A1448 ALLEGRO [Allegro MicroSystems], A1448 Datasheet - Page 6

• Manufacturer Part Number: A1448
• Description: Low-Voltage, Full-Bridge Brushless DC Motor Driver with Integrated Hall Sensor IC, PWM Speed Control, Soft-Switching
• Manufacturer: ALLEGRO [Allegro MicroSystems]

A1448
The device must be operated below the maximum junction tem-
perature of the device, T
peak conditions, reliable operation may require derating supplied
power or improving the heat dissipation properties of the appli-
cation. This section presents a procedure for correlating factors
affecting operating T
Allegro MicroSystems website.)
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
small component of R
motion are significant external factors, damped by overmolding.
The effect of varying power levels (Power Dissipation, P
be estimated. The following formulas represent the fundamental
relationships used to estimate T
J
. (Thermal data is also available on the
θJA
ΔT = P
P
T
J
D
. Ambient air temperature, T
J
(max). Under certain combinations of
= V
= T
D
A
IN
Figure 5. A1448 typical application
J
× R
+ ΔT
, at various P
× I
θJA
θJA
IN
, is a figure of merit sum-
Integrated Hall Sensor IC, PWM Speed Control, Soft-Switching,
V
D
BATT
levels.
θJC
C
Low-Voltage, Full-Bridge Brushless DC Motor Driver with
BYP
, is relatively
A
, and air
Power Derating
D
), can
(1)
(2)
(3)
VDD
CONTROL
NC
and Reverse Battery and Short Circuit Protection
A1448
For a load of 30 Ω, and given common conditions such as:
T
I
then:
A worst-case estimate, P
able power level, without exceeding T
and T
LOAD
A
= 25°C, V
P
ΔT = P
T
VOUT2
VOUT1
A
D
J
= 81 mA, and R
GND
.
= 3 V × 83 mA – 2.43 V × 81 mA
= 52.17 mW
= V
= T
= 52.17 mW × 125 °C/W
= 7°C
= 25°C + 7°C
= 32°C
A
DD
D
DD
+ ΔT
× R
× I
= 3 V, I
θJA
DD
M
– V
θJA
DD
D
LOAD
(max), represents the maximum allow-
= 125 °C/W, (see figure 5)
= 83 mA, V
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
× I
LOAD
J
LOAD
(max), at a selected R
= 2.43 V,
θJA
6