LMD18201T/NOPB National Semiconductor, LMD18201T/NOPB Datasheet - Page 8

• Manufacturer Part Number: LMD18201T/NOPB
• Description: IC H BRIDGE 3A 55V TO220-11
• Manufacturer: National Semiconductor

Specifications of LMD18201T/NOPB

• Applications: DC Motor Driver, Stepper Motor Driver, H Bridge
• Number Of Outputs: 1
• Current - Output: 3A
• Voltage - Supply: 12 V ~ 55 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Through Hole
• Package / Case: TO-220-11 (Bent and Staggered Leads)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Load: -
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device
• Other names: *LMD18201T; *LMD18201T/NOPB; LMD18201T

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Application Information
reverse recovery current of 1A when tested with a full 3A of
forward current through the diode. For the sinking devices
the recovery time is typically 100 ns with 4A of reverse
current under the same conditions.
Typical Applications
BASIC MOTOR DRIVER
The LMD18201 can directly interface to any Sign/Magnitude
PWM controller. The LM629 is a motion control processor
that outputs a Sign/Magnitude PWM signal to coordinate
either positional or velocity control of DC motors. The
LMD18201 provides fully protected motor driver stage.
CURRENT SENSING
In many motor control applications it is desirable to sense
and control the current through the motor. For these types of
applications a companion product, the LMD18200, is also
available. The LMD18200 is identical to the LMD18201 but
has current sensing transistors that output a current directly
proportional to the current conducted by the two upper
DMOS power devices to a separate current sense pin. This
technique does not require a low valued, power sense resis-
tor and does not subtract from the available voltage drive to
the motor.
To sense the bridge current through the LMD18201 requires
the addition of a small sense resistor between the power
ground/sense pin (Pin 7) and the actual circuit ground (see
Figure 8). This resistor should have a value of 0.1Ω or less to
(Continued)
FIGURE 7. Basic Motor Driver
8
stay within the allowable voltage compliance of the sense
pin, particularly at higher operating current levels. The volt-
age between power ground/sense (Pin 7) and the signal
ground (Pin 8) must stay within the range of −1V to +0.5V.
Internally there is approximately 25Ω between pins 7 and 8
and this resistance will slightly reduce the value of the ex-
ternal sense resistor. Approximately 70% of the quiescent
supply current (10 mA) flows out of pin 7. This will cause a
slight offset to the voltage across the sense resistor when
the bridge is not conducting. During reverse recovery of the
internal protection diodes the voltage compliance between
pins 7 and 8 may be exceeded. The duration of these spikes
however are only approximately 100 ns and do not have
enough time or energy to disrupt the operation of the
LMD18201.
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