Data Sheet 27622.61G A3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH 2 x 2 mm MLPD Package A3212EELLT-T The A3212 integrated circuit is an ultra-sensitive, pole independent Hall-effect switch with a latched digital output. This sensor is 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. Unlike other Hall-effect switches, either a north or south pole of sufficient strength will turn the output on; in the absence of a magnetic field, the output is off. The polarity independence and minimal power requirement allow these devices to easily replace reed switches for superior reliability and ease of manufacturing, while eliminating the requirement for signal conditioning. 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. Approximate actual size ABSOLUTE MAXIMUM RATINGS 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 optimized solutions for most applications. Miniature low-profile surface-mount package types EH and EL (0.75 and 0.50 mm nominal height) are leadless, LH is a leaded low-profile SMD, and UA is a three-lead SIP for through-hole mounting. Each package is available in a lead (Pb) free version (suffix, –T) with 100% matte tin plated leadframe. EL package for limited release, engineering samples available. Supply Voltage, VDD .............................. 5 V Magnetic Flux Density, B .......... Unlimited Output Off Voltage, VOUT ...................... 5 V FEATURES ■ Micropower Operation Junction Temperature, TJ ................ +170°C ■ Operation with North or South Pole Operating Temperature, TA Range 'E-' .................... -40°C to +85°C Range 'L-' .................. -40°C to +150°C ■ 2.5 V to 3.5 V Battery Operation ■ Chopper Stabilized Superior Temperature Stability Extremely Low Switch-Point Drift Insensitive to Physical Stress ■ ESD Protected to 5 kV ■ Solid-State Reliability ■ Small Size ■ Easily Manufacturable with Magnet Pole Independence Output Current, IOUT ........................... 1 mA Storage Temperature Range, TS .............................. -65°C to +170°C Caution: These CMOS devices have input static protection (Class 3) but are still susceptible to damage if exposed to extremely high static electrical charges. A3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH Product Selection Guide Use complete part numbers when ordering Pb-free Packing* (Units/Pack) – Tape and Reel (3000) A3212EEHLT–T Yes Tape and Reel (3000) A3212EELLT–T Yes Tape and Reel (2000) – Tape and Reel (3000) Yes Tape and Reel (3000) – Bulk Pack (500) Yes Bulk Pack (500) Part Number A3212EEHLT A3212ELHLT A3212ELHLT–T A3212EUA A3212EUA–T A3212LLHLT A3212LLHLT–T A3212LUA A3212LUA–T – Tape and Reel (3000) Yes Tape and Reel (3000) – Bulk Pack (500) Yes Bulk Pack (500) Ambient Temperature TA (°C) Package Leadless Surface Mount –40 to 85 3-Pin Surface Mount SIP-3 Through Hole, Straight Lead 3-Pin Surface Mount –40 to 150 SIP-3 Through Hole, Straight Lead *Contact Allegro for additional packaging and handling options. FUNCTIONAL BLOCK DIAGRAM SUPPLY SWITCH LATCH OUTPUT SAMPLE & HOLD X DYNAMIC OFFSET CANCELLATION TIMING LOGIC GROUND Dwg. FH-020-5 2 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH 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 2 Dwg. PH-016-1 3 OUTPUT 1 GROUND OUTPUT 2 GROUND SUPPLY 1 SUPPLY DD Dwg. PH-016 Pinning is shown viewed from branded side. www.allegromicro.com 3 Copyright © 2002, 2003 Allegro MicroSystems, Inc. A3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH ELECTRICAL CHARACTERISTICS over operating voltage and temperature range (unless otherwise specified). Limits Characteristic Symbol Test Conditions Min. Typ. Max. Units 2.5 2.75 3.5 V Supply Voltage Range VDD Operating1 Output Leakage Current IOFF VOUT = 3.5 V, BRPN < B < BRPS – <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 – % fC – 340 – kHz Duty Cycle Chopping Frequency Supply Current IDD(EN) Chip awake (enabled) – – 2.0 mA IDD(DIS) Chip asleep (disabled) – – 8.0 µA IDD(AVG) VDD = 2.75 V – 5.1 10 µA VDD = 3.5 V – 6.7 10 µA NOTES: 1. Operate and release points will vary with supply voltage. 