SLA7060MLF210 ALLEGRO [Allegro MicroSystems], SLA7060MLF210 Datasheet - Page 12

• Manufacturer Part Number: SLA7060MLF210
• Description: UNIPOLAR STEPPER-MOTOR TRANSLATOR/DRIVERS
• Manufacturer: ALLEGRO [Allegro MicroSystems]

Reference voltage. In the Typical Application shown,
resistors R
and REF input current. The sum of R
than 50 k to minimize the effect of I
Minimum output current. The Series SLA7060M uses
fixed off-time PWM current control. Due to internal logic
and switching delays, the actual load current peak will be
slightly higher than the calculated I
for low-inductance loads). These delays, plus the mini-
mum recommended V
current-control circuitry can regulate. An application with
this device should maintain continuous PWM control in
order to obtain optimum torque out of the motor. The
boundary of the load current (I
and discontinuous operation is:
where V
should be pulled above 2 V, turning off all drivers.
Synchronous operation mode. If an external signal
is not available to control the synchronous operation
mode, a simple circuit can keep the SYNC input low while
the CLOCK input is active; the SYNC input will go high
(synchronous operation) when the CLOCK input stays low
(“hold”). The RC time constant determines the sync
trransition timing.
NOTE –The use of this function except at 0, 70.7, or
100%I
recommended.
Temperature effects on FET outputs. Analyzing
safe, reliable operation includes a concern for the relation-
ship of NMOS on resistance to junction temperature.
Device package power calculations must include the
increase in on resistance (producing higher on voltages)
12
SLA7060M
UNIPOLAR STEPPER-MOTOR
TRANSLATOR/DRIVERS
The trimming of R
To produce zero current in a motor, the REF input
I
O(min)
trip
V
R
t
L
max (half-step positions 0 through 8)
off
m
m
M
F
1
= body diode forward voltage
= PWM off time
= motor winding inductance
= motor winding resistance
= [(V
and R
= load supply voltage
V
REF
M
2
set the reference voltage as:
+ V
THRU
=
REF
(V
2
SD
allows for the resistor tolerances
DD
, limit the minimum value the
)/R
x R
m
SLA7062M
] x [(1/e
O(min)
2
)/(R
TRIP
) between continuous
1
1
REF
t off /[R m x L m ]
+ R
+R
value (especially
Applications Information (cont’d)
.
2
2
)
should be less
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
is not
) - 1]
1.6
1.4
1.2
0.8
0.6
0.4
0.2
1
0
-50
-25
Continuous
Normalized FET on resistance
mode
Sync. signal generator
0
Junction temperature in C
25
50
75
Discontinuous
100
mode
125
Io=1.0A
Io=0.7A
Io=0.5A
150