LMD18201T/NOPB National Semiconductor, LMD18201T/NOPB Datasheet - Page 6

• 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
Sign/magnitude PWM consists of separate direction (sign)
and amplitude (magnitude) signals (see Figure 3). The (ab-
solute) magnitude signal is duty-cycle modulated, and the
SIGNAL TRANSITION REQUIREMENTS
To ensure proper internal logic performance, it is good prac-
tice to avoid aligning the falling and rising edges of input
signals. A delay of at least 1 µsec should be incorporated
between transitions of the Direction, Brake, and/or PWM
input signals. A conservative approach is be sure there is at
least 500ns delay between the end of the first transition and
the beginning of the second transition. See Figure 4.
USING THE THERMAL WARNING FLAG
The THERMAL FLAG output (pin 9) is an open collector
transistor. This permits a wired OR connection of thermal
warning flag outputs from multiple LMD18201’s, and allows
the user to set the logic high level of the output signal swing
to match system requirements. This output typically drives
FIGURE 4. Transitions in Brake, Direction, or PWM Must be Separated by At Least 1 µsec
FIGURE 3. Sign/Magnitude PWM Control
(Continued)
6
absence of a pulse signal (a continuous logic low level)
represents zero drive. Current delivered to the load is pro-
portional to pulse width. For the LMD18201, the DIRECTION
input (pin 3) is driven by the sign signal and the PWM input
(pin 5) is driven by the magnitude signal.
the interrupt input of a system controller. The interrupt ser-
vice routine would then be designed to take appropriate
steps, such as reducing load currents or initiating an orderly
system shutdown. The maximum voltage compliance on the
flag pin is 12V.
SUPPLY BYPASSING
During switching transitions the levels of fast current
changes experienced may cause troublesome voltage tran-
sients across system stray inductances.
It is normally necessary to bypass the supply rail with a high
quality capacitor(s) connected as close as possible to the V
Power Supply (Pin 6) and POWER GROUND (Pin 7). A 1 µF
high-frequency ceramic capacitor is recommended. Care
should be taken to limit the transients on the supply pin
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