A3425EK-T Allegro Microsystems Inc, A3425EK-T Datasheet - Page 11

• Manufacturer Part Number: A3425EK-T
• Description: IC SWITCH BIPO DUAL OUT 4-SIP
• Manufacturer: Allegro Microsystems Inc
• Type: Bipolar Latchr

Specifications of A3425EK-T

• Sensing Range: 35G Trip, -35G Release
• Voltage - Supply: 3.3 V ~ 18 V
• Current - Supply: 6mA
• Current - Output (max): 20mA
• Output Type: Digital, Open Drain
• Features: Ultra Sensitive
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 4-SIP
• Hall Effect Type: Bipolar
• Output Current: 70mA
• Sensor Case Style: SIP
• No. Of Pins: 4
• Supply Voltage Range: 3.3V To 18V
• Operating Temperature Range: -40°C To +85°C
• Operating Temperature Max: 85°C
• Svhc: No SVHC (15-Dec-2010)
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

A3425
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
T
P
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
, represents the maximum allow-
R
×
JA
4 mA = 48 mW
J
I
JA
JA
, at P
IN
. Under certain combinations of
140 °C/W = 7°C
. Ambient air temperature,
= 140 °C/W, then:
), without exceeding T
(2)
JA
D
.
, is a fi gure of merit sum-
Typical Thermal Performance
(1)
(3)
Ultra-Sensitive Dual-Channel Quadrature
A
= 25°C,
JC
D
), can
J(max)
, is
,
Example: Reliability for V
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
CC(max)
JA
JA
CC(max)
V
T
D(max)
CC(est)
. If V
= 140 °C/W, T
max
= 6 mA.
is reliable under these conditions.
= T
= T
= P
CC(est)
Hall-Effect Bipolar Switch
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
= 15°C ÷ 140 °C/W = 107 mW
CC(est)
115 Northeast Cutoff, Box 15036
CC
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
, then operation between V
A
. If V
at T
= 107 mW ÷ 6 mA = 18 V
, the application and device can
and V
A
CC(est)
= 150°C, package L, using
CC(max)
CC(max)
≤ V
J
resulting from internal
= 18 V, and
CC(max)
requires enhanced
D(max)
CC(est)
, then reli-
CC(est)
. First,
.
and
10