LMD18245 datasheet(2/21 Pages) NSC

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Connection Diagram

01187802

Top View

15-Lead TO-220 Molded Power Package

Order Number LMD18245T

See NS Package Number TA15A

Pinout Descriptions (See Functional Block

and Connection Diagrams)

Pin 1, OUT 1: Output node of the first half H-bridge.

Pin 2, COMP OUT: Output of the comparator. If the voltage

at CS OUT exceeds that provided by the DAC, the compara-

tor triggers the monostable.

Pin 3, RC: Monostable timing node. A parallel resistorca-

pacitor network connected between this node and ground

sets the monostable timing pulse at about 1.1 RC seconds.

Pin 5, PGND: Ground return node of the power bridge. Bond

wires (internaI) connect PGND to the tab of the TO-220

package.

Pins 4 and 6 through 8, M4 through M1: Digital inputs of

the DAC. These inputs make up a four-bit binary number

with M4 as the most significant bit or MSB. The DAC pro-

vides an analog voltage directly proportional to the binary

number applied at M4 through M1.

Pin 9, V

CC: Power supply node.

Pin 10, BRAKE: Brake logic input. Pulling the BRAKE input

logic-high activates both sourcing switches of the power

bridge — effectively shorting the load. See Table 1. Shorting

the load in this manner forces the load current to recirculate

and decay to zero.

Pin 11, DIRECTION: Direction logic input. The logic level at

this input dictates the direction of current flow in the load.

See Table 1.

Pin 12, SGND: Ground return node of all signal level circuits.

Pin 13, CS OUT: Output of the current sense amplifier. The

current sense amplifier sources 250 µA (typical) per ampere

of total forward current conducted by the upper two switches

of the power bridge.

Pin 14, DAC REF: Voltage reference input of the DAC. The

DAC provides an analog voltage equal to V

DAC REF x D/16,

where D is the decimal equivalent (0–15) of the binary

number applied at M4 through M1.

Pin 15, OUT 2: Output node of the second half H-bridge.

TABLE 1. Switch Control Logic Truth Table

BRAKE

DIRECTION

MONO

Active Switches

Source 1, Source 2

Source 2

Source 2, Sink 1

Source 1

Source 1, Sink 2

X = don’t care

MONO is the output of the monostable.

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