Precision Programmable Linear Hall Effect Sensor

www.DataSheet4U.com Precision Programmable* Linear Hall Effect Sensor *Patent Pending MLX90215 Features and Benefits • • • • • • • Programmable Linear Hall IC Quad Switched / Chopper Stabilized Ratiometric Output for A/D Interface Adjustable Quiescent Voltage (VOQ ) Very Low Quiescent Voltage Temperature Drift Adjustable Sensitivity Adjustable Temperature Compensation of Sensitivity Applications • • • Linear Position Sensing Rotary Position Sensing Current Sensing Ordering Information Part No. MLX90215 MLX90215 Temperature Suffix L E Package VA(4 Lead SIP) VA(4 Lead SIP) Temperature Range -40°C to 150°C -40°C to 85°C Functional Diagram VDD OTPROM (ROM) Description 2 The MLX90215 is a Programmable Linear Hall Effect sensor IC fabricated utilizing silicon-CMOS technology. It possesses active error correction circuitry which virtually eliminates the offset errors normally associated with analog Hall Effect devices. All magnetic response functions of the MLX90215 are fully programmable for even greater versatility. The VOQ (VOUT@ B=0), sensitivity, direction of slope and the magnitude of sensitivity drift over temperature, are all programmable. The ratiometric output voltage is proportional to the supply voltage. When using the supply voltage as a reference for an A/D converter, fluctuations of +10% in supply voltage will not affect accuracy. When programmed for a conventional sensitivity (with a positive gain), the voltage at the output will increase as a South magnetic field is applied to the branded face of the MLX90215. Conversely, the voltage output will decrease in the presence of a North magnetic field. The MLX90215 has a sensitivity drift of less than +1% error, and V stability drift of less than +0.4% error, OQ over a broad temperature range. 1 Shift Register (RAM) Program Decoder Hall Plate Chopper DAC DAC DAC 3 4 Pin 1 Pin 2 Pin 3 Pin 4 - VDD (Supply) - Test/Readback Enable - VSS (Ground) - Output Note: Static sensitive device, please observe ESD precautions. MLX90215 Programmable Hall Effect Sensor Rev 4.3 7/6/01 Page 1 Precision Programmable* Linear Hall Effect Sensor *Patent Pending MLX90215 MLX90215 Electrical Specifications Parameter Supply Voltage Supply Current Output Current (1) (2) Symbol Test Conditions VDD IDD IOUT VOQ VOH VOL fSAMP BW BW T RMIN T RMIN ∆VOQ Operating B = 0, VDD = 5V, IOUT = 0 VDD = 5V + 10% 10-Bit Programmable, B = 0 VDD = 5V, IOUT = -2mA VDD = 5V, IOUT = 2mA RoughGain @ Max and Min RoughGain @ Min RoughGain @ Max RoughGain @ Min RoughGain @ Max B = 0, TA = 25oC Min 4.5 2.5 -2 0.5 4.50 Typ 5.0 4.0 4.65 0.35 Max 5.5 6.5 2 4.5 Units V mA mA V V Quiescent Output Voltage Output Voltage (1) Output Voltage (1) Sampling Rate Bandwidth (3) Bandwidth (3) 0.50 40 1.300 V kHz kHz kHz µs µs 4 - 0.130 25 250 -1.5 -20 -40 5 8 - Impulse Response Time (6) Impulse Response Time (6) Offset Voltage Adjustment Resolution Offset Voltage Drift over Temperature Offset Voltage Drift (2) over Temperature Range of Sensitivity (7) Peak to Peak Noise (4) Output Resistance Sensitivity Drift(5) 25 6 1.5 20 40 140 60 mV mV mV mV/mT mV Ω ∆VOQ/∆T B = 0, TA = -40oC to 150oC S < 100mV/mT & VOQ > 0.75V ∆VOQ/∆T B = 0, TA = -40oC to 150oC S > 100mV/mT & VOQ < 0.75V s 13-Bit Programmable ROUT TA = 25 C o -1 - 1 % Notes: (1) If output current and voltage specifications are exceeded, linearity will be degraded. (2) If VOQ is programmed beyond these limits, the temperature compensation may become a problem at high temperatures. It is not recommended to program values of VOQ below 1V or above 4V when sensitivity exceeds 100 mV/mT. Temperature instability can occur on some devices under these conditions. (3) Bandwidth is inversely proportional to ROUGHGAIN. (4) Peak to Peak Noise is a function of ROUGHGAIN setting. See page 5, Peak to Peak Noise versus Sensitivity. (5) Sensitivity drift is independent of other parameters and does not include individual tolerances (∆V OQ or ∆V OQ/∆T). The tolerance for sensitivity is + 1% of its initial value. This does not include tolerance stack-up. (6) If the impulse occurs in the middle of a sample interval, the small signal response delay will double. If a 50% to 100% impulse, slew rate may result in double or triple delay. (7) 1 mT = 10 Gauss Melexis Inc. reserves the right to make changes without further notice to any products herein to improve reliability, function, or design. Melexis does not assume any liability arising from the use of any product or application of any product or circuit described herein. MLX90215 Programmable Hall Effect Sensor Rev 4.3 7/6/01 Page 2 Precision Programmable* Linear Hall Effect Sensor MLX90215 *Patent Pending How does it Work? The MLX90215 programming is done through the output pin, by changing supply voltage levels. Please