A1266 ALLEGRO

Document overview

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Technical content

The A1266 integrated circuit is an ultrasensitive Hall-effect switch with 3D omnipolar magnetic actuation. The single silicon chip includes: three Hall plates, multiplexer, small- signal amplifier, chopper stabilization, Schmitt trigger, and NMOS output transistors. The device outputs turn on when a magnetic field of sufficient strength is applied to the sensor in any orientation. Removal of the magnetic field will turn the output off. Two versions of the A1266 offer a choice of output format: separate X, Y , and Z outputs, or a combined X+Y+Z output. The low operating supply voltage, 2.5 to 5.5 V , and unique clocking algorithm assist in reducing the average power consumption, making it ideal for battery operation (e.g., the power consumption is less than 25 μW with a 3.3 V supply). The small geometries of the BiCMOS process allow for ultrasmall packages suitable for even space-constrained applications. In this case, a modified SOT23-W surface-mount package is available in a 3-pin (combined output) or a 5-pin (separate outputs) configuration, magnetically optimized for use in a variety of orientations. The packages are lead (Pb) free and RoHS-compliant, with 100% matte-tin leadframe plating. A1266-DS, Rev. 2

  • True 3D sensing
  • Omnipolar operation with either north or south pole
  • 2.5 to 5.5 V operation
  • Low supply current
  • High sensitivity, BOP typically 25 G
  • Chopper-stabilized offset cancellation □ Superior temperature stability □ Extremely low switchpoint drift □ Insensitive to physical stress
  • Solid-state reliability
  • Choice of output format □ Separate X, Y , and Z outputs □ Combined (X+Y+Z) output
  • Tiny SOT-23 packages Micropower Ultrasensitive 3D Hall-Effect Switch PACKAGES: Functional Block Diagram Not to scale A1266 VDD X Hall YH all Z Hall Hall Amp. Dynamic Of fset Cancellatio n Low-Pass Filter ToAll Subcircuits Sample, Hold & Averaging Demultiplexer Output Logic GND OUTX (OUT) OUTY (n/a) OUTZ (n/a) Note for Pin Designations: Triple-Output (Single Output) Options FEATURES AND BENEFITS DESCRIPTION 5-Pin SOT23-W 3-Pin SOT23-W

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A. Absolute Maximum Ratings Characteristic Symbol Notes Rating Unit Forward Supply Voltage VDD 5.5 V Reverse Supply Voltage VRDD –0.3 V Magnetic Flux Density B Unlimited G Output Off Voltage VOUT 5.5 V Reverse Output Voltage VROUT –0.3 V Continuous Output Current IOUT 3 mA Reverse Output Current IROUT –3 mA Operating Ambient Temperature TA Range E –40 to 85 °C Maximum Junction Temperature TJ(MAX) 165 °C Storage Temperature Tstg –65 to 170 °C Selection Guide Part Number Packing Package Description A1266ELHLT-T 7-in. reel, 3000 pieces per reel 5-pin SOT23-W Three independent outputs of X, Y, and Z A1266ELHLX-T 13-in. reel, 10000 pieces per reel 5-pin SOT23-W Three independent outputs of X, Y, and Z A1266ELHLT-SO3-T 7-in. reel, 3000 pieces per reel 3-pin SOT23-W Single output of OR (X, Y, and Z ) A1266ELHLX-SO3-T 13-in. reel, 10000 pieces per reel 3-pin SOT23-W Single output of OR (X, Y, and Z ) SPECIFICATIONS Terminal List Table Pin Number A1266ELHLT-T and A1266ELHLX-T A1266ELHLT-SO3-T and A1266ELHLX-SO3-T Symbol Description Symbol Description

1 VDD Power Supply VDD Power Supply

2 OUTX Output of X magnetic field direction OUT X+Y+Z output

3 OUTY Output of Y magnetic field direction GND Ground

4 GND Ground – –

5 OUTZ Output of Z magnetic field direction – –

A1266ELHLT-T and A1266ELHLX-T Pin-Outs 1VDD OUT GND A1266ELHLT-SO3-T and A1266ELHLX-SO3-T Pin-Outs Z XY

