Datasheet

LMD18245
www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013
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
comparator triggers the monostable.
Pin 3, RC: Monostable timing node. A parallel resistorcapacitor 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 provides 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 SWITCH CONTROL LOGIC TRUTH 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 SWITCH CONTROL LOGIC TRUTH 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
×
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.
SWITCH CONTROL LOGIC TRUTH TABLE
(1)
BRAKE DIRECTION MONO Active Switches
H X X Source 1, Source 2
L H L Source 2
L H H Source 2, Sink 1
L L L Source 1
L L H Source 1, Sink 2
(1) X = don't care. MONO is the output of the monostable.
(1) X = don't care. MONO is the output of the monostable.
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