A3908 Allegro MicroSystems, A3908 Datasheet - Page 6

• Manufacturer Part Number: A3908
• Description: Low Voltage DC Motor Driver
• Manufacturer: Allegro MicroSystems

A3908
Layout
The printed circuit board should use a heavy ground-
plane for optimum thermal performance. The A3908
must be soldered directly onto the board. On the
underside of the A3908 package is an exposed pad,
which provides a path for enhanced thermal dissipa-
tion. The thermal pad should be soldered directly to an
exposed surface on the PCB. Thermal vias are used to
transfer heat to other layers of the PCB. Thermal vias
should not have any thermal relief and should be con-
OUTB
OUTA
GND
VDD
CVDD
U1
R2
GND
GND
R1
IN2
IN1
Application Information
A3908 Evaluation Board
nected to internal layers, if available, to maximize the
dissipation area.
Grounding
bounce and offset issues, it is important to have a
low impedance, single-point ground, known as a star
ground, located very close to the device. By making
the connection between the exposed thermal pad and
the groundplane directly under the A3908, that area
becomes an ideal location for a star ground point. A
low impedance ground will prevent ground bounce
Low Voltage DC Motor Driver
CVDD
10 F
In order to minimize the effects of ground
OUTB
GND
VDD
OUTA
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
A3908
PAD
www.DataSheet4U.com
VREF
VSET
IN2
IN1
R2
R1
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