2919
DUAL FULL-BRIDGE
MOTOR DRIVER
2919
The A2919SB and A2919SLB motor drivers are designed to drive
both windings of a bipolar stepper motor or bidirectionally control two dc
motors. Both bridges are capable of sustaining 45 V and include
internal pulse width modulation (PWM) control of the output current to
750 mA. The outputs have been optimized for a low output-saturation
voltage drop (less than 1.8 V total source plus sink at 500 mA).
For PWM current control, the maximum output current is deter-
mined by the user’s selection of a reference voltage and sensing
resistor. Two logic-level inputs select output current limits of 0%, 41%,
67%, or 100% of the maximum level. A PHASE input to each bridge
determines load current direction.
The bridges include both ground clamp and flyback diodes for
protection against inductive transients. Internally generated delays
prevent crossover currents when switching current direction. Special
power-up sequencing is not required. Thermal protection circuitry
disables the outputs if the chip temperature exceeds safe operating
limits.
The A2919SB is supplied in a 24-pin dual in-line plastic batwing
package with a copper lead-frame and heat sinkable tabs for improved
power dissipation capabilities. The A2919SLB is supplied in a 24-lead
surface-mountable SOIC. Their batwing construction provides for
maximum package power dissipation in the smallest possible construc-
tion. The A2919SB/SLB are available for operation from -40°C to
+85°C. To order, change the suffix from 'S–' to 'E–'. These devices are
also available on special order for operation to +125°C. For applica-
tions not requiring quarter-step operation, but desire lower detent or
running current, the similar UDN2916B/EB/LB may be preferred.
DUAL FULL-BRIDGE
PWM MOTOR DRIVER
A2919SB
OUT
1A
OUT
2A
E
2
S E NS E
2
OUT
2B
G R OUND
G R OUND
I
02
Data Sheet
29319.21E
1
2
3
4
5
6
7
8
2
V
BB
24
23
LOAD
S UP P LY
E
1
S E NS E
1
OUT
1B
I
01
G R OUND
G R OUND
I
11
P HAS E
1
V
REF 1
RC
1
LOG IC
S UP P LY
1
22
21
20
19
18
17
P WM 1
I
12
P HAS E
2
V
REF 2
RC
2
9
9
10
11
12
θ
2
P WM 2
θ
1
16
15
14
V
CC
13
Dwg. P P -005
ABSOLUTE MAXIMUM RATINGS
at T
J
≤
150°C
Motor Supply Voltage, V
BB
...................
45 V
Output Current, I
OUT
(Peak, t
w
≤
20 µs) ........................
±1.0 A
(Continuous) ..........................
±750 mA
Logic Supply Voltage, V
CC
..................
7.0 V
Logic Input Voltage Range,
V
IN
.........................
-0.3 V to V
CC
+0.3 V
Output Emitter Voltage, V
E
..................
1.5 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
Output current rating may be limited by duty cycle,
ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified
peak current rating or a junction temperature of
+150°C.
FEATURES
■
■
■
■
■
■
■
750 mA Continuous Output Current
45 V Output Sustaining Voltage
Internal Clamp Diodes
Internal PWM Current Control
Low Output Saturation Voltage
Internal Thermal Shutdown Circuitry
Half- or Quarter-Step Operation of Bipolar Stepper Motors
2919
DUAL FULL-BRIDGE
MOTOR DRIVER
Selection Guide
Part Number
Pb-free
1
R
θJA
(°C/W)
40
55
R
θJT
(°C/W)
6.0
6.0
Package
Packing
Ambient
Temperature
(°C)
–20 to 85
–20 to 85
A2919SLB-T
A2919SLBTR-T
1
Yes
Yes
24-Lead SOIC
24-Lead SOIC
31 per tube
1000 per reel
Pb-based variants are being phased out of the product line. The variants cited in this footnote are in production but have been
determined to be LAST TIME BUY. This classification indicates that sale of this device is currently restricted to existing customer
applications. The variants should not be purchased for new design applications because obsolescence in the near future is
probable. Samples are no longer available. Status change : October 31, 2006. Deadline for receipt of LAST TIME BUY orders:
April 27, 2007. These variants include:
A2919SB, A2919SLB and A2919SLBTR.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
2919
DUAL FULL-BRIDGE
MOTOR DRIVER
A2919SLB
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
5
R
θJT
= 6.0°C/W
I
02
1
PWM 2
24
23
22
2
21
20
19
V
BB
LOAD SUPPLY
OUT
2B
SENSE
2
E
2
OUT
2A
GROUND
GROUND
OUT
1A
E
1
SENSE
1
OUT
1B
I
12
PHASE
2
V
REF 2
RC
2
GROUND
GROUND
LOGIC SUPPLY
RC
1
V
REF 1
PHASE
1
I
11
2
3
4
5
6
7
8
9
9
V
CC
θ
2
4
3
SUFFIX 'B', R
θJA
= 40°C/W
2
18
17
16
1
15
1
SUFFIX 'LB', R
θJA
= 55°C/W
0
25
50
75
100
TEMPERATURE IN
°C
125
150
Dwg. GP-049A
10
PWM 1
11
12
θ
1
14
13
TRUTH TABLE
I
01
PHASE
Dwg. PP-047
OUT
A
H
L
OUT
B
L
H
H
L
PWM CURRENT-CONTROL CIRCUITRY
'B' PACKAGE,
CHANNEL 1
PIN NUMBERS
SHOWN.
