HAL710_2

PRODUCT INFORMATION HAL 710/730 May/2007 HAL® 710/730 Hall-Effect Sensors with Direction Detection The HAL 710/730 Hall switch family is produced in CMOS technology. The sensors include two independent temperature-compensated Hall plates each equipped with active offset compensation and a comparator. The sensors provide two open-drain outputs – one for “count” and one for “direction” detection. The comparator compares the actual magnetic flux through the Hall plates (Hall voltage) with the fixed reference values (switching points). The first comparator directly switches the count output. The phase shift between both comparators determine the state of the direction output. The active offset compensation leads to magnetic parameters which are robust against mechanical stress effects. In addition, the magnetic characteristics are constant over the full supply voltage and temperature range. The sensors are designed for industrial and automotive applications and operate with supply voltages from 3.8 V to 24 V in the ambient temperature range from −40 °C up to 125 °C. The HAL 710/730 family is available in the SMD package SOT-89B-3. Features ◆ Operates from 3.8 V to 24 V supply voltage ◆ Generation of a direction signal ◆ Operates with static magnetic fields and dynamic magnetic fields up to 10 kHz ◆ Overvoltage protection at all pins ◆ Reverse-voltage protection at VDD pin ◆ Magnetic characteristics are robust against mechanical stress effects ◆ Short-circuit protected open-drain outputs by thermal shut down ◆ Constant switching points over a wide supply voltage and temperature range ◆ The decrease of magnetic flux density caused by rising temperature in the sensor system is compensated by a built-in negative temperature coefficient of the magnetic characteristics ◆ High temperature stability for automotive or industrial applications ◆ High ESD rating Major Applications The HAL 710/730 is the optimal system solution for applications, such as: ◆ Endposition detection ◆ RPM measurement of motors in various applications, such as power window ◆ RPM measurements in flow meters ◆ Replacement of micro switches PRODUCT INFORMATION HAL 710/730 Available Types and Switching Behavior Type HAL 710 HAL 730 Direction Output: Definition of Output State Output high, when edge of comparator 1 precedes edge of comparator 2 Output high, when edge of comparator 2 precedes edge of comparator 1 May/2007 System Architecture The Hall-effect sensor is a monolithic integrated circuit that switches in response to magnetic fields. If a magnetic field with flux lines perpendicular to the sensitive area is applied to the sensor, the biased Hall plate forces a Hall voltage proportional to this field. The Hall voltage is compared with the actual threshold level in the comparator. The temperature-dependent bias increases the supply voltage of the Hall plates and adjusts the switching points to the decreasing induction of magnets at higher temperatures. If the magnetic field exceeds the threshold levels, the open-drain output switches to the appropriate state. The builtin hysteresis eliminates oscillation and provides switching behavior of output without bouncing. Magnetic offset caused by mechanical stress is compensated for by using the “switching offset compensation technique”. Therefore, an internal oscillator provides a two phase clock. The Hall voltage is sampled at the end of the first phase. At the end of the second phase, both sampled and actual Hall voltages are averaged and compared with the actual switching point. 4 GND 1 VDD Reverse Voltage and Overvoltage Protection Temperature Dependent Bias Hysteresis Control Test-Mode Control Short Circuit and Overvoltage Protection Hall Plate 1 Comparator 3 Switch S1 Output Count Output Hall Plate 2 Comparator Clock S2 Switch Direction Detection 2 Output Direction Output Fig. 1: Block diagram of the HAL 710/730 All information and data contained in this product information are without any commitment, are not to be considered as an offer for conclusion of a contract, nor shall they be construed as to create any liability. Product or development sample availability and delivery are exclusively subject to our respective order confirmation form. By this publication, Micronas GmbH does not assume responsibility for patent infringements or other rights of third parties which may result from its use. No part of this publication may be reproduced, photocopied, stored on a retrieval system, or transmitted without the express written consent of Micronas GmbH. Edition May 7, 2007; Order No. PI000115-001EN Micronas GmbH ⋅ Hans-Bunte-Strasse 19 ⋅ D-79108 Freiburg (Germany) ⋅ P.O. Box 840 ⋅ D-79008 Freiburg (Germany) Tel. +49-761-517-0 ⋅ Fax +49-761-517-2174 ⋅ E-mail: docservice@micronas.com ⋅ www.micronas.com