Discontinued Product
For Reference Only
Combining logic gates and high-current bipolar outputs, the
UDN2544B quad Darlington power driver provides an interface be-
tween low-level logic circuitry and high-power loads. Each of the four
outputs can sink up to 1.8 A in the on state with peak inrush currents
to 2.5 A. The four power outputs are each comprised of an open-
collector Darlington driver and an internal flyback/clamp diode for
switching inductive loads. They feature a minimum breakdown and
sustaining voltage of 50 V. The logic inputs are compatible with TTL
and 5 V CMOS logic systems.
This device is particularly well-suited for unipolar stepper motor
drive applications. With complementary control inputs and an active-
low ENABLE, the UDN2544B makes it easy to implement full stepping
of a stepper motor with only two microcontroller/microprocessor control
lines. Other typical applications include relay or solenoid driving and
incandescent or LED lamp driving.
The UDN2544B is supplied in a 16-pin batwing power DIP. The
batwing construction provides for maximum package power dissipation
in a standard DIP construction. At 25
C, and with only 1 sq. in. of
copper foil at the ground tabs, the package is capable of safely dissi-
pating 3.8 W.
QUAD DARLINGTON
POWER DRIVER
FEATURES
s
1.8 A Continuous Output Current
s
Output Voltage to 50 V
s
Inputs Configured for Unipolar Stepper Motors
s
Active-Low Output Enable
s
TTL and 5 V CMOS Compatible Inputs
s
Integral Transient-Suppression Diodes
Always order by complete part number:
UDN2544B .
ABSOLUTE MAXIMUM RATINGS
at T
A
= 25
C
Output Voltage, V
OUT
............................. 50 V
Output Current, I
OUT
(Peak) ........................................... 2.5 A
(Continuous) ................................. 1.8 A
Logic Supply Voltage, V
CC
.................... 7.0 V
Input Voltage, V
IN
.................................. 7.0 V
Package Power Dissipation,
P
D
......................................... See Graph
Operating Temperature Range,
T
A
.................................. -20
C to +85
C
Storage Temperature Range,
T
S
................................ -55
C to +150
C
2544
Data Sheet
29317.6
1
2
3
14
4
5
6
7
8
9
10
11
12
13
15
16
ENABLE
GROUND
GROUND
OUT
2
K
GROUND
GROUND
OUT
3
OUT
4
K
OUT
1
V
CC
IN
1
Dwg. PP-017A
IN
4
IN
3
IN
2
2544
QUAD DARLINGTON
POWER DRIVER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Output Leakage Current
I
CEX
V
OUT
= 50 V
--
<1.0
100
A
Output Sustaining Voltage
V
CE(sus)
I
OUT
= 1.8 A, L = 3.0 mH
50
--
--
V
Output Saturation Voltage
V
CE(SAT)
I
OUT
= 600 mA
--
0.9
1.0
V
I
OUT
= 1.0 A
--
1.0
1.2
V
I
OUT
= 1.8 A
--
1.3
1.6
V
Input Voltage
Logic 1
V
IN(1) or
V
EN(1)
2.4
--
--
V
Logic 0
V
IN(0) or
V
EN(0)
--
--
0.8
V
Input Current
Logic 1
V
IN(1) or
V
EN(1)
= 2.4 V
--
--
10
A
Logic 0
V
IN(0) or
V
EN(0)
= 0.8 V
--
--
-100
A
Total Supply Current
I
CC
All Outputs ON, Outputs Open
--
14
20
mA
All Outputs OFF
--
0.4
2.0
mA
Clamp Diode Forward Voltage
V
F
I
F
= 1.0 A
--
1.3
1.6
V
I
F
= 1.8 A
--
1.6
2.0
V
Clamp Diode Leakage Current
I
R
V
R
= 50 V
--
< 1.0
100
A
Typical Data is for design information only.
Negative current is defined as coming out of (sourcing) the specified terminal.
As used here, -100 is defined as greater than +10 (absolute magnitude convention) and the minimum is implicitly zero.
ELECTRICAL CHARACTERISTICS at T
A
= +25
C, T
J
150
C, V
CC
= 4.75 V to 5.25 V.
TRUTH TABLE
ENABLE
IN
1
OUT
1
IN
2
OUT
2
IN
3
OUT
3
IN
4
OUT
4
L
H
ON
H
OFF
H
OFF
H
ON
L
OFF
L
ON
L
ON
L
OFF
H
X
OFF
X
OFF
X
OFF
X
OFF
X = Don't care
W
Copyright 1989, 2001 Allegro MicroSystems, Inc.
50
75
100
125
150
3
2
1
0
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
TEMPERATURE IN
C
4
25
Dwg. GP-010B
5
R = 43
C/W
JA
R = 6.0
C/W
JT
2544
QUAD DARLINGTON
POWER DRIVER
APPLICATIONS INFORMATION
A typical application is shown driving a four-phase unipolar stepper
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.
A Zener diode can be used to increase the flyback voltage. The
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.
With external control circuitry, the ENABLE input (active low) can be
used for chopper (PWM) applications. If the ENABLE input is not used,
it should be tied low.
All inputs will float high if open circuited.
TRUTH TABLE
INPUTS
WINDINGS
1/2
3/4
A
B
C
D
L
H
ON
ON
OFF
OFF
L
L
OFF
ON
ON
OFF
H
L
OFF
OFF
ON
ON
H
H
ON
OFF
OFF
ON
OUTPUT
VOLTAGE
OUTPUT
CURRENT
ZENER CLAMP
DIODE CLAMP
V
BB
V
OUT(SAT)
V + V
BB
F
V + V + V
BB
Z
F
TYPICAL APPLICATION
(UNIPOLAR STEPPER MOTOR WITH ZENER FLYBACK)
Dwg. EP-015
Dwg. WP-001
Allegro MicroSystems, Inc. reserves the right to make, from time to
time, such departures from the detail specifications as may be
required to permit improvements in the design of its products.
The information included herein is believed to be accurate and
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.
2544
QUAD DARLINGTON
POWER DRIVER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Dimensions in Millimeters
(for reference only)
Dimensions in Inches
(controlling dimensions)
0.020
0.008
0.300
BSC
Dwg. MA-001-17A in
0.430
MAX
16
1
8
0.280
0.240
0.210
MAX
0.070
0.045
0.015
MIN
0.022
0.014
0.100
BSC
0.005
MIN
0.150
0.115
9
0.775
0.735
NOTE 4
NOTES: 1. Leads 1, 8, 9, and 16 may be half leads at vendor's option.
2. Lead thickness is measured at seating plane or below.
3. Lead spacing tolerance is non-cumulative.
4. Webbed lead frame. Leads indicated are internally one piece.
5. Exact body and lead configuration at vendor's option within limits shown.
0.508
0.204
7.62
BSC
Dwg. MA-001-17A mm
10.92
MAX
16
1
8
7.11
6.10
5.33
MAX
1.77
1.15
0.39
MIN
0.558
0.356
2.54
BSC
0.13
MIN
3.81
2.93
9
19.68
18.67
NOTE 4
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