C 0 -20 BRPN -40 BOPN BOPN -60 -50 -25 0 25 50 75 100 AMBIENT TEMPERATURE IN ° C 125 -60 2.4 150 2.6 2.8 3.0 3.2 3.4 SUPPLY VOLTAGE IN VOLTS Dwg. GH-027-3 3.6 Dwg. GH-057-2 SUPPLY CURRENT 7.0 AVERAGE SUPPLY CURRENT IN μA AVERAGE SUPPLY CURRENT IN μA 7.0 6.0 VDD =3.5 V VDD =2.75 V 5.0 VDD =2.5 V 4.0 3.0 -50 -25 0 25 50 75 AMBIENT TEMPERATURE IN °C 100 125 150 Dwg. GH-028-11 6.0 5.0 4.0 3.0 2.4 TA = 25°C 2.6 2.8 3.0 3.2 SUPPLY VOLTAGE IN VOLTS 3.4 3.6 Dwg. GH-058-7 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 6 Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 FUNCTIONAL DESCRIPTION Low Average Power. Internal timing circuitry activates the sensor for 45 μs and deactivates it for the remainder of the period (45 ms). A short "awake" time allows for stabilization prior to the sensor sampling and data latching on the falling edge of the timing pulse. The output during the "sleep" time is latched in the last sampled state. The supply current is not affected by the output state. B +V PERIOD IDD(EN) "AWAKE" — "SLEEP" SAMPLE & OUTPUT LATCHED HALL VOLTAGE IDD(DIS) 0 + Dwg. WH-017-2 Dwg. AH-011-2 More detailed descriptions of the circuit operation can be found in: Technical Paper STP 97-10, Monolithic Magnetic Hall Sensor Using Dynamic Quadrature Offset Cancellation and Technical Paper STP 99-1, Chopper-Stabilized Amplifiers With A Trackand-Hold Signal Demodulator. +V SAMPLE & HOLD Chopper-Stabilized Technique. The Hall element can be considered as a resistor array similar to a Wheatstone bridge. A large portion of the offset is a result of the mismatching of these resistors. These devices use a proprietary dynamic offset cancellation technique, with an internal high-frequency clock to reduce the residual offset voltage of the Hall element that is normally caused by device overmolding, temperature dependencies, and thermal stress. The chopper-stabilizing technique cancels the mismatching of the resistor circuit by changing the direction of the current flowing through the Hall plate using CMOS switches and Hall voltage measurement taps, while maintaing the Hallvoltage signal that is induced by the external magnetic flux. The signal is then captured by a sample-and-hold circuit and further processed using low-offset bipolar circuitry. This technique produces devices that have an extremely stable quiescent Hall output voltage, are immune to thermal stress, and have precise recoverability after temperature cycling. A relatively high sampling frequency is used for faster signal processing capability can be processed. X Dwg. EH-012-1 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 7 Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 FUNCTIONAL DESCRIPTION (cont'd) A3211 OUTPUT VOLTAGE B OPN 0 -B +B MAGNETIC FLUX A3212 OUTPUT OFF 5V MAX B OPS OUTPUT VOLTAGE B OPN OUTPUT ON BRPS BRPN OUTPUT ON 0 0 -B +B MAGNETIC FLUX S UP P LY (3 V B AT T E R Y ) 1 DD 3 50 k 2 OUT P UT V www.allegromicro.com B OPS OUTPUT ON 0 Applications. Allegro's pole-independent sensing technique allows for operation with either a north pole or south pole magnet orientation, enhancing the manufacturability of the device. The state-of-the-art technology provides the same output polarity for either pole face. The simplest form of magnet that will operate these devices is a bar magnet with either pole near the branded surface of the device. Many other methods of operation are possible. Extensive applications information for Hall-effect sensors 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 at B RPS BRPN As used here, negative flux densities are defined as less than zero (algebraic convention), i.e., -50 G is less than +10 G. It is strongly recommended that an external bypass capacitor be connected (in close proximity to the Hall sensor) between the supply and ground of the device to reduce both external noise and noise generated by the chopper-stabilization technique. This is especially true due to the relatively high impedance of battery supplies. OUTPUT OFF OUTPUT OFF 5V MAX X Operation. The output of the A3212 switches low (turns on) when a magnetic field perpendicular to the Hall sensor exceeds the operate point BOPS (or is less than BOPN). After turn-on, the output is capable of sinking up to 1 mA and the output voltage is VOUT(ON). When the magnetic field is reduced below the release point BRPS (or increased above BRPN), the device output switches high (turns off). The difference in the magnetic operate and release points is the hysteresis (Bhys) of the device. This built-in hysteresis allows clean switching of the output even in the presence of external mechanical vibration and electrical noise. The A3211 functions in the same manner, except the output voltage is reversed from the A3212, as shown in the figures to the right. 0.1 ∝F Dwg. E H-013-2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 8 Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 SENSOR LOCATIONS Package Designator 'EL' Package Designator 'EH' ACTIVE AREA DEPTH 0.013" 0.34 mm NOM ACTIVE AREA DEPTH 0.006" 0.16 mm NOM 0.035" 0.88 mm 6 5 .0406 1.03 mm 3 4 .0291 0.74 mm 0.062" 1.56 mm BRANDED SURFACE BRANDED SURFACE A 1 1 3 2 A 2 Dwg. MH-030 Package Designator 'UA' Package Designator 'LH' ACTIVE AREA DEPTH 0.011" 0.28 mm NOM ACTIVE AREA DEPTH 0.0195" 0.50 mm NOM 0.056" 1.42 mm 3 0.078" 1.98 mm 0.033" 0.84 mm 0.052" 1.32 mm A A 1 2 Dwg. MH-025-2 BRANDED SURFACE 1 2 3 Dwg. MH-011-13 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 9 Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 PACKAGE DESIGNATOR ‘EH' (Reference MO-229C WCED-1) 2.15 .085 1.85 .073 6 3.15 .124 2.85 .112 A 1 0.30 .012 0.20 .008 0.50 .020 BSC 0.30 .012 BSC 0.80 .031 0.70 .028 0.50 .020 BSC 0.20 .008 REF 6 0.05 .002 0.00 .000 1 1.00 .039 BSC 0.65 .026 0.45 .018 C 3.70 .146 BSC 1.25 .049 BSC 1.324 .052 1.074 .042 0.25 .010 BSC B 6 1 0.25 .010 BSC 0.40 .016 BSC 1.142 .045 0.892 .035 Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only A Pin index area B Exposed thermal pad C ø0.3 Thermal via (optional) 0.95 .037 BSC 10 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 PACKAGE DESIGNATOR ‘EL' MLPD 3 Contact 2.00 .079 BSC 3 2.00 .079 BSC A 1 0.32 .013 0.20 .008 1.350 .053 BSC 0.32 .013 MIN 0.50 .020 0.30 .012 3 0.15 .006 REF 0.05 0.80 .002 .031 0.00 0.70 .000 .028 1 2 0.138 .005 REF D 0.20 .008 REF C 0.138 .005 REF 1 0.50 .020 BSC 1.025 .040 0.775 .031 B 1.350 .053 1.100 .043 Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only A Pin index area B Exposed thermal pad C Optional thermal vias, ∅0.30 [.012], pitch 1.2 [.047] R0.200 .008 REF 2.40 .094 REF 0.15 .006 MIN 0.40 .016 NOM 0.55 .022 0.45 .018 0.50 .020 BSC 0.325 .013 REF 1.025 .040 MAX 2 3 D Typical pad layout; adjust as necessary to meet application process requirements 0.325 .013 REF 11 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 PACKAGE DESIGNATOR ‘LH’ (SOT23W, fits SC-59A solder-pad layout) 3.00 .118 2.70 .106 0.15 [.006] M C A B 3.04 .120 2.80 .110 A 8º 0º B 3 0.20 .008 0.08 .003 2.10 .083 1.85 .073 Preliminary dimensions, for reference only Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only (reference JEDEC TO-236 AB, except case width and terminal tip-to-tip) Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Hall element (not to scale) A 0.96 .038 0.60 .024 0.25 .010 A NOM 1 2 0.25 .010 3X SEATING PLANE 0.10 [.004] C 3X 0.50 .020 0.30 .012 C SEATING PLANE GAUGE PLANE 1.17 .046 0.75 .030 0.20 [.008] M C A B 0.15 .006 0.00 .000 0.95 .037 1.90 .075 12 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Micropower, Ultrasensitive Hall Effect Switch A3211 and A3212 PACKAGE DESIGNATOR ‘UA’ .164 4.17 .159 4.04 .062 1.57 .058 1.47 C .122 3.10 .117 2.97 B .085 2.16 MAX .031 0.79 REF A .017 0.44 .014 0.35 .640 16.26 .600 15.24 1 2 3 .019 0.48 .014 0.36 .050 1.27 NOM Dimensions in inches Metric dimensions (mm) in brackets, for reference only A Dambar removal protrusion (6X) B Ejector mark on opposite side C Hall element (not to scale) 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. Copyright © 2002, 2006 Allegro MicroSystems, Inc. 13 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com