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Thermal Characteristics The A1266’s power consumption is extremely low. On-chip power dissipation will not be an issue under normal operating conditions. Characteristic Symbol Notes Rating Unit Package Thermal Resistance RθJA Package LH-3, 2-layer PCB with 0.463 in.2 of copper area, each side connected by thermal vias 110 °C/W Package LH-5, 4-layer board based on the JEDEC standard. 124 °C/W 20 40 60 80 100 120 140 160 180 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 4-Lay er PCB, Package LH-5(R θJA = 124ºC/W) Temperature (ºC) Power Dissipation, P (mW D 2-Layer PCB, Package LH-3 θJA = 110ºC/W) Maximum Power Dissipation versus Ambient Temperature

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. ELECTRICAL CHARACTERISTICS: valid over VDD = 2.5 to 5 V and full operating temperature range (unless otherwise specified) Characteristics Symbol Test Conditions Min. Typ.1 Max. Unit Supply Voltage VDD Operating, TJ < 165°C 2.5 3.3 5.5 V Output Leakage Current IOUTOFF B < BRP – – 10 µA Output On Voltage VOUT(SAT) IOUT = 2 mA, B > BOP – 50 500 mV Awake Time tawake – 300 – µs Mode Cycle Period tperiod – 165 – ms Chopping Frequency fC – 800 – kHz Supply Current IDD(EN) Chip Awake (Enabled) – – 3.6 mA IDD(DIS) Chip Asleep (Disabled), VDD = 2.5 V, TA = 25°C – – 15 µA IDD(AVG) VDD = 2.5 V, TA = 25°C – 7.8 21 µA VDD = 5 V, TA = 25°C – 9.5 40 µA MAGNETIC CHARACTERISTICS: valid over VDD = 2.5 to 5 V and full operating temperature range (unless otherwise specified) Characteristics Symbol Test Conditions Min. Typ. Max. Unit2 Operate Point3 BOPS South pole to left, bottom, or branded face side (see Figure 1) – 25 40 G BOPN North pole to left, bottom, or branded face side (see Figure 1) –40 –25 – G Release Point BRPS South pole to left, bottom, or branded face side (see Figure 1) 5 17.5 – G B RPN North pole to left, bottom, or branded face side (see Figure 1) – –17.5 –5 G Hysteresis 3 BHYS BOPS – BRPS, BOPN – BRPN – 7.5 – G N S N S Z N S XY Figure 1: Three Dimensions of Magnet Orientation. Applied field may be either north or south polarity. 1 Typical data are at TA = 25°C and VDD = 3.3 V (unless otherwise noted). 2 1 G (gauss) = 0.1 mT (millitesla)

3 Applicable to all directions (X, Y, and Z)

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. CHARACTERISTIC DATA V (V)DD IDD(A VG) (µA) T (ºC)A -40 -60 -40 -20 0 40 60 80 100 TA (ºC) IDD(A VG) (µA) VDD(V) 2.5 3.3 Average Supply Current vs. Supply Voltage Average Supply Current vs. Ambient Temperature 100 200 250 300 350 450 500 V (V)DD V OUT(SA (mV) T (ºC)A X Output -40 400 150 Y and Z -40 100 200 250 300 350 450 500 V OUT(SA (mV) VDD(V) X Output 400 150 Y and Z -60 -40 -20 0 40 60 80 10020 TA (ºC) 2.5 3.3 2.5 3.3 Average Low Output Voltage vs. Supply Voltage Average Low Output Voltage vs. Ambient Temperature IOUT = 20 mA 100 150 200 250 300 V (V)DD tPERIOD (ms) T (ºC)A -40 -60 -40 -20 0 40 60 80 100 TA (ºC) VDD(V) 2.5 3.3 100 150 200 250 300 tPERIOD (ms) Average Period vs. Supply Voltage Average Period vs. Ambient Temperature

