Voltage Regulators and Power Supplies
MPC5606S Microcontroller Reference Manual, Rev. 7
Freescale Semiconductor 1227
Chapter 40
Voltage Regulators and Power Supplies
40.1 Introduction
This device includes three on-chip voltage regulators for power management and distribution, allowing
low-power operation and optimization of power consumption.
On this device, the general purpose inputs and outputs (GPIO) are arranged in several banks with separate
external GPIO power supply pins, allowing groups of GPIO to operate at different supply voltages.
40.2 Voltage regulators
The internal voltage regulators are used to provide a 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 is 1.2 V ± 10%. The
voltage regulator used in this device comprises three regulators.
• High power or main regulator (HPREG) requiring an external NPN ballast transistor.
• Low-power regulator (LPREG)
• Ultra low-power regulator (ULPREG)
The HPREG and LPREG regulators are switched off in Standby mode to save power consumption by the
regulator itself. During Stop and Halt modes only, the HPREG regulator may be switched off. The
ULPREG regulator is always kept ON.
The internal voltage regulators require an external capacitance to be connected to the 1.2 V supply pins in
order to provide a stable low voltage digital supply to the device. Capacitances should be placed on the
board as near as possible to the associated pins.
The regulator has two digital domains, one for the main regulator (HPREG) and the low-power regulator
(LPREG) called the “High Power domain”, and one for the ultra low-power regulator (ULPREG) called
the “Standby domain”. For each domain there is a low voltage detector (LVD) for the 1.2 V output voltage
(ULVDD and MLVDD). Additionally, there are two low voltage detectors for the main/input supply with
different thresholds, one at 3.3 V (ULVDM), the other at 5 V (ULVDM5).
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