PIC16F631/677/685/687/689/690
17.5 Thermal Considerations
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +125°C
Param
Sym
No.
Characteristic
Typ
Units
Conditions
20-pin PDIP package
TH01
θJA
Thermal Resistance
Junction to Ambient
62.4
85.2
108.1
40
C/W
C/W
C/W
C/W
C/W
C/W
C/W
C/W
C
20-pin SOIC package
20-pin SSOP package
20-pin QFN 4x4mm package
20-pin PDIP package
TH02
θJC
Thermal Resistance
Junction to Case
28.1
24.2
32.2
2.5
20-pin SOIC package
20-pin SSOP package
20-pin QFN 4x4mm package
For derated power calculations
PD = PINTERNAL + PI/O
TH03
TH04
TH05
TDIE
PD
Die Temperature
Power Dissipation
150
—
W
PINTERNAL Internal Power Dissipation
—
W
PINTERNAL = IDD x VDD
(NOTE 1)
TH06
TH07
PI/O
I/O Power Dissipation
Derated Power
—
—
W
W
PI/O = Σ (IOL * VOL) + Σ (IOH * (VDD - VOH))
PDER = PDMAX (TDIE - TA)/θJA
(NOTE 2, 3)
PDER
Note 1: IDD is current to run the chip alone without driving any load on the output pins.
2: TA = Ambient Temperature.
3: Maximum allowable power dissipation is the lower value of either the absolute maximum total power
dissipation or derated power.
DS41262D-page 236
© 2007 Microchip Technology Inc.
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