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. -40 -30 -20 -10 V (V)DD B OP (G) 20 -40 -40 T( ºC)A BOPS BOPN VDD(V) BOPS 2.5 3.3 BOPN 2.5 3.3 -60 -40 -20 0 40 60 80 10020 TA (ºC) -40 -30 -20 -10 B OP (G) Average X-Axis Operate Point vs. Supply Voltage Average X-Axis Operate Point vs. Ambient Temperature -40 -30 -20 -10 V (V)DD B OP (G) -40 -40 T (ºC)A BOPS BOPN VDD(V) BOPS 2.5 3.3 BOPN 2.5 3.3 -60 -40 -20 0 40 60 80 10020 TA (ºC) -40 -30 -20 -10 B OP (G) Average Y-Axis Operate Point vs. Supply Voltage Average Y-Axis Operate Point vs. Ambient Temperature -40 -30 -20 -10 V (V)DD B OP (G) -40 -40 T (ºC)A BOPS BOPN VDD(V) BOPS 2.5 3.3 BOPN 2.5 3.3 -60 -40 -20 0 40 60 80 10020 TA (ºC) -40 -30 -20 -10 B OP (G) Average Z-Axis Operate Point vs. Supply Voltage Average Z-Axis Operate Point vs. Ambient Temperature

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. -40 -30 -20 -10 V (V)DD B RP (G) -40 -40 T (ºC)A BRPS BRPN VDD(V) BRPS 2.5 3.3 BRPN 2.5 3.3 -60 -40 -20 0 40 60 80 10020 TA (ºC) -40 -30 -20 -10 B RP (G) Average X-Axis Release Point vs. Supply Voltage Average X-Axis Release Point vs. Ambient Temperature -40 -30 -20 -10 V (V)DD B RP (G) -40 -40 T (ºC)A BRPS BRPN VDD(V) BRPS 2.5 3.3 BRPN 2.5 3.3 -60 -40 -20 0 40 60 80 10020 TA (ºC) -40 -30 -20 -10 B RP (G) Average Y-Axis Release Point vs. Supply Voltage Average Y-Axis Release Point vs. Ambient Temperature -40 -30 -20 -10 V (V)DD B RP (G) -40 -40 T (ºC)A BRPS BRPN VDD(V) BRPS 2.5 3.3 BRPN 2.5 3.3 -60 -40 -20 0 40 60 80 10020 TA (ºC) -40 -30 -20 -10 B RP (G) Average Z-Axis Release Point vs. Supply Voltage Average Z-Axis Release Point vs. Ambient Temperature

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. V (V)DD B HYS (G) -40 -40 T (ºC)A BHYS(S) BHYS(N) VDD(V) BHYS(S) 2.5 3.3 2.5 3.3 -60 -40 -20 0 40 60 80 10020 TA (ºC) B HYS (G) BHYS(N) Average X-Axis Hysteresis vs. Supply Voltage Average X-Axis Hysteresis vs. Ambient Temperature V (V)DD B HYS (G) -40 -40 T (ºC)A BHYS(S) BHYS(N) VDD(V) BHYS(S) 2.5 3.3 2.5 3.3 -60 -40 -20 0 40 60 80 10020 TA (ºC) B HYS (G) BHYS(N) Average Y-Axis Hysteresis vs. Supply Voltage Average Y-Axis Hysteresis vs. Ambient Temperature V (V)DD B HYS (G) -40 -40 T (ºC)A BHYS(S) BHYS(N) VDD(V) BHYS(S) 2.5 3.3 2.5 3.3 -60 -40 -20 0 40 60 80 10020 TA (ºC) B HYS (G) BHYS(N) Average Z-Axis Hysteresis vs. Supply Voltage Average Z-Axis Hysteresis vs. Ambient Temperature

