A3980KLP-T Allegro Microsystems Inc, A3980KLP-T Datasheet - Page 14

• Manufacturer Part Number: A3980KLP-T
• Description: IC MOTOR DRIVER MICROSTEP 28-TSS
• Manufacturer: Allegro Microsystems Inc

Specifications of A3980KLP-T

• Applications: Stepper Motor Driver
• Number Of Outputs: 1
• Current - Output: ± 1A
• Voltage - Load: 7 V ~ 50 V
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 28-TSSOP Exposed Pad, 28-eTSSOP, 28-HTSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 620-1081

A3980
The A3980 is a power circuit, therefore careful consider-
ation must be given to power dissipation and the effects
of high currents on interconnect and supply wiring.
Power Dissipation. A fi rst order approximation of
the power dissipation in the A3980 can be determined
by examining the power dissipation in each of the
two full-bridges during each of the operation modes.
When synchronous rectifi cation is used, current fl ow
most of the time through the DMOS FETs that are
switched on. When synchronous rectifi cation is not
used, the current fl ows through the body diode of
the DMOS FETs during the decay phase. The use of
fast or slow decay also affects the dissipation. All the
above combinations can be calculated from fi ve basic
DMOS output states, shown in the following illustrations.
Both low-side DMOS output
transistors are on. Current circu-
lates through both transistors and
the load.
Dissipation is I
DMOS transistors:
Diagonally opposite DMOS output
transistors are on. Current fl ows
from ground through load to posi-
tive supply.
Dissipation is I
DMOS transistors:
P
Synchronous Slow Decay
Synchronous Fast Decay
SF
P
= I
SS
2
= I
(R
2
DSONH
(2
2
×
2
R losses in the
R losses in the
R
+ R
DSONL
DSONL
)
)
Application Information
Automotive DMOS Microstepping Driver
M
M
+
+
M
M
M
+
+
+
One low-side DMOS output tran-
sistor and one body diode conduct-
ing. Current circulates through the
diode, the transistor, and the load.
Dissipation is I
DMOS transistors plus IV loss in
the diode:
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Diagonally opposite body diodes
conducting. Current fl ows from
ground through load to positive
supply.
Dissipation is IV losses in the
diodes:
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
Diagonally opposite DMOS
output transistors are on. Cur-
rent fl ows from positive supply
through load to ground. Used in
all combinations.
Dissipation is I
DMOS transistors:
Non-Synchronous Slow Decay
P
Non-Synchronous Fast Decay
NS
P
D
= (I
Drive Current Ramp
= I
with Translator
P
NF
2
2
×
(R
= I (V
R
DSONH
DSONL
2
R losses in the
2
R losses in the
FH
+ R
+ V
) + (I
DSONL
Fl
)
×
V
)
F
)
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