MC33394DWB Freescale Semiconductor, MC33394DWB Datasheet - Page 19

• Manufacturer Part Number: MC33394DWB
• Description: IC POWER SUPPLY MULT-OUT 54-SOIC
• Manufacturer: Freescale Semiconductor

Specifications of MC33394DWB

• Applications: Motorola MPC55x, MPC56x Microprocessors
• Interface: SPI Serial
• Voltage - Supply: 4 V ~ 26.5 V
• Package / Case: 54-SOIC (0.300", 7.50mm Width) Exposed Pad
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

the trip–off temperature. The output will periodically turn on
and off until either the die temperature decreases or until the
fault condition is removed. If the VSEN output goes into
over—temperature shutdown, it does not impact the operation
of any of the other outputs (assuming that no other package
thermal or VPRE current limit specifications are violated).
Fault information is reported through the SPI communication
interface (see Figure 8).
4.10. Resets To Microprocessor
/HRESET– Hardware Reset. All the Reset pins are open drain
‘active low’ outputs, capable of sinking 1.0 mA current and
able to withstand +7.0 V. See Figure 1 and Figure 20 for
recommended pull–up resistor values and their connection.
pull up resistor. It is connected to the microprocessor Power
On Reset (POR) pin, and is normally high. During initial battery
connect the /PORESET is held to ground by the 33394. After
the VKAM supply is in regulation and an internal 10 ms timer
has expired, the /PORESET is released. If VKAM goes out of
regulation the device will first pull the /PORESET and
/PRERESET followed by a 0.7 s delay then /HRESET. By
/HRESET low VDDH, VDD3_3 and VDDL will start a power
down sequence. When the fault is removed a standard power
up sequence is initiated. The VKAM linear regulator output
must be out of regulation for greater than 20
/PORERSET and /PRERESET (with /HRESET 0.7
delayed) are pulled low. If a fault occurs on VKAM in the
Key–Off Mode (when the VIGN is off) and the fault is then
removed the VKAM will regulate but /PORESET will not be
released until Key–On (asserting VIGN pin) allows the 10 ms
timer to run.
asserted when the 33394 enters Sleep Mode by asserting the
/SLEEP pin. When exiting out of Sleep Mode the 33394
asserts the Resets (/PRERESET, /HRESET) during the power
up sequence.
VKAM (see Figure 1) or to VDDL (see Figure 20). Refer to
section 5. Application Information, paragraph 5.3.
Selecting Pull–Up Resistors for detailed description of
these two connection scenarios. The 33394 monitors the main
supply voltages VDDH, VDD3_3 and VDDL. If any of these
voltages falls out of regulation limits the /PRERESET will be
pulled down followed by the /HRESET after 0.7 s delay, and
the power down sequence will be initiated. There are several
different scenarios how to connect the /PRERESET and
/HRESET pins to the microprocessor. Typically the
/PRERESET pin will be connected to the IRQ0 pin of the
microprocessor, and the /HRESET to the microprocessor
/HRESET pin (see Figure 5). The VDDH, VDD3_3 and VDDL
linear regulator outputs must be out of regulation for greater
than 20
delayed) are pulled low.
4.11. Hardware Reset Timer (HRT)
VDD3_3 and VDDL active and stable and the release of the
/HRESET and /PRERESET outputs. An external resistor and
MOTOROLA ANALOG INTEGRATED CIRCUIT DEVICE DATA
/PORESET – Power On Reset, /PRERESET — Pre Reset,
The /PORESET pin is pulled up to the VKAM voltage by a
The Reset signals (/PRERESET, /HRESET) are not
The /PRERESET and /HRESET pins are pulled up to the
The HRT pin is used to set the delay between VDDH,
s before /PRERESET (with /HRESET 0.7
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s before
33394
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capacitor is used to program the timer. To minimize quiescent
current during power down modes, the RC timer current
should be drawn from one of the VDD supplies (see Figure 1).
The threshold on the HRT pin has zero temperature coefficient
and is set at 2.5 V.
4.12. Power Up/Down Sequencing
meet the power up and power down requirements of the
MPC565 microprocessor. The MPC565 processor requires
that VDDH remain within 3.1 volts of VDDL during power up
and can not lag VDDL by more than 0.5 volts. This condition
is met by the 33394 regardless of load impedance. It is critical
to note that the 33394 under normal conditions is designed to
supply VKAM prior to the power up sequence on VDDH,
VDD3_3 and VDDL. During power up and power down
sequencing /PRERESET and /HRESET are held low. Power
up and power down sequencing is implemented in six steps.
During this process the reference voltage for VDDH, VDD3_3
and VDDL is ramped up in six steps. Minimum power up/down
time is dependent on the internal clock and is 800
Maximum power up/down time is also dependent on load
impedance. During the power up/down cycle, voltage level
requirements for each step of VDDH, VDD3_3 and VDDL
must be met before the supply may advance to the next
voltage level. Hence VDDH and VDDL will remain within the
3.1/0.5 V window. Figure 6 illustrates a typical power up and
down sequence.
4.13. Regulator Enable Function (REGON)
shut down of the 33394 device. It holds off the activation of the
Reset signals, to the microcontroller, after the VIGN signal has
transitioned and signals the request to shutdown the VDDH,
VDD3_3, VDDL, VSEN and the VREFn supplies. This allows
the microcontroller to delay a variable amount of time, after
sensing that the VIGN signal has transitioned and signaled the
request to shutdown the regulated supplies. This time can be
used to store data to EPROM memory, schedule an orderly
shutdown of peripherals, etc. The microcontroller can then
drive the REGON signal, to the 33394, to the low logic state,
to turn off the regulators (except for the VKAM supply).
4.14. Regulator Shutdown Function (/SLEEP)
microprocessor) to shut down the 33394 regulators, even if
the VIGN signal (or REGON) is active, by asserting the
/SLEEP pin from high to low (falling edge transition). In this
case the 33394 initiates the power down sequence, but the
Reset signals (/PRERESET, /HRESET) are not asserted. This
allows the microprocessor to continue to execute code when
it is supplied only from the Keep Alive supply VKAM. When the
microprocessor exits sleep state by pulling /SLEEP pin high
the Resets (/PRERESET, /HRESET) are asserted during the
power up sequence.
its functionality is not used this pin can be either pulled up to
VKAM, VBAT, pulled down to ground or left open.
The 33394 power up sequence is specifically designed to
This feature allows the microcontroller to select the delayed
This feature allows for an external control element (e.g.
The /SLEEP pin has an internal pull down, therefore when
The /SLEEP pin should not be pulled up to VDDH.
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s.