A4983 View Datasheet(PDF) - Allegro MicroSystems
Part Name
Description
MFG CO.
'A4983' PDF : 16 Pages View PDF
A4983
DMOS Microstepping Driver with Translator
Application Layout
Layout The printed circuit board should use a heavy ground-
plane. For optimum electrical and thermal performance, the
A4983 must be soldered directly onto the board. On the under-
side of the A4983 package is an exposed pad, which provides a
path for enhanced thermal dissipation. 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 connected to
internal layers, if available, to maximize the dissipation area.
Grounding In order to minimize the effects of ground 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 A4983, that area
becomes an ideal location for a star ground point.
A low impedance ground will prevent ground bounce during
high current operation and ensure that the supply voltage remains
stable at the input terminal. The recommended PCB layout shown
in the diagram below, illustrates how to create a star ground
under the device, to serve both as low impedance ground point
and thermal path.
A4983
PCB
Thermal Vias
Solder
Trace (2 oz.)
Signal (1 oz.)
Ground (1 oz.)
Thermal (2 oz.)
RS1
C7
RS2
C9
VBB
C2
1
OUT2B
ENABLE
GND
CP1
C3
CP2
C4
VCP
NC
C6
A4983
PAD
R6
OUT1B
NC
DIR
GND
REF
STEP
VDD
C1
R2
C8
R3
VDD
R1
Allegro MicroSystems, Inc.
10
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
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