Hall IC Series Bipolar Latch Hall IC BU52040HFV No.10045EBT05 ●Description BU52040 Hall Effect IC for wheel keys / trackballs is designed to detect a switch in magnetic field from N to S (or vice versa) and maintain its detection result on the output until the next switch. Output is pulled low for S-pole fields and high for N-pole fields. This IC is ideal for detecting the number of shaft rotations inside of a wheel key, trackball, or other similar applications. Using two ICs can also enable detection of rotation direction. ●Features 1) Ideally suited for wheel keys or trackballs 2) Micropower operation (small current consumption via intermittent operation method) 3) Ultra-small outline package 4) Supports 1.8 V supply voltage 5) High ESD resistance: 8kV (HBM) ●Applications Wheel keys (zero-contact selection dials), trackballs, and other interface applications. ●Product Lineup Product name Supply voltage (V) BU52040HFV 1.65～3.30 Operation point Hysteresis (mT) (mT) +/-3.0※ Period (µs) Supply current (AVG) (µA) Output type Package 500 200 CMOS HVSOF5 6.0 ※Plus is expressed on the S-pole; minus on the N-pole ●Absolute Maximum Ratings BU52040HFV (Ta = 25°C) Parameters Power Supply Voltage Output Current Power dissipation Operating Temperature Range Storage Temperature Range Symbol VDD IOUT Pd Topr Tstg Limit Unit ※1 -0.1～4.5 ± 0.5 536※2 -40～+85 -40～+125 V mA mW °C °C ※1. Not to exceed Pd ※2. Reduced by 5.36mW for each increase in Ta of 1℃ over 25℃(mounted on 70mm×70 mm×1.6mm Glass-epoxy PCB) www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 1/12 2010.01 - Rev.B Technical Note BU52040HFV ●Magnetic, Electrical Characteristics BU52040HFV (Unless otherwise specified, VDD=1.80V, Ta=25°C) Limit Parameters Symbol Min Typ Max Unit Conditions Power Supply Voltage VDD 1.65 1.80 3.30 V Operation point Bop 1.0 3.0 5.0 mT Release Point Brp -5.0 -3.0 -1.0 mT Hysteresis Bhys - 6.0 - mT Tp - 500 1200 µs Output High Volｔage VOH VDD - 0.2 - - V B < Brp※3 IOUT =-0.5mA Output Low Voltage VOL - - 0.2 V Bop < B※ IOUT =+0.5mA Supply Current 1 IDD1(AVG) - 200 300 µA VDD =1.8V, Average Supply Current During Startup Time 1 IDD1(EN) - 3.0 - mA VDD =1.8V, During Startup Time Value Supply Current During Standby Time 1 IDD1(DIS) - 2.0 - µA VDD =1.8V, During Standby Time Value Supply Current 2 IDD2(AVG) - 300 450 µA VDD=2.7V, Average Supply Current During Startup Time 2 IDD2(EN) - 4.5 - mA VDD=2.7V, During Startup Time Value Supply Current During Standby Time 2 IDD2(DIS) - 3.5 - µA VDD=2.7V, During Standby Time Value Period 3 ※3. B = Magnetic flux density 1mT=10Gauss Positive (“+”) polarity flux is defined as the magnetic flux from south pole which is direct toward to the branded face of the sensor. After applying power supply, it takes one cycle of period (TP) to become definite output. Radiation hardiness is not designed. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 2/12 2010.01 - Rev.B Technical Note BU52040HFV ●Figure of measurement circuit Bop/Brp Tp VDD VDD VDD 200Ω VDD OUT 100μF GND Oscilloscope OUT GND V The period is monitored by Oscilloscope. Bop and Brp are measured with applying the magnetic field from the outside. Fig.1 Fig.2 Bop,Brp measurement circuit Tp measurement circuit VOH VDD OUT 100μF VDD GND Fig.3 V IOUT＝0.5mA V IOUT＝0.5mA VOH measurement circuit VOL VDD VDD OUT 100μF GND Fig.4 VOL measurement circuit IDD A 2200μF VDD VDD OUT GND Fig.5 IDD measurement circuit www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 3/12 2010.01 - Rev.B Technical Note BU52040HFV ●Reference Data Bop 4.0 2.0 0.0 Brp -2.0 -4.0 -6.0 -8.0 6.0 Ta = 25°C 700 Bop 4.0 PERIOD [ μs] VDD=1.8V MAGNETIC FLUX DENSITY [mT] 2.0 0.0 Brp -2.0 1.8 2.2 2.6 3.0 3.4 SUPPLY VOLTAGE ［V］ Fig.6 Bop,Brp– Ambient temperature Fig.7 Bop,Brp– Supply voltage AVERAGE SUPPLY CURRENT [µA] Ta = 25°C 600 500 400 300 200 1.4 1.8 2.2 2.6 3.0 3.4 3.8 350 Fig.8 TP– Ambient temperature VDD=1.8V 300 250 200 150 100 400 350 Ta = 25°C 300 250 200 150 100 1.4 20 40 60 80 100 1.8 2.2 2.6 3.0 3.4 3.8 SUPPLY VOLTAGE [V] AMBIENT TEMPERATURE [℃] Fig.9 TP– Supply voltage 20 40 60 80 100 AMBIENT TEMPERATURE [℃] 400 -60 -40 -20 0 SUPPLY VOLT