note that the VDD is raised to approximately 13V and 18V during programming. Any connected components must also tolerate this voltage excursion. When the supply voltage is at 4.5V to 5.5V, the output behaves normally. If the supply voltage is raised to 13V, the output then behaves as an input, or LOAD mode, allowing the 31-bit word to be clocked in. All data is loaded through a single line, with no dedicated clock signal. Clock and data are integrated into one signal which is initiated with the beginning of the L OAD sequence, then clocked with the positive edge of each bit. Variables are changed with the PC software and loaded into the temporary register of the device (RAM) via the timings of the programmer’s microcontroller. Data can be loaded as many times as desired while in LOAD mode. Once a word is loaded, results are checked by observing the output voltage. This can be done with an external Voltmeter attached directly to pin 4 of the device, or with the internal ADC of the programmer. Once the desired program is loaded, the word can be “Zapped” permanently into ROM. This is done when the supply voltage rises above 18V, or ZAP mode, c reating enough current to “Zap” 31 zener diodes which correspond to the temporary register. The ZAP function is a one-time function and cannot be erased. The above description is only for reference. The voltage levels and data transfer rates are completely controlled by the ASIC programmer. For more information on the programmer hardware, contact Melexis and request a datasheet for the SDAP programmer. Programming The Quiescent Offset Voltage (VOQ ) 10 bits, 1024 steps of resolution, are allotted to adjust the Quiescent Offset Voltage (VOQ ). By utilizing the HALFVDD function, the VOQ can be set to one of two ranges. With the HALFVDD function disabled, the VOQ can be programmed within a range of 10% to 90% VDD with about 5mV per step resolution. With the HALFVDD function enabled, the device may be programmed within a 2V to 3V window with less than 1mV per step resolution Programming the Sensitivity (Gain) The sensitivity is programmed with a ROUGHGAIN and a FINEGAIN adjustment. The ROUGHGAIN is adjusted by utilizing three bits, or 8 increments. The FINEGAIN is programmed with 10 bits or 1024 increments. The sensitivity can be programmed within a range of 5mV/mT to 140mV/mT. Another 1 -bit function allows the direction of the sensitivity to be reversed. The INVERTSLOPE function, when activated, will cause the Voltage output of the MLX90215 to decrease in the presence of a South magnetic field, and to increase in the presence of a North magnetic field. Table 2 expresses examples of sensitivity resulting from programming ROUGH GAIN and FINE GAIN codes, with the INVERT SLOPE function turned off. Note: Tables 1 and 2 are examples how various codes affect the Table 2 - Programming Sensitivity RoughGain 0 0 1 1 2 2 3 3 FineGain 0 1023 0 1023 0 1023 0 1023 0 1023 0 1023 0 1023 0 1023 7/6/01 Output 4.1 9.4 6.2 14.6 9.5 22.4 14.2 33.1 21.5 50.4 31.3 72.5 46.2 107 68.9 140 Units mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT mV/mT Table 1 - Programming Offset Voltage (VOQ) HalfVDD 0 0 0 1 1 1 OffsetDAC 0 512 1023 0 512 1023 Output 4.97 2.47 0.03 3.07 2.45 1.83 Units V V V V V V Rev 4.3 4 4 5 5 6 6 7 7 MLX90215 Programmable Hall Effect Sensor Page 3 Precision Programmable* Linear Hall Effect Sensor *Patent Pending MLX90215 Temperature Compensation Temperature compensation (TC) is defined as the change in sensitivity over temperature. Expressed in (Parts Per Million per Degree Celcius) ppm/ o C. TC = Sens T 1 − Sens T 2 1 ppm ∗ ∗ 10 6 o Sens 25 T1− T 2 C SensT1 = Sensitivity measured at Temperature 1 (T1) SensT2 = Sensitivity measured at Temperature 2 (T2) Sens25 = Initial Sensitivity measured at 25o C Table 3 - Temperature Compensation TC Code 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Min -600 -535 -465 -390 -300 -235 -150 -85 125 125 210 285 450 535 600 680 1150 1230 1320 1405 1490 1575 1665 1750 2165 2340 2425 2500 2595 2680 2710 2775 Typical -450 -385 -315 -240 -150 -85 0 65 275 360 435 515 600 685 750 830 1300 1380 1470 1555 1640 1725 1815 1900 2365 2490 2575 2650 2745 2830 2910 2975 Max -300 -235 -165 -90 0 65 150 215 425 510 585 665 750 835 900 980 1450 1530 1620 1705 1790 1875 1965 2950 2565 2640 2725 2800 2895 2980 3110 3175 Units ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC ppm/ oC Programming the Temperature Compensation The MLX90215 has a 5-bit (32 step) programmable adjustment that changes it’s sensitivity drift over a given temperature range. By adjusting the TC code the sensitivity can be programmed to increase as temperature increases to counteract the decrease in magnetic flux most magnets display over temperature. For example a SmCo (Samarium Cobalt) magnet has a temp