5

LM2678

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SNVS029J – MARCH 2000 – REVISED JULY 2016

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(1)

For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application

report.

(2)

Junction to ambient thermal resistance (no external heat sink) for the 7-lead TO-220 package mounted vertically, with ½ inch leads in a

socket, or on a PCB with minimum copper area.

(3)

Junction to ambient thermal resistance (no external heat sink) for the 7-lead TO-220 package mounted vertically, with ½ inch leads

soldered to a PCB containing approximately 4 square inches of (1 oz.) copper area surrounding the leads.

(4)

Junction to ambient thermal resistance for the 7-lead DDPAK mounted horizontally against a PCB area of 0.136 square inches (the

same size as the DDPAK package) of 1 oz. (0.0014 in. thick) copper.

(5)

Junction to ambient thermal resistance for the 7-lead DDPAK mounted horizontally against a PCB area of 0.4896 square inches (3.6

times the area of the DDPAK package) of 1 oz. (0.0014 in. thick) copper.

(6)

Junction to ambient thermal resistance for the 7-lead DDPAK mounted horizontally against a PCB copper area of 1.0064 square inches

(7.4 times the area of the DDPAK 3 package) of 1 oz. (0.0014 in. thick) copper. Additional copper area reduces thermal resistance

further.

(7)

Junction to ambient thermal resistance for the 14-lead VSON mounted on a PCB copper area equal to the die attach paddle.

(8)

Junction to ambient thermal resistance for the 14-lead VSON mounted on a PCB copper area using 12 vias to a second layer of copper

equal to die attach paddle. Additional copper area will reduce thermal resistance further. For layout recommendations, see AN-1187

Leadless Leadfram Package (LLP).

6.4 Thermal Information

LM2678

UNIT

NDZ (TO-220)

KTW (TO-263)

NHM (VSON)

7 PINS

7 PINS

14 PINS

Junction-to-ambient thermal resistance

65

—

—

°C/W

45

—

—

—

56

—

—

35

—

—

26

—

—

—

55

—

—

29

2

2

—

°C/W

(1)

through correlation using standard Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level

(AOQL).

(2)

6.5 Electrical Characteristics – 3.3 V

PARAMETER

TEST CONDITIONS

Output voltage

100 mA

3.234

3.3

3.366

V

3.201

3.399

η

Efficiency

82%

(1)

through correlation using standard Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level

(AOQL).

(2)

6.6 Electrical Characteristics – 5 V

PARAMETER

TEST CONDITIONS

Output voltage

100 mA

4.9

5

5.1

V

4.85

5.15

η

Efficiency

84%