A4970SLBTR-T Allegro Microsystems Inc, A4970SLBTR-T Datasheet - Page 6

• Manufacturer Part Number: A4970SLBTR-T
• Description: IC PWM MOTOR DVR FULL 24-SOICW
• Manufacturer: Allegro Microsystems Inc

Specifications of A4970SLBTR-T

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

LOGIC CONTROL OF OUTPUT CURRENT
winding current at 100%, 67%, 33%, 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 microprocessor
controlled drive formats.
control the motor at a constant torque between all positions in an eight-step se-
A4970
Subject to Change Without Notice
Preliminary Data Sheet
56 k
R
Two logic level inputs (I
During half-step operations, the I
T
l
H
H
L
L
0
FROM
FROM
56 k
R
March 9, 2011
T
μP
μP
C
820 pF
T
V
REF
CURRENT-CONTROL TRUTH TABLE
+5 V
V
820 pF
C
REF
T
10
11
12
TYPICAL APPLICATION
8
9
1
2
3
4
5
6
7
9
θ
V
θ
2
CC
1
0
I
H
H
L
L
1
and I
1
) allow digital selection of the motor
0
and I
1
allow the microprocessor to
19
24
23
22
21
20
18
17
16
13
15
14
V
V
REF
REF
V
REF
R
R
Output Current
C
C
/30 R
/15 R
/10 R
R
R
C
C
S
S
C
S
C
S
0
= 2/3 I
= 1/3 I
S
= I
TRIP
TRIP
TRIP
STEPPER
MOTOR
V
+
BB
Dual Full-Bridge Motor Driver
quence. 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 I
rapid current decay when switching phases. This
helps to ensure proper motor operation at high step
rates.
select a reduced current level (and reduced power
dissipation) for "hold" conditions and/or increased
current (and available torque) for start-up condi-
tions.
GENERAL
the direction motor winding current fl ows. An in-
ternally generated dead time (approximately 2 μs)
prevents crossover currents that can occur when
switching the PHASE input.
turned-off between steps (I
ing in a fast current decay through the internal
output clamp and fl yback diodes. The fast current
decay is desirable in half-step and high-speed ap-
plications. The PHASE, I
vides continuous control of the peak load current
for micro-stepping applications.
drivers when the junction temperature reaches
+170°C. It is only intended to protect the device
from failures due to excessive junction tempera-
ture and should not imply that output short circuits
are permitted. The output drivers are re-enabled
when the junction temperature cools to +145°C.
500 mA operating current. Under normal operat-
ing conditions, when combined with the excellent
thermal properties of the package designs, this
allows continuous operation of both bridges simul-
taneously at 500 mA.
PHASE
The logic control inputs can also be used to
The PHASE input to each bridge determines
All four drivers in the bridge output can be
Varying the reference voltage, V
Thermal protection circuitry turns-off all
The A4970 output drivers are optimized for
H
L
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
TRUTH TABLE
0
and I
OUT
1
H
L
turn-off all drivers to allow
A
0
,and I
0
= I
1
1
≥ 2.4 V), result-
inputs fl oat high.
OUT
REF
H
L
B
, pro-
6