MC9S08QE8 Datasheet, PDF (9/46 Pages) Freescale Semiconductor, Inc – 8-Bit HCS08 Central Processor Unit

Electrical Characteristics
1 _{Input must be current limited to the value specified. To determine the value of the required}
current-limiting resistor, calculate resistance values for positive (V_DD) and negative (V_SS) clamp
voltages, then use the larger of the two resistance values.
2 _{All functional non-supply pins, except for PTA5 are internally clamped to VSS and VDD.}
3 _{Power supply must maintain regulation within operating VDD range during instantaneous and}
operating maximum current conditions. If positive injection current (V_In > V_DD) is greater than
I_DD, the injection current may flow out of V_DD and could result in external power supply going
out of regulation. Ensure external V_DD load will shunt current greater than maximum injection
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).
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
it is user-determined rather than being controlled by the MCU design. To take P_I/O into account in power calculations, determine
the difference between actual pin voltage and V_SS or V_DD and multiply by the pin current for each I/O pin. Except in cases of
unusually high pin current (heavy loads), the difference between pin voltage and V_SS or V_DD will be very small.
Table 4. Thermal Characteristics
Rating
Operating temperature range
(packaged)
Maximum junction temperature
Thermal resistance
Single-layer board
32-pin LQFP
28-pin SOIC
20-pin SOIC
16-pin PDIP
16-pin TSSOP
Thermal resistance
Four-layer board
32-pin LQFP
28-pin SOIC
20-pin SOIC
16-pin PDIP
16-pin TSSOP
Symbol
T_A
T_JM
θ_JA
Value
Unit
T_L to T_H
–40 to 85
°C
95
°C
66
57
71
°C/W
64
108
47
42
θ_JA
52
°C/W
47
78
The average chip-junction temperature (T_J) in °C can be obtained from:
T_J = T_A + (P_D × θ_JA)
where:
Eqn. 1
MC9S08QE8 Series, Rev. 3
Freescale Semiconductor
Preliminary
9
Subject to Change Without Notice