EC2648 cmos omnipolar tm high sensitivity micropower hall switch page 1 / 5 features and benefits chopper stabilized amplifier stage micropower consumption for battery-powered application omnipolar, output switches with absolute value of north or south pole from magnet high sensitivity for direct reed switch replacement applications applications solid state switch handheld wireless handset awake switch lid close sensor for battery powered devices magnet proximity sensor for reed switch replacement in low duty cycle application description the EC2648 omnipolar tm hall effect sensor ic is fabricated from mixed signal cmos technology. it incorporates advanced chopper-stabilization techniques to provide accurate and stable magnetic switch points. the circuit design provides an internally controlled clocking mechanism to cycle power to the hall element and analog signal processing circuits. this serves to place the high current-consuming portions of the circuit into a ?sleep? mode. periodically the device is ?awakened? by this internal logic and the m agnetic flux from the ha ll element is evaluated against the predefined thresholds. if the flux density is above or below the bop/brp thresholds then the output transistor is driven to change states accordingly. while in the ?sleep? cycle the output transistor is latche d in its previous state. the design has been optimized for service in applications requiring extended operating lifetime in battery powered systems. the output transistor of the EC2648 will be latched on (b op ) in the presence of a sufficiently strong south or north magnetic field the marked side of the package. the output will be latched off (b rp ) in the absence of a magnetic field. the sot-23 device is magnetically inverted from the ua sip device
EC2648 cmos omnipolar tm high sensitivity micropower hall switch page 2 / 5 functional diagram electrical specifications dc operating parameters : t a = 25 , vdd = 3vcc ( unless otherwise specified ) parameter symbol test conditions min typ max units supply voltage v dd operating 2.5 2.75 3.5 v supply current i dd average 10 ua output current i out 1 ma saturation voltage v sat iout = 1ma 0.4 v awake mode time t aw operating 150 us sleep mode time t sl operating 50 70 ms magnetic specifications dc operating parameters : t a = 25 , vdd = 3vcc ( unless otherwise specified ) parameter symbol test conditions min typ max units operating point b op 3.8 6.0 mt release point b rp 0.5 2.1 mt hysteresis b hys 1.7 mt note : 1mt = 10 gauss chopper output gnd vdd sleep awake logic + -- EC2648
EC2648 cmos omnipolar tm high sensitivity micropower hall switch page 3 / 5 absolute maximum ratings supply voltage (operating). v dd ??????????????????. 3v supply current (fault). i dd ???????????.??????. 5ma output voltage, v out ??????????????????. 5v output current (fault) , i out ?????????????????.. 5ma operating temperature range , t a ??????????????? -40 to 85 storage temperature range , t s ??????????????.. -55 to 150 unigue features cmos hall ic technology the chopper stabilized amplifier uses switched capacitor techniques to eliminate the amplifier offset voltage, which, in bipolar devices, is a major source of temperature sensitive drift. cmos makes this advanced technique possible. the cmos chip is also much smaller than a bipolar chip, allowing very sophisticated circuitry to be placed in less space. the small chip size also contributes to lower physical stress and less power consumption. installation comments consider temperature coefficients of hall ic and magnetics, as well as air gap and life time variations, observe temperature limits during wave soldering . typical application package information gnd out vdd 2.5v-3.5v pullup resistor ordering information part no . temperature suffix package temperature range EC2648 e ua -40 to 85 extended EC2648 e sot-23. -40 to 85 extended
EC2648 cmos omnipolar tm high sensitivity micropower hall switch page 4 / 5 performance graphs typical magnetic switchpoints versus vdd 5 4 3 2 1 0 -1 -2 -3 -4 2.2 2.4 2.6 2.8 3 3.2 field strength (mt) bop+ brp+ brp- bop- vdd (v) typical magnetic switchpoints versus temperature field density (mt) 4 3 2 1 0 -1 -2 -3 -4 -40 -20 0 20406080 -40 -20 0 20406080 2 4 6 8 10 12 14 0 typical current consumption versus temperature, vdd=3v current cosumption -80 -60 -40 -20 0 20 40 60 80 0 0.5 1 1.5 2 2.5 3 output switching characteristics output voltage magnetic field (gauss) temperature (c) bop+ brp+ brp- bop- average current (ua) sleep current (ua) awake current (ma)
EC2648 cmos omnipolar tm high sensitivity micropower hall switch page 5 / 5 sot-23 package physical characteristics sot-23 package hall location 0.95 0.80 1.50 1.40 bottom view of sot-23 package 1 2 3 0.56 0.66
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