AGE [V] -60 -40 -20 0 3.8 AMBIENT TEMPERATURE [℃] 700 400 200 1.4 800 500 300 -6.0 -8.0 20 40 60 80 100 VDD=1.8V 600 -4.0 AVERAGE SUPPLY CURRENT [µA] MAGNETIC FLUX DENSITY [mT] 6.0 -60 -40 -20 0 PERIOD [μs] 800 8.0 8.0 Fig.11 IDD – Supply voltage Fig.10 IDD– Ambient temperature ●Block Diagram BU52040HFV 0.1 µF ＶDD 4 Adjust the bypass capacitor value as necessary, according to voltage noise conditions, etc. LATCH SAMPLE & HOLD × DYNAMIC OFFSET CANCELLATION TIMING LOGIC HALL ELEMENT 5 The CMOS output terminals enable direct connection to the PC, with no external pull-up resistor required. OUT 2 GND Fig.12 PIN No. PIN NAME 1 N.C. 2 GND FUNCTION 5 4 4 5 3 3 2 1 Reverse COMMENT OPEN or Short to GND. GROUND 3 N.C. 4 VDD POWER SUPPLY OPEN or Short to GND. 5 OUT OUTPUT www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 1 2 Surface 4/12 2010.01 - Rev.B Technical Note BU52040HFV ●Description of Operations (Micro-power Operation) The Hall Effect IC for wheel keys / trackballs adopts an intermittent operation method to save energy. At startup, the Hall elements, amp, comparator and other detection circuits power ON and magnetic detection begins. During standby, the detection circuits power OFF, thereby reducing current consumption. The detection results are held while standby is active, and then output. Reference period: 500 µs (MAX. 1200 µs) Reference startup time: 24 µs IDD Period Startup time Standby t Fig.13 (Offset Cancellation) The Hall elements form an equivalent Wheatstone (resistor) bridge circuit. Offset voltage may be generated by a differential in this bridge resistance, or can arise from changes in resistance due to package or bonding stress. A dynamic offset cancellation circuit is employed to cancel this offset voltage. When Hall elements are connected as shown in Fig. 14 and a magnetic field is applied perpendicularly to the Hall elements, voltage is generated at the mid-point terminal of the bridge. This is known as the Hall voltage. Dynamic cancellation switches the wiring (shown in the figure) to redirect the current flow to a 90˚ angle from its original path, and thereby cancels the Hall voltage. The magnetic signal (only) is maintained in the sample/hold circuit during the offset cancellation process and then released. VDD I B× ＋ Hall Voltage － GND Fig.14 www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 5/12 2010.01 - Rev.B Technical Note BU52040HFV (Magnetic Field Detection Mechanism) OUT [V] High Low 0 Brp N-pole B Bop S-pole Magnetic flux density [mT] Fig.15 The IC detects magnetic fields that running horizontal to the top layer of the package. When the magnetic pole switches from N to S, the output changes from high to low; likewise, when the magnetic pole switches from S to N, the output changes from low to high. The output condition is held unit the next switch in magnetic polarity is detected. [Operation in Continuously Changing Magnetic Fields] Direction of magnet movement S Magnet S N N S S N N S S N N Hall IC S Bop N Brp Magnetic field High Hall IC output Low Fig.16 The IC can detect a continuous switch in magnetic field (from N to S and S to N) as depicted above. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 6/12 2010.01 - Rev.B Technical Note BU52040HFV ●Intermittent Operation at Power ON VDD Startup time Standby time Standby time Startup time Supply current (Intermittent operation) Indefinite OUT High (N magnetic field present) (B<Brp) Indefinite interval OUT (S magnetic field present) Low (Bop<B) Indefinite interval OUT (No magnetic field present) (Brp<B< Bop) Fig.17 The Hall Effect IC for wheel keys / trackballs adopts an intermittent operation method in detecting the magnetic field during startup, as shown in Fig. 17. It outputs to the appropriate terminal based on the detection result and maintains the output condition during the standby period. The time from power ON until the end of the initial startup period is an indefinite interval, but it cannot exceed the maximum period, 1200μs. To accommodate the system design, the Hall IC output read should be programmed within 1200μs of power ON, but after the time allowed for the period