6 Thermal Information

THERMAL METRIC ⁽¹⁾		CD74HCx4067				UNIT
		E (PDIP)	M (SOIC)	SM (SSOP)	PW (TSSOP)
		24 PINS	24 PINS	24 PINS	24 PINS
R_θJA	Junction-to-ambient thermal resistance	67	84.8	96.2	97.4	°C/W
R_θJC(top)	Junction-to-case (top) thermal resistance	N/A	57.0	60.0	45.0	°C/W
R_θJB	Junction-to-board thermal resistance	N/A	59.5	65.1	62.7	°C/W
Ψ_JT	Junction-to-top characterization parameter	N/A	29.0	21.1	5.20	°C/W
Ψ_JB	Junction-to-board characterization parameter	N/A	59.0	64.4	62.1	°C/W

(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.