33886_07 Datasheet, PDF (17/25 Pages) Freescale Semiconductor, Inc – 5.0 A H-Bridge

FUNCTIONAL DEVICE OPERATION
FUNCTIONAL PIN DESCRIPTION
FUNCTIONAL DEVICE OPERATION
SHORT CIRCUIT PROTECTION
If an output short circuit condition is detected, the power
outputs tri-state (latch-OFF) independent of the input (IN1
and IN2) states, and the fault status output flag is set logic
Low. If the D1 input changes from logic High to logic Low, or
if the D2 input changes from logic Low to logic High, the
output bridge will become operational again and the fault
status flag will be reset (cleared) to a logic High state.
The output stage will always switch into the mode defined
by the input pins (IN1, IN2, D1, and D2), provided the device
junction temperature is within the specified operating
temperature.
ACTIVE CURRENT LIMITING
The maximum current flow under normal operating
conditions is internally limited to I_LIM (5.2 A to 7.8 A). When
the maximum current value is reached, the output stages are
tri-stated for a fixed time (t _a) of 20 µs typical. Depending on
the time constant associated with the load characteristics, the
current decreases during the tri-state duration until the next
output ON cycle occurs (see Figures 9 and 12, page 9 and
page 10, respectively).
The current limiting threshold value is dependent upon the
device junction temperature. When -40°C < T_J < 160°C, I_LIM
is between 5.2 A and 7.8 A. When T_J exceeds 160°C, the I_LIM
current decreases linearly down to 2.5 A typical at 175°C.
Above 175°C the device overtemperature circuit detects T_LIM
and overtemperature shutdown occurs (see Figure 7,
page 8). This feature allows the device to remain operational
for a longer time but at a regressing output performance level
at junction temperatures above 160°C.
OVERTEMPERATURE SHUTDOWN AND
HYSTERESIS
If an overtemperature condition occurs, the power outputs
are tri-state (latched-OFF) independent of the input signals
and the fault status flag is set logic Low.
To reset from this condition, D1 must change from logic
High to logic Low, or D2 must change from logic Low to logic
High. When reset, the output stage switches ON again,
provided that the junction temperature is now below the
overtemperature threshold limit minus the hysteresis.
Note Resetting from the fault condition will clear the fault
status flag.
MAIN DIFFERENCES COMPARED TO
MC33186DH1
• COD pin has been removed. Pin 8 is now a Do Not
Connect (DNC) pin.
• Pin 20 is no longer connected in the 20 HSOP package. It
is now a DNC pin.
• R_DS(ON) max at T_J = 150°C is now 225 mΩ per each output
transistor.
• Maximum temperature operation is now 160°C, as
minimum thermal shutdown temperature has increased.
• Current regulation limiting foldback is implemented above
160°C T_J.
• Thermal resistance junction to case has been increased
from ~2.0°C/W to ~5.0°C/W.
Analog Integrated Circuit Device Data
Freescale Semiconductor
33886
17