ambient temperature and supply voltage. Additionally, if a magnetic flux density (B) of magnitude greater than Brp but less than Bop is applied at power ON, the output from the IC remains undefined and will be either high or low until a flux density exceeding the Bop or Brp threshold is applied. ●Application Example Wheel Key Two Hall ICs can enable detection of rotation direction of a magnetic zero-contact wheel key. Circular magnet N N S S N S N S BU52040HFV: 2pcs Mounting Position of Hall IC Inside Wheel Key The angular separation of the two Hall ICs within the footprint of the wheel key depends on N/S division angle of the internal magnet (Φ), and can be set to either Φ/4 or ¾Φ. Mounting the two ICs in this position causes the magnetic phase difference between the ICs to equal ±1/4, and the direction of rotation can be detected by measuring the change in this difference. An example of the magnetic field characteristics for this application is shown in the figure below. 1) Mounting angle of Hall IC = Φ/4 2) Mounting angle of Hall IC = ¾Φ Φ/4 3/4 Φ Hall IC B Hall IC A Hall IC A θ Center of magnet θ Hall IC B www.rohm.com Counterclockwise rotation Center of magnet Mounting Angle of Hall IC © 2010 ROHM Co., Ltd. All rights reserved. N/S division angle of circular magnet = Φ Φ N S N S S N S N Clockwise rotation S N S N S N S N Circular Magnet 7/12 2010.01 - Rev.B Technical Note BU52040HFV Detection of Rotation Direction 1) Mounting angle = Φ/4 Counterclockwise Rotation Clockwise Rotation Magnetic field applied to IC A Magnetic field applied to IC A Magnetic field applied to IC B Magnetic field applied to IC B Bop S Bop S rotation angle rotation angle N N Brp Hall IC A Brp Hall IC A output output High High Low Low Hall IC B Hall IC B output output High High Low Low Clockwise turn: Output of IC B is low when output of IC A becomes high Counterclockwise turn: Output of IC B is high when output of IC A becomes high 2) Mounting angle = ¾Φ Clockwise Rotation Counterclockwise Rotation Magnetic field applied to IC A Magnetic field applied to IC B Magnetic field applied to IC A Magnetic field applied to IC B Bop S Bop S rotation angle N Brp Hall IC A output rotation angle N Brp Hall IC A output High High Low Low Hall IC B Hall IC B output output High High Low Low Clockwise turn: Output of IC B is high when Counterclockwise turn: Output of IC B is a low output of IC A becomes high. when output of IC A becomes high. Because the IC measures changes in magnetic field every 1200 µS, the IC cannot detect changes in rotation at speeds exceeding this period. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 8/12 2010.01 - Rev.B Technical Note BU52040HFV ●Magnet Selection Horizontally Stacked Magnet S S S N N S Vertically Stacked Magnet N N S S N Flux Flux Because the field loop in horizontally stacked magnets extends for a shorter distance than that of vertically stacked magnets, the gap between the magnet and the hall IC must be decreased. Therefore, if horizontally-stacked magnets are used in the application, the thickness of the magnet or the area of each section should be increased to allow for a larger gap between the magnet and IC. Because the IC is unable to detect rotation direction if using magnets that are smaller than the IC’s package size, ensure that the physical size of each N/S division is larger than the IC’s package, and that the ICs are properly mounted with an angular distance of either Φ/4 or ¾Φ from one another (where Φ = N/S division angle of circular magnet). ●IC Reference Position Mounting angle of Hall IC Magnet N/S division angle = Φ Hall IC (x2) Counterclockwise rotation N S N S S N S N Clockwise rotation S N S N SN S N Circular Magnet ●Position of the Hall Effect IC(Reference) HVSOF5 0.6 0.8 0.2 (UNIT：mm) www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 9/12 2010.01 - Rev.B Technical Note BU52040HFV ●Footprint dimensions (Optimize footprint dimensions to the board design and soldering condition) HVSOF5 (UNIT：mm) ●Terminal Equivalent Circuit Diagram Because they are configured for CMOS (inverter) output, the output pins require no external resistance