MFR4310 Reference Manual, Rev. 2
Freescale Semiconductor 217
Chapter 5
Dual Output Voltage Regulator (VREG3V3V2)
5.1 Introduction
The VREG3V3V2 is a dual output voltage regulator providing two separate 2.5 V (typical) supplies
differing in the amount of current that can be sourced. The regulator input voltage range is from 3.3 V up
to 5 V (typical).
5.1.1 Features
The block VREG3V3V2 includes these distinctive features:
• Two parallel, linear voltage regulators
— Bandgap reference
• Power-on reset (POR)
• Low-voltage reset (LVR)
5.1.2 Modes of Operation
VREG3V3V2 can operate in two modes on MFR4310:
• Full-performance mode (FPM)
The regulator is active, providing the nominal supply voltage of 2.5 V with full current sourcing
capability at both outputs. Features LVR (low-voltage reset) and POR (power-on reset) are
available.
• Shutdown mode
Controlled by V
DDR
.
This mode is characterized by minimum power consumption. The regulator outputs are in a high
impedance state; only the POR feature is available, and LVR is disabled.
This mode must be used to disable the chip internal regulator VREG3V3V2, i.e., to bypass the
VREG3V3V2 to use external supplies.
5.1.3 Block Diagram
Figure 5-1 shows the function principle of VREG3V3V2 by means of a block diagram. The regulator core
REG consists of two parallel sub-blocks, REG1 and REG2, providing two independent output voltages.
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