MICRONAS 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
May/2007
Available Types and Switching Behavior
Type
Direction Output: Definition of Output State
HAL 710
Output high, when edge of comparator 1 precedes
edge of comparator 2
HAL 730
Output high, when edge of comparator 2 precedes
edge of comparator 1
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.
1
VDD
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.
Reverse
Voltage and
Overvoltage
Protection
Temperature
Dependent
Bias
Hysteresis
Control
Test-Mode
Control
Short Circuit
and
Overvoltage
Protection
Hall Plate 1
Comparator
3
Switch
Output
Count Output
S1
Hall Plate 2
Comparator
Switch
Clock
S2
Direction
Detection
2
Output
Direction Output
4
GND
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: [email protected] ⋅ www.micronas.com