LMD18201T National Semiconductor, LMD18201T Datasheet - Page 5

• Manufacturer Part Number: LMD18201T
• Description: IC, MOTOR CTRL, HALF BRIDGE 3A TO-220-11
• Manufacturer: National Semiconductor

Specifications of LMD18201T

• Motor Type: Half Bridge
• No. Of Outputs: 2
• Output Current: 3A
• Supply Voltage Range: 12V To 55V
• Driver Case Style: TO-220
• No. Of Pins: 11
• Operating Temperature Range: -40°C To +125°C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Test Circuit
Switching Time Definitions
Pinout Descriptions
(See Connection Diagram)
Pin 1, BOOTSTRAP 1 Input: Bootstrap capacitor pin for half
H-Bridge number 1. The recommended capacitor (10 nF) is
connected between pins 1 and 2.
Pin 2, OUTPUT 1: Half H-Bridge number 1 output.
Pin 3, DIRECTION Input: See
the direction of current flow between OUTPUT 1 and OUT-
PUT 2 (pins 2 and 10) and, therefore, the direction of rotation
of a motor load.
Pin 4, BRAKE Input: See
a motor by effectively shorting its terminals. When braking is
Table
1. This input is used to brake
Table
1. This input controls
1079309
1079308
5
desired, this input is taken to a logic high level and it is also
necessary to apply logic high to PWM input, pin 5. The drivers
that short the motor are determined by the logic level at the
DIRECTION input (Pin 3): with Pin 3 logic high, both current
sourcing output transistors are ON; with Pin 3 logic low, both
current sinking output transistors are ON. All output transis-
tors can be turned OFF by applying a logic high to Pin 4 and
a logic low to PWM input Pin 5; in this case only a small bias
current (approximately −1.5 mA) exists at each output pin.
Pin 5, PWM Input: See
TION input, Pin 3) is used is determined by the format of the
PWM Signal.
Pin 6, V
Pin 7, POWER GROUND/SENSE Connection: This pin is
the ground return for the power DMOS transistors of the H-
Bridge. The current through the H-Bridge can be sensed by
adding a small, 0.1Ω, sense resistor from this pin to the power
supply ground.
Pin 8, SIGNAL GROUND: This is the ground return for the
internal logic circuitry used to control the PWM switching of
the H-Bridge.
Pin 9, THERMAL FLAG Output: This pin provides the ther-
mal warning flag output signal. Pin 9 becomes active-low at
145°C (junction temperature). However the chip will not shut
itself down until 170°C is reached at the junction.
Pin 10, OUTPUT 2: Half H-Bridge number 2 output.
Pin 11, BOOTSTRAP 2 Input: Bootstrap capacitor pin for half
H-Bridge number 2. The recommended capacitor (10 nF) is
connected between pins 10 and 11.
Application Information
TYPES OF PWM SIGNALS
The LMD18201 readily interfaces with different forms of PWM
signals. Use of the part with two of the more popular forms of
PWM is described in the following paragraphs.
Simple, locked anti-phase PWM consists of a single, vari-
able duty-cycle signal in which is encoded both direction and
amplitude information (see
signal represents zero drive, since the net value of voltage
(integrated over one period) delivered to the load is zero. For
the LMD18201, the PWM signal drives the direction input (pin
3) and the PWM input (pin 5) is tied to logic high.
PWM
H
H
H
H
L
L
S
Power Supply
Dir
H
X
H
X
L
L
TABLE 1. Logic Truth Table
Brake
H
H
H
L
L
L
Table
Figure
1. How this input (and DIREC-
Source 1, Sink 2
Sink 1, Source 2
Source 1, Source 2
Source 1, Source 2
Sink 1, Sink 2
NONE
Active Output Drivers
2). A 50% duty-cycle PWM
www.national.com