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. FUNCTIONAL DESCRIPTION Low Average Power To keep average power low, internal timing circuitry activates the sensor of each axis for 100 µs (followed by a low power sleep time, t sleep, of 54.9 ms). This awake and sleep cycle occurs three times for each tperiod, such that all three axes are sampled in tperiod. The short “awake” time allows for stabilization prior to the sensor sampling and data latching at the end of each tawake cycle. The outputs during each tsleep cycle are latched in the last sampled state. The supply current is not affected by the output states. Operation For the single output option of the A1266, the output switches low (turns on) when a magnetic field perpendicular to one of the three Hall sensors, either the X, Y , or Z direction, exceeds the operate point, B OPS (or is less than BOPN). The A1266 triple out- put option is configured with three separate outputs (X, Y , or Z), which switch low (turns on) when a magnetic field perpendicular to the corresponding Hall sensor (X, Y , or Z) exceeds the oper- ate point, B OPS (or is less than BOPN). 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, 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. After turn-on, the output voltage is V OUT. Powering-on the device in the hysteresis region, between BOP and BRP, allows an inde- terminate output state. The correct state is attained after the first excursion beyond BOP or BRP. Device Power-On tawake X Axis tawake Z Axis tawake Y AxisSleep Sleep Sleep IDD(EN) IDD(DIS) tperiod t= 300 µs [t (X) + t (Y) + t (Z)]awake awake awake awake t= 165 ms (t + 3 × t)period awake sleep tsleep period awake= (t –t )/3 = 54.9 mstsleep Awake Sleep Sample X Sample Y Sample Z Sample X Latch Output Latch Output Latch Output Latch Output Figure 2: Device Sleep and Awake Mode Cycle

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A.

Applications

It is strongly recommended that an external capacitor is con- nected (in close proximity to the Hall sensor IC) between the supply and ground of the device to reduce both external noise and noise generated by the chopper-stabilization technique. As shown in Figure 4, a 0.1 µF capacitor is typical. Extensive applications information on magnets and Hall-effect sensors is available in:

  • Hall-Effect IC Applications Guide, AN27701,
  • Hall-Effect Devices: Guidelines for Designing Subassemblies Using Hall-Effect Devices AN27703.1
  • Soldering Methods for Allegro’ s Products – SMD and Through-Hole, AN26009 All are provided on the Allegro website: www.allegromicro.com

0 B– 0 B+

VOUT(HIGH) VOUT(SAT) BHYSBHYS V OUT Switch to Low Switch to Low Switch to HighSwitch to High BOPN B RPN B RPS BOPS Figure 3: Switching Behavior of Omnipolar Switches On the horizontal axis, the B+ direction indicates increasing south polarity magnetic field strength, and the B– direction indicates decreasing south polarity field strength (including the case of increasing north polarity)

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Typical Application Circuits A1266ELHLT-SO3-T AND A1266ELHLX-SO3-T For sensors configured with the single output option, one pin reports the output state from any of the three Hall elements. VS CBYP 0.1 µF VDD GND GND RLOAD Sensor Output A1266 OUT VS CBYP 0.1 µF VDD GND GND RLOAD RLOAD RLOAD Sensor Outputs A1266 OUTX OUTY OUTZ A1266ELHLT-T AND A1266ELHLX-T For sensors configured with the triple output option, the three separate open drain outputs report the output state from the cor- responding Hall elements. Figure 4: Typical Application Circuit for the Single Output Selection Figure 5: Typical Application Circuit for the Triple Output Selection

