Electrical Characteristics

MC9S08QE8 Series, Rev. 3

Preliminary

Subject to Change Without Notice

Freescale Semiconductor

9

3.4

Thermal Characteristics

This section provides information about operating temperature range, power dissipation, and package thermal resistance. Power

dissipation on I/O pins is usually small compared to the power dissipation in on-chip logic and voltage regulator circuits, and

Eqn. 1

where:

1

Input must be current limited to the value specified. To determine the value of the required

voltages, then use the larger of the two resistance values.

current. This will be the greatest risk when the MCU is not consuming power. Examples are: if

no system clock is present, or if the clock rate is very low (which would reduce overall power

consumption).

Table 4. Thermal Characteristics

Rating

Symbol

Value

Unit

Operating temperature range

(packaged)

–40 to 85

°C

Maximum junction temperature

95

°C

Thermal resistance

Single-layer board

32-pin LQFP

θ

JA

66

°C/W

28-pin SOIC

57

20-pin SOIC

71

16-pin PDIP

64

16-pin TSSOP

108

Thermal resistance

Four-layer board

32-pin LQFP

θ

JA

47

°C/W

28-pin SOIC

42

20-pin SOIC

52

16-pin PDIP

47

16-pin TSSOP

78