and allow direct connection to the PC. This, in turn, enables reduction of the current that would otherwise flow to the external resistor during magnetic field detection, and supports overall low current (micropower) operation. OUT VDD GND Fig.18 www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 10/12 2010.01 - Rev.B Technical Note BU52040HFV ●Notes for use 1) Absolute maximum ratings Exceeding the absolute maximum ratings for supply voltage, operating conditions, etc. may result in damage to or destruction of the IC. Because the source (short mode or open mode) cannot be identified if the device is damaged in this way, it is important to take physical safety measures such as fusing when implementing any special mode that operates in excess of absolute rating limits. 2) GND voltage Make sure that the GND terminal potential is maintained at the minimum in any operating state, and is always kept lower than the potential of all other pins. 3) Thermal design Use a thermal design that allows for sufficient margin in light of the power dissipation (Pd) in actual operating conditions. 4) Pin shorts and mounting errors Use caution when positioning the IC for mounting on printed circuit boards. Mounting errors, such as improper positioning or orientation, may damage or destroy the device. The IC may also be damaged or destroyed if output pins are shorted together, or if shorts occur between the output pin and supply pin or GND. 5) Positioning components in proximity to the Hall IC and magnet Positioning magnetic components in close proximity to the Hall IC or magnet may alter the magnetic field, and therefore the magnetic detection operation. Thus, placing magnetic components near the Hall IC and magnet should be avoided in the design if possible. However, where there is no alternative to employing such a design, be sure to thoroughly test and evaluate performance with the magnetic component(s) in place to verify normal operation before implementing the design. 6) Operation in strong electromagnetic fields Exercise extreme caution about using the device in the presence of a strong electromagnetic field, as such use may cause the IC to malfunction. 7) Common impedance Make sure that the power supply and GND wiring limits common impedance to the extent possible by, for example, employing short, thick supply and ground lines. Also, take measures to minimize ripple such as using an inductor or capacitor. 8) GND wiring pattern When both a small-signal GND and high-current GND are provided, single-point grounding at the reference point of the set PCB is recommended, in order to separate the small-signal and high-current patterns, and to ensure that voltage changes due to the wiring resistance and high current do not cause any voltage fluctuation in the small-signal GND. In the same way, care must also be taken to avoid wiring pattern fluctuations in the GND wiring pattern of external components. 9) Power source design Since the IC performs intermittent operation, it has peak current when it’s ON. Please taking that into account and under examine adequate evaluations when designing the power source. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 11/12 2010.01 - Rev.B Technical Note BU52040HFV ●Ordering part number B U 5 Part No 2 0 4 0 H Part No 52040 F V Package HFV : HVSOF5 - T R Packaging and forming specification TR: Embossed tape and reel (HVSOF5) HVSOF5 <Tape and Reel information> 4 Tape Embossed carrier tape (0.3) Quantity 3000pcs (0.91) 4 0.2MAX (0.05) 5 (0.8) 5 (0.41) 1.6±0.05 1.0±0.05 Direction of feed TR The direction is the 1pin of product is at the upper right when you hold ( reel on the left hand and you pull out the tape on the right hand ) 3 2 1 1 2 3 1pin 0.13±0.05 S +0.03 0.02 –0.02 0.6MAX 1.2±0.05 (MAX 1.28 include BURR) 1.6±0.05 0.1 S 0.5 0.22±0.05 0.08 Direction of feed M (Unit : mm) www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. Reel 12/12 ∗ Order quantity needs to be multiple of the minimum quantity. 2010.01 - Rev.B Notice Notes No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM Co.,Ltd. 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