LM2678-3.3 NSC [National Semiconductor], LM2678-3.3 Datasheet - Page 5

• Manufacturer Part Number: LM2678-3.3
• Description: SIMPLE SWITCHER High Efficiency 5A Step-Down Voltage Regulator
• Manufacturer: NSC [National Semiconductor]

All Output Voltage Versions
Electrical Characteristics
Note 4: All limits are guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits are 100%
tested during production with T
methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
Note 5: Junction to ambient thermal resistance (no external heat sink) for the 7 lead TO-220 package mounted vertically, with
board with minimum copper area.
Note 6: Junction to ambient thermal resistance (no external heat sink) for the 7 lead TO-220 package mounted vertically, with
containing approximately 4 square inches of (1 oz.) copper area surrounding the leads.
Note 7: Junction to ambient thermal resistance for the 7 lead TO-263 mounted horizontally against a PC board area of 0.136 square inches (the same size as the
TO-263 package) of 1 oz. (0.0014 in. thick) copper.
Note 8: Junction to ambient thermal resistance for the 7 lead TO-263 mounted horizontally against a PC board area of 0.4896 square inches (3.6 times the area
of the TO-263 package) of 1 oz. (0.0014 in. thick) copper.
Note 9: Junction to ambient thermal resistance for the 7 lead TO-263 mounted horizontally against a PC board copper area of 1.0064 square inches (7.4 times the
area of the TO-263 package) of 1 oz. (0.0014 in. thick) copper. Additional copper area will reduce thermal resistance further. See the thermal model in Switchers
Made Simple
Note 10: Junction to ambient thermal resistance for the 14-lead LLP mounted on a PC board copper area equal to the die attach paddle.
Note 11: Junction to ambient thermal resistance for the 14-lead LLP mounted on a PC board 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, refer to Application Note AN-1187.
®
software.
A
= T
J
= 25˚C. All limits at temperature extremes are guaranteed via correlation using standard standard Quality Control (SQC)
(Continued)
5
1
1
⁄
⁄
2
2
inch leads soldered to a PC board
inch leads in a socket, or on a PC
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