udn3625m Allegro MicroSystems, Inc., udn3625m Datasheet - Page 5

• Manufacturer Part Number: udn3625m
• Description: Powerhall Sensor/drivers For Brushless Dc Motors
• Manufacturer: Allegro MicroSystems, Inc.

dissipation of these devices. Total power dissipated by the device will consist
of power due to the internal regulator, logic and drive circuitry (I
power due to the output drivers (I
circuitry (I
by inserting a Zener diode in the supply line (Z
voltage at the V
minimum operating voltage (6.5 V).
excursions of the outputs. In application, the coupling of the two motor
windings can provide for just such a case. Reducing the coupling between
windings will help, but ground clamp diodes or diodes in series with the
motor windings might be required (D
brushless motors will not require these diodes.
protection. If series diode protection is used with an inductive load (the usual
fan application), a Zener clamp between V
required. The Zener voltage must be greater than the supply voltage but less
than the rated maximum allowable supply voltage.
switched supply line, high-voltage spikes will be generated (especially with
high-current or high-inductance loads) during normal operation, coasting, or
immediately after turn-off. In these situations, a Zener clamp (Z
ground will be required.
default value (I
PWM/I
For example:
I
I
I
CC
O
CL
x V
x V
x V
Some of the power dissipated by the device (I
System requirements usually utilize a diode type of reverse-polarity
With diode reverse-polarity protection, a high-impedance supply, or a
O(SAT)
O
CL
CC
Total package power dissipation = 779.5 mW (max)
ADJ pin.
x duty cycle = 450 mA x 15 V (max) x 1% = 67.5 mW (max)
= 38 mA (max) x 14 V = 532 mW (max)
CL
= 450 mA x 0.4 V (max) = 180 mW (max)
x V
O
CC
MAX) by selection of an external resistor (R
CL
pin under worst-case conditions must be greater than the
x duty cycle).
Care should be taken in evaluating the package power
A note of caution concerns negative (below ground)
BRUSHLESS DC MOTORS
The over-current limit may be reduced from the
SENSOR/DRIVERS FOR
O
x V
C
O(SAT)
or D
S
S
and ground (Z
), and power due to the clamp
in the figure). Most small
A
3625
in the figure). Note that the
CC
x V
P
CC
OWER
B
AND
) can be reduced
in the figure) is
ADJ
B
CC
) from V
) at the
H
3626
x V
ALL
CC
®
),
S
to