A1145LLHLT Allegro Microsystems Inc, A1145LLHLT Datasheet - Page 9
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A1145LLHLT
Manufacturer Part Number
A1145LLHLT
Description
IC SWITCH HALL EFFECT UNI SOT-23
Manufacturer
Allegro Microsystems Inc
Type
Unipolar Switchr
Specifications of A1145LLHLT
Sensing Range
60G Trip, 10G Release
Voltage - Supply
3.5 V ~ 24 V
Current - Supply
6.9mA
Output Type
Digital, Open Drain
Features
Regulated Voltage
Operating Temperature
-40°C ~ 150°C
Package / Case
SOT-23W
Magnetic Type
Unipolar
Operating Supply Voltage (min)
3.5V
Operating Supply Voltage (typ)
5/9/12/15/18V
Operating Supply Voltage (max)
24V
Mag Sensor Operate Point (g)
60Gs
Mag Sensor Release Point (g)
10Gs
Mag Sensor Hysteresis(g)
15Gs
Package Type
SOT-23W
Pin Count
3
Mounting
Surface Mount
Operating Temp Range
-40C to 150C
Operating Temperature Classification
Automotive
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Current - Output (max)
-
Lead Free Status / RoHS Status
Not Compliant, Contains lead / RoHS non-compliant
A1145
A1146
Power Derating
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
For example, given common conditions such as: T
V
A worst-case estimate, P
able power level (V
at a selected R
A
CC
, and air motion are significant external factors, damped by
ΔT = P
= 12 V, I
T
P
D
J
= T
= V
A
D
CC
+ ΔT = 25°C + 7°C = 32°C
and
×
CC
θJA
×
R
= 4 mA, and R
I
θJA
and T
CC
ΔT = P
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
, represents the maximum allow-
R
×
θJA
4 mA = 48 mW
J
I
θJA
θJA
, at P
IN
. Under certain combinations of
140 °C/W = 7°C
. Ambient air temperature,
= 140 °C/W, then:
), without exceeding T
(2)
θJA
D
.
, is a figure of merit sum-
(1)
(3)
Ultrasensitive Two-Wire Chopper-Stabilized
A
= 25°C,
θJC
D
), can
J(max)
, is
,
Example: Reliability for V
minimum-K PCB.
Observe the worst-case ratings for the device, specifically:
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:
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)
θJA
θJA
CC(max)
P
V
ΔT
D(max)
CC(est)
Unipolar Hall Effect Switches
. If V
= 165°C/W, T
max
= 17 mA.
is reliable under these conditions.
= T
= ΔT
= P
CC(est)
CC(est)
J(max)
D(max)
max
≥ V
to V
J(max)
÷ R
– T
÷ I
CC(max)
θJA
CC(max)
A
CC(max)
= 165°C, V
= 165 °C – 150 °C = 15 °C
= 15°C ÷ 165 °C/W = 91 mW
CC(est)
CC
115 Northeast Cutoff, Box 15036
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
, then operation between V
A
. If V
at T
= 91 mW ÷ 17 mA = 5 V
, the application and device can
and V
A
CC(est)
= 150°C, package UA, using
CC(max)
CC(max)
≤ V
J
= 24 V, and
resulting from internal
CC(max)
requires enhanced
D(max)
CC(est)
, then reli-
CC(est)
. First,
.
and
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