MC35XS3400 Datasheet, PDF (25/45 Pages) Freescale Semiconductor, Inc – Quad High Side Switch (Quad 35mΩ)

FUNCTIONAL DEVICE OPERATION
PROTECTION AND DIAGNOSTIC FEATURES
The SPI fault report (SC[0:3] bits) is removed after a read
operation.
Over-voltage Fault (Enabled by default)
By default, the over-voltage protection is enabled. The
35XS3400 shuts down all outputs and FS will go to logic [0]
during an over-voltage fault condition on the VPWR pin
(V_PWR > V_PWR(OV)). The outputs remain in the OFF state until
the over-voltage condition is removed (V_PWR < V_PWR(OV) -
V_PWR(OVHYS)). When experiencing this fault, the OVF fault bit
is set to logic [1] and cleared after either a valid SPI read.
The over-voltage protection can be disabled through SPI
(OV_dis bit is disabled set to logic [1]). The fault register
reflects any over-voltage condition (V_PWR > V_PWR(OV)). This
over-voltage diagnosis, as a warning, is removed after a read
operation, if the fault condition disappears. The HS[0:3]
outputs are not commanded in R_DS(ON) above the OV
threshold.
In Fail-safe mode, the over-voltage activation depends on
the RST logic state; enable for RST = 1 and disable for
RST = 0. The device is still protected with over-temperature
protection in case the over-voltage feature is disabled.
Under-voltage Fault
The output(s) will latch off at some battery voltage below
VPWR_(UV). As long as the V_DD level stays within the normal
specified range, the internal logic states within the device will
remain (configuration and reporting).
In the case where battery voltage drops below the under-
voltage threshold (V_PWR < V_PWR(UV)), the outputs will turn off,
FS will go to logic [0], and the fault register UV bit will be set
to [1].
Two cases need to be considered when the battery level
recovers (V_PWR > V_{PWR(UV)_UP}):
•If the output command is OFF, FS will go to logic [1], but
the UV bit will remain set to 1 until the next read
operation (warning report).
•If the output command is ON, FS will remain at logic [0].
To delatch the fault and be able to turn ON again the
outputs, the failure condition must disappear and the
autoretry circuitry must be active or the corresponding
output must be commanded OFF and then ON (toggling
fault_control signal of corresponding output) or
V_SUPPLY(POR) condition if V_DD = 0.
In extended mode, the output is protected by over-
temperature shutdown circuitry. All previous latched faults,
occurred when VPWR was within the normal voltage range,
are guaranteed if VDD is within the operational voltage range
or until V_SUPPLY(POR) if VDD = 0. Any new OT fault is
detected (VDD failure included) and reported through SPI
above VPWR_(UV). The output state is not changed as long as
the VPWR voltage does not drop any lower than 3.5V typical.
All latched faults (over-temperature, over-current, severe
short-circuit, over and under-voltage) are reset if:
• V_DD < V_DD(FAIL) with V_PWR in nominal voltage range,
•V_DD and V_PWR supplies is below V_SUPPLY(POR) voltage
value.
Analog Integrated Circuit Device Data
Freescale Semiconductor
35XS3400
25