MPC5674F datasheet(30/132 Pages) FREESCALE

30 / 132 page

MPC5674F Microcontroller Data Sheet, Rev. 6

Electrical Characteristics

Freescale Semiconductor

4.6.1

Power-Up

If VDDE/VDDEH is powered up first, then a threshold detector tristates all drivers connected to VDDE/VDDEH. There is no limit

to how long after VDDE/VDDEH powers up before VDD must power up. If there are multiple VDDE/VDDEH supplies, they can

be powered up in any order. For each VDDE/VDDEH supply not powered up, the drivers in that VDDE/VDDEH segment exhibit

the characteristics described in the next paragraph.

If VDD is powered up first, then all pads are loaded through the drain diodes to VDDE/VDDEH. This presents a heavy load that

pulls the pad down to a diode above VSS. Current injected by external devices connected to the pads must meet the current

injection specification. There is no limit to how long after VDD powers up before VDDE/VDDEH must power up.

The rise times on the power supplies are to be no faster than 25 V/millisecond.

4.6.2

Power-Down

If VDD is powered down first, then all drivers are tristated. There is no limit to how long after VDD powers down before

VDDE/VDDEH must power down.

If VDDE/VDDEH is powered down first, then all pads are loaded through the drain diodes to VDDE/VDDEH. This presents a heavy

load that pulls the pad down to a diode above VSS. Current injected by external devices connected to the pads must meet the

current injection specification. There is no limit to how long after VDDE/VDDEH powers down before VDD must power down.

There are no limits on the fall times for the power supplies.

4.6.3

Power Sequencing and POR Dependent on VDDA

During power up or down, VDDA can lag other supplies (of magnitude greater than VDDEH/2) within 1 V to prevent any

forward-biasing of device diodes that causes leakage current and/or POR. If the voltage difference between VDDA and VDDEH

is more than 1 V, the following will result:

•

Triggers POR (ADC monitors on VDDEH1 segment which powers the RESET pin) if the leakage current path created,

when VDDA is sufficiently low, causes sufficient voltage drop on VDDEH1 node monitored crosses low-voltage detect

level.

•If VDDA is between 0–2 V, powering all the other segments (especially VDDEH1) will not be sufficient to get the part

out of reset.

•

Each VDDEH will have a leakage current to VDDA of a magnitude of ((VDDEH –VDDA – 1 V(diode drop)/200 KOhms)

up to (VDDEH/2 = VDDA +1V).

Table 13. Power Sequence Pin States for F and FS pads

VDD

VDD33

VDDE

F and FS pads

low

high

Outputs drive high

low

high

—

Outputs Disabled

high

low

Outputs Disabled

high

low

high

Outputs drive high

high

low

Normal operation - except no drive current

and input buffer output is unknown.1

1 The pad pre-drive circuitry will function normally but since VDDE is unpowered

the outputs will not drive high even though the output pmos can be enabled.

high

Normal Operation

MPC5674F датащи(PDF) 30 Page - Freescale Semiconductor, Inc

MPC5674F датащи(HTML) 30 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL