MC9S08JS16CFK datasheet(7/32 Pages) FREESCALE

7 / 32 page

Electrical Characteristics

MC9S08JS16 Series MCU Data Sheet, Rev. 4

Freescale Semiconductor

3.3

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 it is user-determined rather than being controlled by the MCU design. In order to take

PI/O into account in power calculations, determine the difference between actual pin voltage and VSS or

VDD 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 VSS or VDD will be very small.

The average chip-junction temperature (TJ) in °C can be obtained from:

TJ = TA + (PD × θJA)

Eqn. 1

where:

TA = Ambient temperature, °C

θJA = Package thermal resistance, junction-to-ambient, °C/W

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 (VDD) and negative (VSS) clamp

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

2 All functional non-supply pins are internally clamped to V

SS and VDD.

3 Power supply must maintain regulation within operating V

DD range during instantaneous and

operating maximum current conditions. If positive injection current (VIn > VDD) is greater than

IDD, the injection current may flow out of VDD and could result in external power supply going

out of regulation. Ensure external VDD 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.

Table 4. Thermal Characteristics

Rating

Symbol

Value

Unit

Operating temperature range (packaged)

TL to TH

-40 to 85

°C

Thermal resistance 1,2,3,4

24-pin QFN

2s2p

20-pin SOIC

2s2p

1 Junction temperature is a function of die size, on-chip power dissipation, package thermal

resistance, mounting site (board) temperature, ambient temperature, air flow, power dissipation

of other components on the board, and board thermal resistance

2 Junction to Ambient Natural Convection

3 1s — Single layer board, one signal layer

4 2s2p — Four layer board, 2 signal and 2 power layers

°C/W

MC9S08JS16CFK Datasheet(PDF) 7 Page - Freescale Semiconductor, Inc

MC9S08JS16CFK Datasheet(HTML) 7 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Datasheet Download

Link URL