HAL710_1 Datasheet, PDF (18/19 Pages) Micronas – Hall-Effect Sensors with Direction Detection

HAL 710, HAL 730
5.5. EMC and ESD
For applications that cause disturbances on the supply
line or radiated disturbances, a series resistor and a
capacitor are recommended (see Fig. 5–1). The series
resistor and the capacitor should be placed as closely
as possible to the Hall sensor.
Please contact Micronas for detailed investigation
reports with EMC and ESD results.
R_V
220 Ω
V_EMC
V_P
1 V_DD
4.7 nF
3 S1-Output
2 S2-Output
R_L 2.4 kΩ R_L 2.4 kΩ
20 pF
20 pF
4 GND
Fig. 5–1: Test circuit for EMC investigations
5.6. Start-up Behavior
Due to the active offset compensation, the sensors
have an initialization time (enable time t_en(O)) after
applying the supply voltage. The parameter t_en(O) is
specified in the “Characteristics” (see Section 3.6. on
page 11).
During the initialization time, the output states are not
defined and the outputs can toggle. After t_en(O), both
outputs will be either high or low for a stable magnetic
field (no toggling) and the Count Output will be low if
the applied magnetic field B exceeds B_ON. The Count
Output will be high if B drops below B_OFF. The Direc-
tion Output will have the correct state after the second
edge (rising or falling) in the same direction.
The device contains a Power-On Reset circuit (POR)
generating a reset when V_DD rises. This signal is used
to disable Test Mode. The generation of this reset sig-
nal is guaranteed when V_DD at the chip rises to a mini-
mum 3.8 V in less than 4 µs monotonically. If this con-
dition is violated, the internal reset signal might be
missing. Under these circumstances, the chip will still
operate according to the specification, but the risk of
toggling outputs during t_en(O) increases; and for mag-
netic fields between B_OFF and B_ON, the output states
of the Hall sensor after applying V_DD will be either low
or high. In order to achieve a well-defined output state,
the applied magnetic field then must exceed B_ONmax,
respectively, drop below B_OFFmin.
18
Oct. 13, 2009; DSH000031_002EN
DATA SHEET
Micronas