MPC5645S datasheet(59/146 Pages) FREESCALE

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Qorivva MPC5645S Microcontroller Data Sheet, Rev. 8

Freescale Semiconductor

System design information

3.1

Power-up sequencing

The preferred power-up sequence for MPC5645S is as follows:

Generic IO supplies or noise-free supplies, consisting of:

— VDDA

— VDDE_A

— VDDE_B

— VDDM

— VDD_DR

— VDD33_DR

— VDDPLL

All 3.3V supplies (VDDE_B & VDD33_DR) should be ramped up first, and then the rest of the I/O supplies should

be ramped up (VDDA, VDDE_A, VDDM, VDD_DR).

VDDR, the regulator input supply, should be the last supply to ramp up; all supplies can be ramped up together as long

as VDDR is included. So all 5V supplies should be ramped up after the 3.3V supplies, and if all the supplies are of the

same level, they can be ramped up together as well.

LV supply (VDD12). If VREG is in bypass mode and the core supply (1.2V) is supplied externally, then this should

be the last supply given.

NOTE

For DDR, the 3.3 V supply (VDD33_DR) should come before VDD_DR.

This sequence ensures that when VREG releases its LVDs, the IO and other HV segments are powered properly. This is

important because MPC5645S doesn't monitor LVDs on IO HV supplies.

Electrical characteristics

4.1

Introduction

This section contains electrical characteristics of the device as well as temperature and power considerations.

This product contains devices to protect the inputs against damage due to high static voltages. However, it is advisable to take

precautions to avoid application of any voltage higher than the specified maximum rated voltages.

To enhance reliability, unused inputs can be driven to an appropriate logic voltage level (VDD or VSS). This could be done by

internal pull up and pull down, which is provided by the product for most general purpose pins.

The parameters listed in the following tables represent the characteristics of the device and its demands on the system.

In the tables where the device logic provides signals with their respective timing characteristics, the symbol “CC” for Controller

Characteristics is included in the Symbol column.

In the tables where the external system must provide signals with their respective timing characteristics to the device, the symbol

“SR” for System Requirement is included in the Symbol column.

MPC5645S датащи(PDF) 59 Page - Freescale Semiconductor, Inc