MC9S12XD256MAL Datasheet, PDF (555/1348 Pages) Freescale Semiconductor, Inc – Freescale’s Scalable Controller Area Network

Chapter 14
Voltage Regulator (S12VREG3V3V5)
14.1 Introduction
Module VREG_3V3 is a dual output voltage regulator that provides two separate 2.5V (typical) supplies
differing in the amount of current that can be sourced. The regulator input voltage range is from 3.3V up
to 5V (typical).
14.1.1 Features
Module VREG_3V3 includes these distinctive features:
• Two parallel, linear voltage regulators
— Bandgap reference
• Low-voltage detect (LVD) with low-voltage interrupt (LVI)
• Power-on reset (POR)
• Low-voltage reset (LVR)
• Autonomous periodical interrupt (API)
14.1.2 Modes of Operation
There are three modes VREG_3V3 can operate in:
1. Full performance mode (FPM) (MCU is not in stop mode)
The regulator is active, providing the nominal supply voltage of 2.5 V with full current sourcing
capability at both outputs. Features LVD (low-voltage detect), LVR (low-voltage reset), and POR
(power-on reset) are available. The API is available.
2. Reduced power mode (RPM) (MCU is in stop mode)
The purpose is to reduce power consumption of the device. The output voltage may degrade to a
lower value than in full performance mode, additionally the current sourcing capability is
substantially reduced. Only the POR is available in this mode, LVD and LVR are disabled. The API
is available.
3. Shutdown mode
Controlled by VREGEN (see device level specification for connectivity of VREGEN).
This mode is characterized by minimum power consumption. The regulator outputs are in a
high-impedance state, only the POR feature is available, LVD and LVR are disabled. The API
internal RC oscillator clock is not available.
This mode must be used to disable the chip internal regulator VREG_3V3, i.e., to bypass the
VREG_3V3 to use external supplies.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
555