A1425LK Allegro Microsystems Inc, A1425LK Datasheet - Page 12

• Manufacturer Part Number: A1425LK
• Description: IC SENSOR HALL EFFECT AC 4-SIP
• Manufacturer: Allegro Microsystems Inc
• Type: Special Purposer

Specifications of A1425LK

• Sensing Range: 11G Trip, -11G Release
• Voltage - Supply: 4 V ~ 26.5 V
• Current - Supply: 7mA
• Current - Output (max): 25mA
• Output Type: Digital, Open Collector
• Features: High Accuracy
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 4-SIP
• Magnetic Type: Monolithic
• Operating Supply Voltage (min): 4V
• Operating Supply Voltage (typ): 5/9/12/15/18/24V
• Operating Supply Voltage (max): 26.5V
• Output Current: 25mA
• Package Type: SIP
• Pin Count: 4
• Mounting: Through Hole
• Operating Temp Range: -40C to 150C
• Operating Temperature Classification: Automotive
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

A1425
Power Derating
The device must be operated below the maximum junction
temperature of the device, T
tions of peak conditions, reliable operation may require derating
supplied 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

For example, given common conditions such as: T
A
CC
, and air motion are signifi cant external factors, damped by
T = P
T = P
= 5.0 V, I
T
P
D
J
= T
= V
A
D
CC
+ T = 25°C + 3.7°C = 28.7°C
×
CC
×
R
= 4.2 mA, and R
I
JA
CC
P
T
D
J
= 5.0 V
= 21.0 mW
= T
= V
A
D
IN
+ ΔT
×
J
J
(max). Under certain combina-
×
. (Thermal data is also available on
×
R
J
I
4.2 mA = 21.0 mW
JA
JA
, at P
IN
×
High Accuracy Analog Speed Sensor IC with Integrated
Filter Capacitor and Dual Zero-Crossing Output Signal
JA
. Ambient air temperature,
177 °C/W = 3.7°C
JA
D
= 177 °C/W, then:
.
, is a fi gure of merit sum-
(1)
(2)
(3)
A
= 25°C,
JC
D
), can
, is
A worst-case estimate, P
able power level (V
T
Example
Reliability for V
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
and V
For example, when a standard diode with a 0.7 V drop is used:
V
CC
J
JA
JA
S
(max), at a selected R
V
(max) = 12 V + 0.7 V = 12.7 V
T
(max) = 7.0 mA.
D
CC(est)
. If V
= 177°C/W, T
(max) = T
CC
max
(max) is reliable under these conditions.
= T
= P
CC(est)
CC(est)
J
D
(max) – T
(max) ÷ I
CC
max
≥ V
to V
J
(max) = 165°C, V
at T
CC
÷ R
CC
(max), I
CC
A
(max), then operation between V
JA
JA
A
CC
D
= 150°C, using minimum-K PCB
(max). If V
CC(est)
(max), represents the maximum allow-
= 165 °C – 150 °C = 15 °C
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
(max) = 84 mW ÷ 7.0 mA = 12 V
= 15°C ÷ 177 °C/W = 84 mW
and T
A
CC
, the application and device can
and V
(max)), without exceeding
A
.
CC(est)
CC
CC
(max) = 26.5 V, and
(max) requires enhanced
J
resulting from internal
≤ V
CC
(max), then reli-
D
CC(est)
(max). First,
.
CC(est)
12