MC33888FB Freescale, MC33888FB Datasheet - Page 16

• Manufacturer Part Number: MC33888FB
• Manufacturer: Freescale

Specifications of MC33888FB

• Switch Type: High Side
• Power Switch Family: MC33888FB
• Input Voltage: 6 to 27V
• Power Switch On Resistance: 100mOhm
• Output Current: 10A
• Number Of Outputs: 4
• Mounting: Surface Mount
• Supply Current: 20mA
• Package Type: PQFP
• Operating Temperature (min): -40C
• Operating Temperature (max): 150C
• Operating Temperature Classification: Automotive
• Pin Count: 64
• Lead Free Status / RoHS Status: Compliant

by a logic H for each output in the QHSOLSS status word (TABLE 3).
output will be cleared by a rising edge on CSB.
The FLTB pin is driven to a logic L when a fault exists on any of the outputs. FLTB provided real time monitoring of the over-
voltage fault. For the high side outputs, FLTB provides real time monitoring of the open-load and over-temp. For the low side
outputs, the FLTB is latched to a logic L for open-load, over-temp, and over-current faults. The latch is cleared by toggling the
state of the faulted output or by brinding RSTB low.
OVER-TEMPERATURE FAULT REQUIREMENTS
The QHSOLSS incorporates over-temperature detection and shutdown circuitry into each individual output structure. Over-
temperature detection occurs when an output is in the on state. When an output is shutdown, due to an over-temperature
condition, no other outputs is affected. The output experiencing the fault, is shutdown to protect itself from damage. A fault bit is
loaded into the status register if the over-temp condition is removed, the fault bit is cleared upon the rising edge of CSB.
For the LS outputs, the faulted output is latched OFF during an over-temp condition. If the temperature falls below the recovery
level, “TLIM(hyst)”, then the output can be turned back ON only after the output has first been commanded OFF either through
the SPI or the ILS, depending on the logic configuration.
For the HS output(s), an over-temperature condition will result in the output(s) turning OFF until the temperature falls below the
TLIM(hyst). This cycle will continue indefinitely until action is taken by the master to shut the output(s) OFF.
OVER-VOLTAGE FAULT REQUIREMENTS
The QHSOLSS do shutdown all outputs during an over-voltage condition on the VPWR pin. The outputs remain in the off state,
until the over-voltage condition is removed. Fault status for all outputs is latched into the status register. Following an over-
voltage condition, the next write cycle sent by the SO pin of the QHSOLSS is logic H on OD0-OD11, indicating all outputs have
shutdown. If the over-voltage condition is removed, the status register can be cleared by a rising edge on CSB.
OPEN LOAD FAULT
The QHSOLSS incorporates open-load detection circuitry on every output. A HS or LS Output Open Load Fault is detected and
reported as a fault condition when the corresponding output is disabled (OFF) if it was configured for open load detection by
setting the appropriate bit to logic L (HS0-HS3), or logic H (LS4-LS11) in the OLFCR register.
The HS open load fault is detected and latched into the status register after the internal gate voltage is pulled low enough to turn
off the output. If the open load fault is removed or if the faulted output is commanded ON, the status register can be cleared by a
rising edge on CSB. Note that the device default state will enable the HS open load detection and disable the LS open load
detection circuits, respectively.
OVER-CURRENT FAULT REQUIREMENTS: LS OUTPUT
An over-current condition is defined as any current value greater than ILIM (500mA min value)for LS5, 7, 9, 11 and 800mA min
value for LS4, 6, 8, 10). The status of the corresponding bit in the CLOCCR register determines whether a specific output will
shutdown, or will continue to operate in an analog current limited mode, until either the over-current condition is removed or the
thermal shutdown limit is reached (see Figure3). If the over-current shutdown mode is disabled, the fault reporting is disabled as
well.
For the LS output of interest, if a D4-D11 bit was set to a logic H in the OLCR register, the over-current protection shutdown
circuitry will be enabled for that output. When a low side output is commanded ON either from the SPI or the ILS pin, the drain of
the low side driver will be monitored for a voltage greater than the Fault Detect Threshold (3V typ). If the drain voltage exceeds
this threshold, a timer will start and the output will be turned off and a fault latched in the status register after the timeout expires.
The faulted output can be retried only by commanding the output OFF and back ON either through the SPI or the ILS pin,
depending on the logic configuration. If the fault is gone, the retried output will return to normal operation and the status register
L OW =
Quad High Side and Octal Low Side Switch for Automotive
Freescale Semiconductor, Inc.
For More Information On This Product,
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Figure 3. LS Output OFF Open Load Detect
Go to: www.freescale.com
DEVICE DESCRIPTION
Q H SO LSS D E VIC E
MC33888FB
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