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DESIGN EXAMPLES
Example 1: Detailed Design of a 12-V to 5-V and 3.3-V Converter
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TPS54283 , , TPS54286
SLUS749C – JULY 2007 – REVISED OCTOBER 2007
The following example illustrates a design process and component selection for a 12-V to 5-V and 3.3-V dual
non-synchronous buck regulator using the TPS54283 converter. Design Example List of Materials and Table 4 ,
Definition of Symbols is found at the end of this section.
PARAMETER NOTES AND CONDITIONS MIN NOM MAX UNIT
INPUT CHARACTERISTICS
V
IN
Input voltage 6.9 12.0 13.2 V
I
IN
Input current V
IN
= nom, I
OUT
= max 1.6 2.0 A
No load input current V
IN
= nom, I
OUT
= 0 A 12 20 mA
OUTPUT CHARACTERISTICS
V
OUT1
Output voltage 1 V
IN
= nom, I
OUT
= nom 4.8 5.0 5.2
V
V
OUT2
Output voltage 2 V
IN
= nom, I
OUT
= nom 3.2 3.3 3.4
Line regulation V
IN
= min to max 1%
Load regulation I
OUT
= min to max 1%
V
OUT(ripple
Output voltage ripple V
IN
= nom, I
OUT
= max 50 mV
PP
)
I
OUT1
Output current 1 V
IN
= min to max 0 2.0
I
OUT2
Output current 2 V
IN
= min to max 0 2.0
Output overcurrent channel
A
I
OCP1
V
IN
= nom, V
OUT
= V
OUT1
= 5% 2.4 3 3.5
1
Output overcurrent channel
I
OCP2
V
IN
= nom, V
OUT
= V
OUT2
= 5% 2.4 3 3.5
2
Transient response Δ V
OUT
Δ I
OUT
= 1 A @ 3 A/ µ s 200 mV
from load transient
Transient response settling
1 ms
time
SYSTEM CHARACTERISTICS
f
SW
Switching frequency 250 310 370 kHz
η Full load efficiency 85%
Operating temperature
T
J
0 25 60 ° C
range
Figure 38. Design Example Schematic
Copyright © 2007, Texas Instruments Incorporated Submit Documentation Feedback 33
Product Folder Link(s): TPS54283 TPS54286