A4984SLPTR-T Allegro Microsystems Inc, A4984SLPTR-T Datasheet - Page 12

• Manufacturer Part Number: A4984SLPTR-T
• Description: IC STEPPER MOTOR DRIVER 24TSSOP
• Manufacturer: Allegro Microsystems Inc

Specifications of A4984SLPTR-T

• Applications: Stepper Motor Driver
• Number Of Outputs: 1
• Current - Output: ±2A
• Voltage - Load: 8 V ~ 35 V
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -20°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-TSSOP Exposed Pad, 24-eTSSOP, 24-HTSSOP
• Motor Type: Stepper
• No. Of Outputs: 2
• Output Current: 2A
• Output Voltage: 35V
• Supply Voltage Range: 3V To 5.5V
• Driver Case Style: TSSOP
• No. Of Pins: 24
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 620-1377 - Board Eval Motor Control A4984
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 620-1341-2

A4984
Layout. The printed circuit board should use a heavy ground-
plane. For optimum electrical and thermal performance, the
A4984 must be soldered directly onto the board. On the under-
side of the A4984 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.
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 pad and the ground plane
directly under the A4984, 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.
GND
R4
OUT2B
C3
C4
C7
C6
OUT2A OUT1A
GND
ROSC
VDD
U1
C1
VBB
OUT1B
R5
CAPACITANCE
DMOS Microstepping Driver with Translator
BULK
GND
ES package configuration shown
Application Layout
GND
C2
The two input capacitors should be placed in parallel, and as close
to the device supply pins as possible. The ceramic capacitor (C7)
should be closer to the pins than the bulk capacitor (C2). This
is necessary because the ceramic capacitor will be responsible
for delivering the high frequency current components.The sense
resistors, RSx , should have a very low impedance path to ground,
because they must carry a large current while supporting very
accurate voltage measurements by the current sense comparators.
Long ground traces will cause additional voltage drops, adversely
affecting the ability of the comparators to accurately measure the
current in the windings. The SENSEx pins have very short traces
to the RSx resistors and very thick, low impedance traces directly
to the star ground underneath the device. If possible, there should
be no other components on the sense circuits.
OUT2B
And Overcurrent Protection
C4
C3
Thermal Vias
C7
OUT2B
ENABLE
GND
CP1
CP2
VCP
PCB
C6
R4
OUT2A
115 Northeast Cutoff, Box 15036
A4984
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
A4984
ROSC
PAD
OUT1A
R5
OUT1B
STEP
GND
VDD
REF
DIR
Solder
Trace (2 oz.)
V
Signal (1 oz.)
Ground (1 oz.)
Thermal (2 oz.)
DD
OUT1B
C1
V
BB
C2
12