PXD10 datasheet(73/130 Pages) FREESCALE

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Electrical characteristics

PXD10 Microcontroller Data Sheet, Rev. 1

Freescale Semiconductor

3.7.4

Recommended power-up and power-down order

Figure 6 shows the recommended order for powering up the power supplies on this device.

The 1.2 V regulator output starts after the device’s internal POR (VDDREG HV) is deasserted at

approximately 2.7 V on VDDREG.

Figure 6. Recommended order for powering up the power supplies

CAUTION

The voltages VA and VB in Figure 6 must always obey the relation

VB  VA – 0.7 V. Otherwise, currents from the 1.2 V supply to the 3.3 V

supply may result.

Figure 7 shows the recommended order for powering down the power supplies on this device.

It is acceptable for the VDD IO HV supply to ramp down faster than the 1.2 V regulator output, even if

the latter takes time to discharge the high 40

F capacitance. (The capacitor will ultimately discharge.)

2 Values provided for reference only. The permitted temperature range of the chip is specified separately.

VDDREG HV supply

VDDREG HV POR (internal)

1.2 V regulator output

Soft startup (approx. 200

s)

VDD IO HV supply (3–5.5 V)

 2.7 V

>= 200

s

PXD10 Datasheet(PDF) 73 Page - Freescale Semiconductor, Inc