ATS674LSETN-LT Allegro Microsystems Inc, ATS674LSETN-LT Datasheet - Page 18

• Manufacturer Part Number: ATS674LSETN-LT
• Description: IC SENSOR GEAR TOOTH 4LEAD
• Manufacturer: Allegro Microsystems Inc
• Type: Special Purposer

Specifications of ATS674LSETN-LT

• Sensing Range: 30% of Air Gap Trip, 40% of Air Gap Release
• Voltage - Supply: 3.3 V ~ 26.5 V
• Current - Supply: 11mA
• Current - Output (max): 20mA
• Output Type: Digital, Open Collector
• Features: Gear Tooth Type
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 4-SIP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

ATS673 and
ATS674
The device must be operated below the maximum junction
temperature of the device, T
peak conditions, reliable operation may require derating sup-
plied power or improving the heat dissipation properties of the
application. This section presents a procedure for correlating
factors affecting operating T
the Allegro MicroSystems Web site.)
The Package Thermal Resistance, R
marizing the ability of the application and the device to dissipate
heat from the junction (die), through all paths to the ambient air.
Its primary component is the Effective Thermal Conductivity,
K, of the printed circuit board, including adjacent devices and
traces. Radiation from the die through the device case, R
relatively small component of R
T
overmolding.
The effect of varying power levels (Power Dissipation, P
be estimated. The following formulas represent the fundamental
relationships used to estimate T

V

A worst-case estimate, P
able power level, without exceeding T
and T
For example, given common conditions such as: T
A
IN
, and air motion are significant external factors, damped by
= 12 V, I
T = P
T = P
T
P
A
D
J
.
= T
= V
A
D
IN
+ T = 25°C + 7°C = 32°C
IN
×
×
= 4 mA, and R
R
I
IN
JA
P
T
= 12 V
D
J
= 48 mW
= T
= V
D(max)
A
D
IN
+ ΔT
×
×
J(max)
J
×
. (Thermal data is also available on
4 mA = 48 mW
, represents the maximum allow-
R
JA
×
J
I
JA
JA
, at P
IN
. Under certain combinations of
140 °C/W = 7°C
= 140 °C/W, then:
Optimized for Automotive Cam Sensing Applications
. Ambient air temperature,
JA
D
J(max)
.
, is a figure of merit sum-
, at a selected R
(3)
(1)
(2)
Self-Calibrating TPOS Gear Tooth Sensor ICs
A
= 25°C,
JC
D
), can
JA
, is
Example: Reliability for V
minimum-K PCB.
Observe the worst-case ratings for the device, specifically:
R
I
the I
table.
Calculate the maximum allowable power level, P
invert equation 3:
This provides the allowable increase to T
power dissipation. Then, invert equation 2:
P
Finally, invert equation 1 with respect to voltage:
The result indicates that, at T
dissipate adequate amounts of heat at voltages ≤V
Compare V
able operation between V
R
V
CC(max)
JA
JA
CC(max)
V
T
D(max)
CC(est)
CC(max)
. If V
= 101 °C/W, T
max
= 11 mA. Note that I
is reliable under these conditions.
= T
= T
= P
CC(est)
CC(est)
at T
J(max)
D(max)
max
A
≥ V
= 25°C given in the Operating Characteristics
to V
÷ R
J(max)
– T
÷ I
CC(max)
JA
CC(max)
A
CC(max)
= 165 °C – 150 °C = 15 °C
= 165°C, V
= 15°C ÷ 101 °C/W = 91 mW
CC(est)
CC
115 Northeast Cutoff, Box 15036
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
, then operation between V
CC(max)
A
. If V
at T
= 91 mW ÷ 11 mA = 8.3 V
, the application and device can
and V
A
CC(est)
= 150°C, package SE, using
CC(max)
at T
CC(max)
A
≤ V
J
= 150°C is lower than
resulting from internal
= 26.5 V, and
CC(max)
requires enhanced
D(max)
CC(est)
, then reli-
CC(est)
. First,
.
and
17