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. MAGNETIC CHARACTERISTICS over operating voltage and temperature range (unless otherwise specified). Limits Characteristic Symbol Operate Points BOPS Release Points Hysteresis Test Conditions Min. Typ. Max. Units South pole to branded side – 37 55 G BOPN North pole to branded side -55 -40 – G BRPS South pole to branded side 10 31 – G BRPN North pole to branded side – -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). 4 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH 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 www.allegromicro.com 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 5 A3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH 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. PERIOD IDD(EN) "AWAKE" "SLEEP" SAMPLE & OUTPUT LATCHED B IDD(DIS) +V 0 Dwg. WH-017-2 — HALL VOLTAGE + Dwg. AH-011-2 +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 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. 6 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Dwg. EH-012-1 3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH FUNCTIONAL DESCRIPTION (cont'd) As used here, negative flux densities are defined as less than zero (algebraic convention), i.e., -50 G is less than +10 G. 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. OUTPUT OFF 5V MAX B OPS B OPN OUTPUT VOLTAGE Operation. The output of this device 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. BRPS BRPN OUTPUT ON 0 0 -B +B MAGNETIC FLUX Dwg. GH-043-1 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. 2 OUTPUT SUPPLY (3 V BATTERY) 1 V DD 3 50 kΩ 10 pF X 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 0.1 µF Dwg. EH-013-2 www.allegromicro.com www.allegromicro.com 7 A3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH 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 8 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH 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 www.allegromicro.com 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 9 3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH 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 0.55 .022 0.45 .018 0.50 .020 BSC 0.325 .013 REF 1.025 .040 MAX 2 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 0.15 .006 MIN 1 0.40 .016 NOM www.allegromicro.com 0.50 .020 BSC 1.025 .040 0.775 .031 B 1.350 .053 1.100 .043 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 Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only 3 D Typical pad layout; adjust as necessary to meet application process requirements 0.325 .013 REF 10 3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH PACKAGE DESIGNATOR ‘LH’ (SOT23W, fits SC-59A solder-pad layout) Dimensions in Inches (for reference only) Dimensions in Millimeters (controlling dimensions) 3.10 2.90 0.122 0.114 0.50 0.30 0.020 0.012 0.083 0.073 3 1 2 0.118 0.106 2.10 1.85 0.010 BSC 3 1 2 3.00 2.70 SEATING PLANE REF 0° TO 8° 0.037 0.006 0.000 SEATING PLANE 0.55 0.010 REF 0.045 0.032 0° TO 8° 0.95 MIN BSC BSC GAUGE PLANE GAUGE PLANE 0.022 0.25 MIN BSC 0.0079 0.0050 0.15 0.00 0.25 0.20 0.127 1.13 0.87 Dwg. MA-010-3D in Dwg. MA-010-3D mm 0.028 0.70 3 3 1.00 0.039 2.40 0.094 1 1 2 0.037 Dwg. MA-011-3 in 2 0.95 Dwg. MA-011-3 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. 4. Where no tolerance is specified, dimension is nominal. www.allegromicro.com 11 A3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH PACKAGE DESIGNATOR ‘UA’ Dimensions in Millimeters (for reference only) Dimensions in Inches (controlling dimensions) 0.164 0.159 4.17 4.04 0.062 0.058 45° 1.57 1.47 45° 0.122 0.117 3.10 2.97 45° 45° 0.085 1 2 3 0.031 2.16 1 2 3 16.26 15.24 0.0173 0.0138 0.640 0.600 0.0189 0.0142 SEE NOTE BSC 0.44 0.35 0.48 0.36 SEE NOTE 1.27 0.050 Dwg. MH-014E in BSC 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. 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. 12 0.79 MAX MAX 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Dwg. MH-014E mm 3212 MICROPOWER, ULTRA-SENSITIVE HALL-EFFECT SWITCH 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 13