6.4 Thermal Information
| THERMAL METRIC(1) |
LM2585 |
UNIT |
| KTT (DDPAK/TO-263 |
NDH (TO-220) |
| 5 PINS |
5 PINS |
| RθJA |
Junction-to-ambient thermal resistance |
56(2) |
65(3) |
°C/W |
| 35(4) |
45(5) |
| 26(6) |
— |
| RθJC |
Junction-to-case thermal resistance |
2 |
2 |
°C/W |
(2) Junction-to-ambient thermal resistance for the 5-lead TO-263 mounted horizontally against a PC board area of 0.136 square inches (the same size as the DDPAK/TO-263 package) of 1 oz. (0.0014 in. thick) copper.
(3) Junction-to-ambient thermal resistance (no external heat sink) for the 5-lead TO-220 package mounted vertically, with ½ inch leads in a socket, or on a PC board with minimum copper area.
(4) Junction-to-ambient thermal resistance for the 5-lead TO-263 mounted horizontally against a PC board area of 0.4896 square inches (3.6 times the area of the DDPAK/TO-263 package) of 1 oz. (0.0014 in. thick) copper.
(5) Junction-to-ambient thermal resistance (no external heat sink) for the 5-lead TO-220 package mounted vertically, with ½ inch leads soldered to a PC board containing approximately 4 square inches of (1 oz.) copper area surrounding the leads.
(6) Junction-to-ambient thermal resistance for the 5-lead TO-263 mounted horizontally against a PC board copper area of 1.0064 square inches (7.4 times the area of the DDPAK/TO-2633 package) of 1 oz. (0.0014 in. thick) copper. Additional copper area reduces thermal resistance further.