HAL710_1 Datasheet, PDF (17/19 Pages) Micronas – Hall-Effect Sensors with Direction Detection

DATA SHEET
HAL 710, HAL 730
5. Application Notes
5.1. Ambient Temperature
Due to the internal power dissipation, the temperature
on the silicon chip (junction temperature T_J) is higher
than the temperature outside the package (ambient
temperature T_A).
T_J = T_A + ΔT
At static conditions and continuous operation, the fol-
lowing equation applies:
ΔT = I_DD × V_DD × R_th
For typical values, use the typical parameters. For
worst case calculation, use the max. parameters for
I_DD and R_th, and the max. value for V_DD from the appli-
cation.
For all sensors, the junction temperature range T_J is
specified. The maximum ambient temperature T_Amax
can be calculated as:
T_Amax = T_Jmax – ΔT
5.3. Signal Delay
The extra circuitry required for the direction detection
increases the latency of the Count and Direction Sig-
nal compared to a simple switch (e.g., HAL 525). This
extra delay corresponds to 0.5 and 1 clock period for
the Direction Signal and Count Signal respectively.
5.4. Test Mode Activation
In order to obtain the normal operation as described
above, two external pull-up resistors with appropriate
values are required to connect each output to an exter-
nal supply, such that the potential at the open-drain
output rises to at least 3 V in less than 10 µs after hav-
ing turned off the corresponding pull-down transistor or
after having applied V_DD.
If the Direction Output is pulled low externally (the
potential does not rise after the internal pull-down tran-
sistor has been turned off), the device enters Manufac-
turer Test Mode.
Direction detection is not functional in Manufacturer
Test Mode. The device returns to normal operation as
soon as the Count Output goes high.
Note: The presence of a Manufacturer Test Mode
requires appropriate measures to prevent acci-
dental activation (e.g., in response to EMC
events).
5.2. Extended Operating Conditions
All sensors fulfill the electrical and magnetic character-
istics when operated within the Recommended Oper-
ating Conditions (see Section 3.5. on page 10).
Supply Voltage Below 3.8 V
Typically, the sensors operate with supply voltages
above 3 V, however, below 3.8 V some characteristics
may be outside the specification.
Note: The functionality of the sensor below 3.8 V is
not tested. For special test conditions, please
contact Micronas.
Micronas
Oct. 13, 2009; DSH000031_002EN
17