LQFP176 datasheet(63/133 Pages) STMICROELECTRONICS

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SPC560B54x/6x

Electrical characteristics

132

Equation 2 PD = K / (TJ + 273 °C)

Therefore, solving equations <Cross Refs>1 and <Cross Refs>2:

Equation 3 K = PD x (TA + 273 °C) + RJA x PD

Where:

K is a constant for the particular part, which may be determined from Equation 3

by measuring PD (at equilibrium) for a known TA. Using this value of K, the values

of PD and TJ may be obtained by solving equations Equation 1 and Equation 2

iteratively for any value of TA.

4.6

I/O pad electrical characteristics

4.6.1

I/O pad types

The device provides four main I/O pad types depending on the associated alternate

functions:



Slow pads—are the most common pads, providing a good compromise between

transition time and low electromagnetic emission.



Medium pads—provide transition fast enough for the serial communication channels

with controlled current to reduce electromagnetic emission.



Fast pads—provide maximum speed. These are used for improved Nexus debugging

capability.



Input only pads—are associated with ADC channels and 32 kHz low power external

crystal oscillator providing low input leakage.

Medium and Fast pads can use slow configuration to reduce electromagnetic emission, at

the cost of reducing AC performance.

4.6.2

I/O input DC characteristics

Table 16 provides input DC electrical characteristics as described in Figure 6.

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