PC7410 datasheet(41/54 Pages) ATMEL

41 / 54 page

PC7410

2141D–HIREL–02/04

It is the recommendation of Motorola, that systems that implement the AV

DD filter shown

in Figure 29 design in the pads for the removed capacitors (shown in Figure 28), to pro-

vide for the possible reintroduction of the filter in Figure 28. This would be necessary in

case there is a planned transition to the HCTE package of the PC7410.

Figure 28. PLL Power Supply Filter Circuit #1

Figure 29. PLL Power Supply Filter Circuit #2

Power Supply Voltage

Sequency

The notes in Table 2 contain cautions about the sequencing of the external bus voltages

and core voltage of the PC7410 (when they are different). These cautions are necessary

for the long term reliability of the part. If they are violated, the electrostatic discharge

(ESD) protection diodes will be forward-biased and excessive current can flow through

these diodes. If the system power supply design does not control the voltage sequenc-

ing, one or both of the circuits of Figure 30 can be added to meet these requirements.

The MUR420 Schottky diodes of Figure 30 control the maximum potential difference

between the external bus and core power supplies on power-up and the 1N5820 diodes

regulate the maximum potential difference on power-down.

Figure 30. Example Voltage Sequencing Circuits

VDD

Ω

2.2

µF

2.2

µF

GND

AVDD (or L2AVDD)

Low ESL surface mount capacitor

VDD

AVDD

Ω

GND

Capacitor

Pad Sites

MUR420

1N5820

1.8V

2.5V

PC7410 Datasheet(PDF) 41 Page - ATMEL Corporation