7.4 Thermal Information
THERMAL METRIC(1) |
LMK04228 |
UNIT |
NKD (WQFN) |
64 PINS |
RθJA |
Junction-to-ambient thermal resistance(2) |
24.3 |
°C/W |
RθJC(top) |
Junction-to-case (top) thermal resistance(3) |
6.1 |
°C/W |
RθJB |
Junction-to-board thermal resistance(4) |
3.5 |
°C/W |
ψJT |
Junction-to-top characterization parameter(5) |
0.1 |
°C/W |
ψJB |
Junction-to-board characterization parameter(6) |
3.5 |
°C/W |
RθJC(bot) |
Junction-to-case (bottom) thermal resistance(7) |
0.7 |
°C/W |
(2) The junction-to-ambient thermal resistance under natural convection is obtained in a simulation on a JEDEC-standard, High-K board, as specified in JESD51-7, in an environment described in JESD51-2a.
(3) The junction-to-case(top) thermal resistance is obtained by simulating a cold plate test on the package top. No specific JEDEC-standard test exists, but a close description can be found in the ANSI SEMI standard G30-88.
(4) The junction-to-board thermal resistance is obtained by simulating in an environment with a ring cold plate fixture to control the PCB temperature, as described in JESD51-8.
(5) The junction-to-top characterization parameter, ΨJT, estimates the junction temperature of a device in a real system and is extracted from the simulation data for obtaining RθJA, using a procedure described in JESD51-2a (sections 6 and 7).
(6) The junction-to-board characterization parameter, ΨJB estimates the junction temperature of a device in a real system and is extracted from the simulation data for obtaining RθJA , using a procedure described in JESD51-2a (sections 6 and 7).
(7) The junction-to-case(bottom) thermal resistance is obtained by simulating a cold plate test on the exposed (power) pad. No specific JEDEC standard test exists, but a close description can be found in the ANSI SEMI standard G30-88.