BU52012NVX-TR Datasheet, PDF (12/20 Pages) Rohm – Unipolar Detection Hall ICs

BU52002GUL,BU52003GUL,BU52012NVX,BU52012HFV,BU52013HFV
Technical Note
BU52012HFV, BU52013HFV
VDD
4
HALL
ELEMENT
×
TIMING LOGIC
0.1µF
Adjust the bypass capacitor value as
necessary, according to voltage noise
conditions, etc.
The CMOS output terminals enable direct connection to
the PC, with no external pull-up resistor required.
5 OUT
Fig.38
2
GND
PIN No. PIN NAME
1
N.C.
2
GND
3
N.C.
4
VDD
5
OUT
FUNCTION
GROUND
POWER SUPPLY
OUTPUT
COMMENT
OPEN or Short to GND.
OPEN or Short to GND.
5
4
4
5
123
Surface
321
Reverse
●Description of Operations
(Micropower Operation)
I_DD
Period
Startup time
Standby
Fig.39
(Offset Cancelation)
V_DD
I
B_×
GND
Fig.40
The unipolar detection Hall IC adopts an intermittent operation
method to save energy. At startup, the Hall elements, amp,
comparator and other detection circuit power ON and magnetic
detection begins. During standby, the detection circuits power
OFF, thereby reducing current consumption. The detection results
are held while standby is active, and then output.
Reference period: 50ms (MAX100ms)
Reference startup time: 24µs
t
＋
Hall Voltage
－
The Hall elements form an equivalent Wheatstone (resistor)
bridge circuit. Offset voltage may be generated by a differential in
this bridge resistance, or can arise from changes in resistance
due to package or bonding stress. A dynamic offset cancellation
circuit is employed to cancel this offset voltage.
When Hall elements are connected as shown in Fig. 40 and a
magnetic field is applied perpendicular to the Hall elements,
voltage is generated at the mid-point terminal of the bridge. This
is known as Hall voltage.
Dynamic cancellation switches the wiring (shown in the figure) to
redirect the current flow to a 90˚ angle from its original path, and
thereby cancels the Hall voltage.
The magnetic signal (only) is maintained in the sample/hold
circuit during the offset cancellation process and then released.
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12/19
2010.08 - Rev.C