Chapter 34 Voltage Regulators and Power Supplies
MPC5602P Microcontroller Reference Manual, Rev. 4
Freescale Semiconductor
849
Chapter 34
Voltage Regulators and Power Supplies
34.1
Voltage regulator
The power blocks are used for providing 1.2 V digital supply to the internal logic of the device. The
main/input supply is 3.3 V to 5.0 V ±10% and the digital/regulated output supply has a trim target voltage
of 1.28 V. The voltage regulator used in MPC5602P is the high power or main regulator (HPREG).
The internal voltage regulator requires an external ballast transistor and (external) capacitance (CREG) to
be connected to the device in order to provide a stable low voltage digital supply to the device.
Capacitances should be placed on the board as near as possible from the associated pins.The regulator has
a digital domain called the High Power domain that has a low voltage detector for the 1.2 V output voltage.
Additionally, there are two low voltage detectors for the main/input supply with different threshold, one at
3.3 V level and the other one at 5 V level.
34.1.1
High Power or Main Regulator (HPREG)
The HPREG converts the 3.3 V–5 V input supply to a 1.2 V digital supply. The nominal target output is
1.28 V. Due to all variations, the actual output will be in range of 1.08 V to 1.32 V in the full current load
range (0–250 mA) after trimming.
The stabilization for HPREG is achieved using an external capacitance. The minimum recommended
value is 3 × 10 µF with low ESR (refer to datasheet for details).
NOTE
In general an offset voltage must be avoided to pre-charge V
DD_HV_REG
through parasitic paths to allow a correct power up sequence.
The MCU supply must power on from GND to power supply with a
monotonic ramp, minimum and maximum values as described in the data
sheet (TV
DD
).
34.1.2
Low Voltage Detectors (LVD) and Power On Reset (POR)
Five types of low voltage detectors are provided on the device:
•
V
REGLVDMOK_L
monitors the 3.3 V regulator supply
•
V
FLLVDMOK_L
monitors the 3.3 V flash supply
•
V
IOLVDMOK_L
monitors the 3.3 V I/O supply
•
V
IOLVDM5OK_L
monitors the 5 V I/O supply
•
V
MLVDDOK_L
monitors the 1.2 V digital logic supply
LVD_MAIN is the main voltage LVD with a threshold set around 2.7 V. LVD_MAIN5 is the main voltage
LVD with a threshold set around 4 V. The LVD_MAIN and LVD_MAIN5 sense the 3.3 V–5 V power
supply for CORE, shared with IO ring supply and indicate when the 3.3 V–5 V supply is stabilized. The
threshold levels of LVD_MAIN5 are trimmable with the help of LVDM5[0:3] trim bits.