LM2679-5.0EVAL National Semiconductor, LM2679-5.0EVAL Datasheet - Page 7

• Manufacturer Part Number: LM2679-5.0EVAL
• Description: EVALUATION BOARD FOR LM2679-5.0
• Manufacturer: National Semiconductor
• Series: SIMPLE SWITCHER®r

Specifications of LM2679-5.0EVAL

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 5V
• Current - Output: 5A
• Voltage - Input: 14 ~ 28V
• Regulator Topology: Buck
• Frequency - Switching: 260kHz
• Board Type: Fully Populated
• Utilized Ic / Part: LM2679
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Other names: *LM2679-5.0EVAL; LM2679-5.0-EVAL; LM2679-5.0-EVAL

Example 2: 5V/5A Design with
Surface Mount Components
For this example, it is desired to design a power supply to
convert an input voltage within the range of 14V and 28V to
an output voltage of 5V with a maximum load current of 5A
using only surface mount components. In addition, the current
limit of the regulator will be set to approximately 7.0A, and the
softstart time will be set to approximately 1.0 ms to limit the
startup surge current.
Figure 10
solution is available as evaluation board LM2679S-5_EVAL.
Figure
show the output waveforms for output voltage with 500 mA
load, output voltage with 2.5A load, output ripple with 2.5A
11,
below shows the circuit for the 5V/5A design. This
Figure
TABLE 4. Component Values for an 14V-28V in, 5V/5A Out LM2679S-5.0 Buck Converter
Component
12,
COUTX
COUT
CINX
CSS
CIN
R3*
U1
CB
D1
L1
Figure
13,
Figure
8A/35V Schottky (500 mV at 5A)
4.7 nF/100V (1.0 ms softstart)
4.99 kΩ (7.19A current limit)
14, and
2 x 180 µF/16V
3 x 15 µF/50V
FIGURE 10. 5V/5A Design Circuit
0.01µF/50V
0.47 µF
0.47µF
Value
15 µH
Figure 15
7
load, output voltage with 5A load, output ripple with 5A load,
output response to 500 mA transient load, output response to
2.5A transient load and output response to 5A transient load
respectively.
Vishay VJ1206Y47ZJXBAB
Vishay 594D156X0050R2T
Vishay 594D187X0016R2T
Vishay VJ1210U474ZXAA
Vishay VJ1210U474ZXAA
Vishay VJ1206Y103ZXXA
Suggested Part Number
Vishay CRCW12064991J
Coilcraft D05022P-153
National LM2679S-5.0
Target Design Specifications:
V
V
Motorola MBRD835L
IN
IN
V
I
LOAD
T
I
max.
OUT
CL
min.
SS
1.0 ms (approx.)
7.0A (approx.)
14V
28V
5V
5A
10114523
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