ATS642LSH Datasheet, PDF (12/16 Pages) Allegro MicroSystems – Two-Wire True Zero Speed Miniature Differential Peak-Detecting Gear Tooth Sensor with Continuous Calibration

ATS642LSH
True Zero Speed Miniature Differential Peak-Detecting Gear Tooth Sensor
Power Supply Protection
The device contains an on-chip regulator and can operate over
a wide V_CC range. For devices that need to operate from an
unregulated power supply, transient protection must be added
externally. For applications using a regulated line, EMI/RFI pro-
tection may still be required. Contact Allegro Microsystems for
information on the circuitry needed for compliance with various
EMC specifications. Refer to figure 7 for an example of a basic
application circuit.
Undervoltage Lockout
When the supply voltage falls below the undervoltage lockout
voltage, V_CC(UV), the device enters Reset, where the output state
returns to the Power-On State (POS) until sufficient V_CC is sup-
plied. I_CC levels may not meet datasheet limits when
V_CC < V_CC(min).
Assembly Description
This sensor is integrally molded into a plastic body that has been
optimized for size, ease of assembly, and manufacturability.
High operating temperature materials are used in all aspects of
construction.
Diagnostics
The regulated current output is configured for two-wire appli-
cations, requiring one less wire for operation than do switches
with the more traditional open-collector output. Additionally,
the system designer inherently gains diagnostics because there is
always output current flowing, which should be in either of two
narrow ranges, shown in figure 8 as I_CC(High) and I_CC(Low). Any
current level not within these ranges indicates a fault condi-
tion. If I_CC > I_CC(High)max, then a short condition exists, and if
I_CC < I_CC(low)min, then an open condition exists. Any value of I_CC
between the allowed ranges for I_CC(High) and I_CC(Low) indicates a
general fault condition.
V+
1
VCC
ATS642
Pins 2 and 3 floating
GND
4
ECU
100 Ω
R_SENSE
C_BYP
0.01 µF
+mA
I_CC(High)max
I_CC(High)min
I_CC(Low)max
I_CC(Low)min
0
Short
Fault
Open
A ^{Range for Valid ICC(HIGH)}
A ^{Range for Valid ICC(LOW)}
Figure 7: Typical Application Circuit
Figure 8: Diagnostic Characteristics of Supply Current Values
ATS642LSH-DS
Allegro MicroSystems, Inc.
12
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com