ATS645LSH-I1 Allegro Microsystems Inc, ATS645LSH-I1 Datasheet - Page 13

• Manufacturer Part Number: ATS645LSH-I1
• Description: Hall Effect IC
• Manufacturer: Allegro Microsystems Inc

Specifications of ATS645LSH-I1

• Termination Type: Through Hole
• No. Of Pins: 4
• Mounting Type: Through Hole
• Hall Effect Type: Gear Tooth
• Supply Voltage Min: 4V
• Peak Reflow Compatible (260 C): No
• Bandwidth: 40kHz
• Output Type: Digital
• Filter Terminals: Through Hole
• Rohs Compliant: No
• Leaded Process Compatible: No
• Package / Case: 4-SIP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

ATS645LSH
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 (V
at a selected R
For example, given common conditions such as: T
A
CC
, and air motion are signifi cant external factors, damped by
T = P
T = P
= 12 V, I
P
T
D
J
= T
= V
A
D
CC
+ T = 25°C + 7°C = 32°C
×
CC
JA
×
R
= 4 mA, and R
I
JA
and T
CC
P
T
CC(max)
D
J
= 12 V
= 48 mW
= T
= V
A
D(max)
.
A
D
IN
, I
+ ΔT
×
J(max)
J
×
CC(max)
×
. (Thermal data is also available on
R
, represents the maximum allow-
×
4 mA = 48 mW
I
JA
J
JA
JA
, at P
IN
. Under certain combinations of
140 °C/W = 7°C
= 140 °C/W, then:
. Ambient air temperature,
), without exceeding T
(2)
JA
D
.
, is a fi gure of merit sum-
True Zero Speed Miniature Differential Peak-
(1)
(3)
A
= 25°C,
Power Derating
JC
D
), can
J(max)
, is
,
Example: Reliability for V
(I1 trim), using minimum-K PCB
Observe the worst-case ratings for the device, specifi cally:
R
I
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
Detecting Gear Tooth Sensor IC
CC(max)
JA
JA
CC(max)
V
T
D(max)
CC(est)
. If V
= 126°C/W, T
max
= 16 mA.
is reliable under these conditions.
= T
= T
= P
CC(est)
CC(est)
J(max)
D(max)
max
≥ V
to V
J(max)
÷ R
– T
÷ I
CC(max)
JA
CC(max)
A
CC(max)
= 165°C, V
= 165 °C – 150 °C = 15 °C
CC(est)
= 15°C ÷ 126 °C/W = 119 mW
115 Northeast Cutoff
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CC
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
, then operation between V
A
. If V
at T
= 119 mW ÷ 16 mA = 7 V
, the application and device can
and V
A
CC(est)
= 150°C, package SH
CC(max)
CC(max)
J
≤ V
= 24 V, and
resulting from internal
CC(max)
requires enhanced
D(max)
CC(est)
, then reli-
CC(est)
. First,
.
and
12