36.9 Thermal Specifications

Table 36-9. Thermal Specifications
Symbol	Description	Typ.	Unit	Conditions
θ_JA	Thermal Resistance Junction to Ambient	73.7	°C/W	14-pin TSSOP package (SS)
62.1	°C/W	14-pin SOIC package (SO)
61.4	°C/W	20-pin SSOP package (SS)
68	°C/W	20-pin VQFN package (REB)
48.5	°C/W	28-pin PDIP package (SP)
44	°C/W	28-pin SOIC package (SO)
53.3	°C/W	28-pin SSOP package (SS)
33.5	°C/W	32-pin VQFN package (RXB)
53	°C/W	32-pin TQFP package (PT)
Note: Calculate power dissipation as follows: P_DIS = V_DD × {I_DD - Σ I_OH} + Σ {(V_DD - V_OH) × I_OH} + Σ (V_OI × I_OL) Calculate Internal Power Dissipation as P_INTERNAL = I_DD × V_DD, where I_DD is the current running the chip alone without driving any load on the output pins. Calculate Derated Power as follows: P_DER = PD_MAX (T_J - T_A)/θ_JA, where T_A = Ambient Temperature, T_J = Junction Temperature.

θ_JA

Thermal Resistance Junction to Ambient

73.7

°C/W

14-pin TSSOP package (SS)

62.1

°C/W

14-pin SOIC package (SO)

61.4

°C/W

20-pin SSOP package (SS)

68

°C/W

20-pin VQFN package (REB)

48.5

°C/W

28-pin PDIP package (SP)

44

°C/W

28-pin SOIC package (SO)

53.3

°C/W

28-pin SSOP package (SS)

33.5

°C/W

32-pin VQFN package (RXB)

53

°C/W

32-pin TQFP package (PT)

Note:

Calculate power dissipation as follows:
P_DIS = V_DD × {I_DD - Σ I_OH} + Σ {(V_DD - V_OH) × I_OH} + Σ (V_OI × I_OL)
Calculate Internal Power Dissipation as P_INTERNAL = I_DD × V_DD, where I_DD is the current running the chip alone without driving any load on the output pins.
Calculate Derated Power as follows: P_DER = PD_MAX (T_J - T_A)/θ_JA, where T_A = Ambient Temperature, T_J = Junction Temperature.