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. A limiting factor for switchpoint accuracy when using Hall-effect technology is the small signal voltage developed across the Hall plate. This voltage is proportionally small relative to the offset that can be produced at the output of the Hall sensor. This makes it difficult to process the signal and maintain an accurate, reliable output over the specified temperature and voltage range. Chopper stabilization is a proven approach used to minimize Hall offset. The Allegro patented technique, dynamic quadrature offset cancellation, removes key sources of the output drift induced by temperature and package stress. This offset reduction technique is based on a signal modulation-demodulation process. Figure 6 illustrates how it is implemented. The undesired offset signal is separated from the magnetically induced signal in the frequency domain through modulation. The subsequent demodulation acts as a modulation process for the offset, causing the magnetically induced signal to recover its orig- inal spectrum at baseband while the DC offset becomes a high- frequency signal. Then, using a low-pass filter, the signal passes while the modulated DC offset is suppressed. Allegro’s innova- tive chopper-stabilization technique uses a high-frequency clock. The high-frequency operation allows a greater sampling rate that produces higher accuracy, reduced jitter, and faster signal processing. Additionally, filtering is more effective and results in a lower noise analog signal at the sensor output. Devices such as the A1266 that use this approach have an extremely stable quies- cent Hall output voltage, are immune to thermal stress, and have precise recoverability after temperature cycling. This technique is made possible through the use of a BiCMOS process, which allows the use of low-offset, low-noise amplifiers in combination with high-density logic and sample-and-hold circuits. Chopper Stabilization Amp. Multiplexer Low-Pass Filter Sample, Hold & Averaging VDD Figure 6: Model of Chopper-Stabilization Circuit (Dynamic Offset Cancellation)

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. PACKAGE OUTLINE DRAWINGS AX B B C C D For Reference Only – Not for Tooling Use (Reference DWG-9069) 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 Active Area Depth, X Axis, 1.49 ±0.2

0.20 MIN

2.40 0.70 0.95 1.00 PCB Reference Layout View Standard Branding Reference View NNN Reference land pattern layout; 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 Hall Elements (E1, E2, and E3), not to scale D D D D D D E3 E2 D D D D D SEATING PLANE GAUGE PLANE 0.55 REF 0.25 BSC 0.95 BSC Branded Face 2.90 0.17 REF 0.11 REF +0.10 –0.20 4° ±4° 8X 12° REF 0.180+0.020 –0.053 0.05+0.10 –0.05

0.25 MIN

1.91+0.19 –0.06 2.98+0.12 –0.08 1.00 ±0.13 0.40 ±0.10 AY Active Area Depth, Y Axis, 1.45 ±0.15 AZ Active Area Depth, Z Axis, 0.28 ±0.04 AX AY AZ Figure 7: Package LH, 5-Pin SOT23-W

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Figure 8: Package LH, 3-Pin SOT23-W B B C C D For Reference Only – Not for Tooling Use (Reference DWG-2840) 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 2.40 0.70 0.95 1.00 PCB Reference Layout View Standard Branding Reference View NNN Reference land pattern layout; 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 Hall Elements (E1, E2, and E3), not to scale D D D D D D D D 0.55 REF 0.95 BSC Branded Face 2.90 0.17 REF 0.11 REF +0.10 –0.20 8X 12° REF 0.05+0.10 –0.05 2.98+0.12 –0.08 1.00 ±0.13 0.40 ±0.10 D D E3D SEATING PLANE GAUGE PLANE

0.25 BSC

4° ±4° 0.180+0.020 –0.053 1.91+0.19 –0.06 AX Active Area Depth, X Axis, 1.49 ±0.2 AY Active Area Depth, Y Axis, 1.45 ±0.15 AZ Active Area Depth, Z Axis, 0.28 ±0.04 AZAX AY

Micropower Ultrasensitive 3D Hall-Effect SwitchA1266 Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. For the latest version of this document, visit our website: www.allegromicro.com

Revision History

Revision Revision Date Description of Revision – March 20, 2015 Initial Release

1 May 5, 2015 Revised IDD(EN) value and Figure 1

2 September 22, 2015

Added 3-pin SOT23-W package option and included explicit Active Area Depth for 3D sensor in both package drawings; revised IDD(AVG) values and Figure 1; revised pin labels in Functional Block Diagram Copyright ©2015, 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.