V
BB
24
OUT B
1
21
OUT A
V
REF
15
60 kΩ
÷10
120 kΩ
42 kΩ
I
0
20
I
1
17
R
S
23
E
SENSE
–
22
+
ONE
SHOT
14
RC
SOURCE
DISABLE
RC
CC
RT
CT
Dwg. EP-007-3
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
W
Copyright © 1994 Allegro MicroSystems, Inc.
2919
DUAL FULL-BRIDGE
MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at T
A
= +25°C, T
J
≤
150°C, V
BB
= 45 V, V
CC
= 4.75 V to 5.25 V,
V
REF
= 5.0 V (unless otherwise noted).
Limits
Characteristic
Output Drivers (OUT
A
or OUT
B
)
Motor Supply Range
Output Leakage Current
V
BB
I
CEX
Operating
V
OUT
= V
BB
V
OUT
= 0
Output Sustaining Voltage
Output Saturation Voltage
V
CE(sus)
V
CE(SAT)
I
OUT
= ±750 mA, L = 3.0 mH
Sink Driver, I
OUT
= +500 mA
Sink Driver, I
OUT
= +750 mA
Source Driver, I
OUT
= -500 mA
Source Driver, I
OUT
= -750 mA
Clamp Diode Leakage Current
Clamp Diode Forward Voltage
Driver Supply Current
I
R
V
F
I
BB(ON)
I
BB(OFF)
V
R
= 45 V
I
F
= 750 mA
Both Bridges ON, No Load
Both Bridges OFF
10
—
—
45 + V
F
—
—
—
—
—
—
—
—
—
< 1.0
<-1.0
—
0.4
1.0
1.0
1.3
< 1.0
1.6
20
5.0
45
50
-50
—
0.6
1.2
1.2
1.5
50
2.0
25
10
V
µA
µA
V
V
V
V
V
µA
V
mA
mA
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Control Logic
Input Voltage
V
IN(1)
V
IN(0)
Input Current
I
IN(1)
All inputs
All inputs
V
IN
= 2.4 V
V
IN
= 0.8 V
Reference Voltage Range
Current Limit Threshold
(at trip point)
V
REF
V
REF
/ V
SENSE
I
0
= I
1
= 0.8 V, V
REF
= 1.0 V to 7.5 V
I
0
= 2.4 V, I
1
= 0.8 V,
V
REF
= 1.5 V to 7.5 V
I
0
= 0.8 V, I
1
= 2.4 V,
V
REF
= 1.5 V to 7.5 V
Thermal Shutdown Temperature
Total Logic Supply Current
T
J
I
CC(ON)
I
CC(OFF)
Total Reference Current
Fixed Off-Time
I
REF1
+ I
REF2
t
off
I
0
= I
1
= 0.8 V, No Load
I
0
= I
1
= 2.4 V, No Load
V
REF1
= V
REF2
= 7.5 V, I
0
= I
1
= 2.4 V
R
T
= 56 kΩ, C
T
= 820 pF
—
—
—
140
—
170
40
10
185
46
—
50
12
250
—
°C
mA
mA
µA
µs
20.7
24.4
28.0
—
2.4
—
—
—
1.0
9.5
13.5
—
—
<1.0
- 3.0
—
10
15
—
0.8
20
-200
7.5
10.5
16.5
V
V
µA
µA
V
—
—
2919
DUAL FULL-BRIDGE
MOTOR DRIVER
APPLICATIONS INFORMATION
PWM CURRENT CONTROL
The A2919SB/SLB dual bridges are designed to
drive both windings of a bipolar stepper motor. Output
current is sensed and controlled independently in each
bridge by an external sense resistor (R
S
), internal
comparator, and monostable multivibrator.
When the bridge is turned ON, current increases in
the motor winding and flows through the external sense
resistor until the sense voltage (V
S
) reaches the level set
at the comparator’s input:
I
TRIP
= V
REF
/10 R
S
The comparator then triggers the monostable, which
turns OFF the source driver of the bridge. The actual
load current peak will be slightly higher than the trip point
(especially for low-inductance loads) because of the
internal logic and switching delays. This delay (t
d
) is
typically 2 µs. After turn-off, the motor current decays,
circulating through the ground-clamp diode and sink
transistor. The source driver’s OFF time (and therefore
the magnitude of the current decrease) is determined by
the monostable’s external RC timing components, where
t
off
= R
T
C
T
within the range of 20 kΩ to 100 kΩ and
100 pF to 1000 pF.
The fixed-off time should be short enough to keep
the current chopping above the audible range (< 46 µs)
and long enough to properly regulate the current. Be-
cause only slow-decay current control is available, short
off times (< 10 µs) require additional efforts to ensure
proper current regulation. Factors that can negatively
affect the ability to properly regulate the current when
using short off times include: higher motor-supply
voltage, light load, and longer than necessary blank time.
When the source driver is re-enabled, the winding
current (the sense voltage) is again allowed to rise to the
comparator’s threshold. This cycle repeats itself, main-
taining the average motor winding current at the desired
level.
Loads with high distributed capacitances may cause
current spikes capable of tripping the comparator,
resulting in erroneous current control. An external R
C
C
C
time delay should be used to delay the action of the
comparator. Depending on load type, many applications
will not require these external components (SENSE
connected to E).
RS
I
T R IP
PWM OUTPUT CURRENT WAVE FORM
V
P HAS E
+
I
OUT
0
–
t
d
t
off
Dwg. WM-003-1A
LOAD CURRENT PATHS
V
BB
B R IDG E ON
S OUR C E OF F
ALL OF F
Dwg. E P -006-1
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
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