UDN2544B Allegro MicroSystems, Inc., UDN2544B Datasheet - Page 3

• Manufacturer Part Number: UDN2544B
• Description: Quad Darlington Power Driver
• Manufacturer: Allegro MicroSystems, Inc.

1/2
H
H
L
L
INPUTS
V
V
BB
OUT(SAT)
3/4
H
H
L
L
OFF
OFF
ON
ON
A
OFF
OFF
ON
ON
B
WINDINGS
V
BB
+ V + V
ZENER CLAMP
Z
OFF
OFF
ON
ON
C
F
DIODE CLAMP
Dwg. WP-001
V
OFF
OFF
BB
ON
ON
D
+ V
F
motor. Note that with the complimentary control inputs, only two logic
signals are needed to drive the motor in the two-phase format. The two
phase drive format illustrated, energizes two adjacent phases in each
detent position (AB, BC, CD, DA) to provide an improved torque-speed
product and greater detent torque.
increased flyback voltage gives a much faster inductive load turn-OFF
current decay resulting in improved motor performance. The maximum
Zener voltage, plus the load supply voltage, plus the flyback diode
forward voltage must not exceed the device’s rated sustaining voltage.
used for chopper (PWM) applications. If the ENABLE input is not used,
it should be tied low.
A typical application is shown driving a four-phase unipolar stepper
A Zener diode can be used to increase the flyback voltage. The
With external control circuitry, the ENABLE input (active low) can be
All inputs will float high if open circuited.
time, such departures from the detail specifications as may be
required to permit improvements in the design of its products.
reliable. However, Allegro MicroSystems, Inc. assumes no responsi-
bility for its use; nor for any infringements of patents or other rights
of third parties which may result from its use.
Allegro MicroSystems, Inc. reserves the right to make, from time to
The information included herein is believed to be accurate and
QUAD DARLINGTON
POWER DRIVER
2544
Dwg. EP-015