A2919SLB Allegro Microsystems Inc, A2919SLB Datasheet - Page 6

• Manufacturer Part Number: A2919SLB
• Description: IC MOTOR DRIVER PWM DUAL 24-SOIC
• Manufacturer: Allegro Microsystems Inc

Specifications of A2919SLB

• Applications: DC Motor Driver, Stepper Motor Driver
• Number Of Outputs: 2/1
• Current - Output: ±750mA
• Voltage - Load: 10 V ~ 45 V
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -20°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

A2919
LOGIC CONTROL OF OUTPUT CURRENT
Two logic level inputs (l
the motor winding current at 100%, 67%, 41%, or 0% of the
maximum level per the table. The 0% output current condition
turns off all drivers in the bridge and can be used as an output
enable function.
These logic level inputs greatly enhance the implementation of
μP-controlled drive formats.
During half-step operations, l
motor at a constant torque between all positions in an eight-step
sequence. This is accomplished by digitally selecting 100%
drive current when only one phase is on and 67% drive current
when two phases are on. Logic highs on both l
drivers to allow rapid current decay.
During quarter-step operation, I
control the motor position in a sixteen-step sequence. This is
accomplished by digitally selecting drive current as shown in the
table (for one quadrant of operation). Logic highs on both I
I
The logic control inputs can also be used to select a reduced
current level (and reduced power dissipation) for ‘hold’
conditions and/or increased current (and available torque) for
start-up conditions.
1
turn off all drivers to allow rapid current decay.
QUARTER-STEPPING CURRENT CONTROL
H
H
l
L
L
CURRENT-CONTROL TRUTH TABLE
0
Current Level
Phase 1
100%
100%
67%
41%
0%
H
H
I
L
L
1
0
and I
0
1
and l
) allow digital selection of
0
and I
V
V
1
V
REF
allow the μP to control the
REF
REF
1
Output Current
Current Level
/24.4 R
allow the μP to
/10 R
/15 R
Phase 2
100%
100%
41%
67%
0%
S
S
0
S
0
= 100% I
and l
= 67% I
= 41% I
1
turn off all
TRIP
TRIP
TRIP
Dual Full-Bridge PWM Motor Driver
0
and
GENERAL
The PHASE input to each bridge determines the direction
motor winding current fl ows. An internally generated deadtime
(approximately 2 μs) prevents crossover currents that can occur
when switching the PHASE input.
All four drivers in the bridge output can be turned off between
steps (l
the internal output clamp and fl yback diodes. The fast current
decay is desirable in half-step and high-speed applications. The
PHASE, l
Varying the reference voltage (V
of the peak load current for micro-stepping applications.
Thermal protection circuitry turns off all drivers when the
junction temperature reaches +170°C. It is only intended
to protect the device from failures due to excessive junction
temperature and should not imply that output short circuits are
permitted. The output drivers are re-enabled when the junction
temperature cools to +145°C.
The A2919 output drivers are optimized for low output
saturation voltages—less than 1.8 V total (source plus sink) at
500 mA. Under normal operating conditions, when combined
with the excellent thermal properties of the batwing package
design, this allows continuous operation of both bridges
simultaneously at 500 mA.
0
= l
0
, and I
1
ž 2.4 V) resulting in a fast current decay through
PHASE
H
L
1
inputs fl oat high.
TRUTH TABLE
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
OUT
REF
H
L
) provides continuous control
A
OUT
H
L
B
5