TPS40200-Q1
SLUS739D –SEPTEMBER 2006–REVISED JULY 2011
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EXAMPLE APPLICATIONS
Application 1: Buck Regulator, 8-V to 12-V Input, 3.3-V or 5-V Output at 2.5 A
Overview
The buck regulator design shown in Figure 35 shows the use of the TPS40200. It delivers 2.5 A at either 3.3 V or
5 V as selected by a single feedback resistor. It achieves approximately 90% efficiency at 3.3 V and 94% at 5 V.
A discussion of design tradeoffs and methodology is included to serve as a guide to the successful design of
forward converters using the TPS40200.
The bill of materials for this application is given in Table 3. The efficiency from boards built from this design is
shown in Figure 36 and Figure 37. Gerber files and additional application information are available.
+
+
Notes
D3 : Do not populate. SOT 23 Common Cathode Dual Schottky
R6 =26.7k for 3.3 Vout, R6 = 16.2k for 5.0 Vout
Figure 35. 8-V to 16-V VIN Step-Down Buck Converter
100
100
VIN = 8 V
VIN = 12 V
90
VIN = 16 V
90
VIN = 8 V
VIN = 12 V
VIN = 16 V
80
80
70
70
60
60
VOUT = 5 V
VOUT = 3.3 V
50
50
0
0.5
1
1.5
2
2.5
3
0
0.5
1
1.5
2
2.5
3
Load Current - A
Load Current - A
Figure 36. Full-Load Efficiency at 5-V VOUT
Figure 37. Full-Load Efficiency at 3.3-V VOUT
18
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