Datasheet LT3479 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | 3A, Full Featured DC/DC Converter with Soft-Start and Inrush Current Protection |
| Pages / Page | 20 / 10 — APPLICATIONS INFORMATION. Figure 4. Suggested Board Layout. Switching … |
| File Format / Size | PDF / 256 Kb |
| Document Language | English |
APPLICATIONS INFORMATION. Figure 4. Suggested Board Layout. Switching Frequency. Table 4. Switching Frequency
Model Line for this Datasheet
Text Version of Document
LT3479
APPLICATIONS INFORMATION
MINIMIZE THE AREA TO VOUT OF THIS TRACE D COUT L1 CC SW GND C SW GND SS RC TO VS L SS V LT3479 V S C V FBN IN R1 R FBP C T TO V S IN SHDN VREF CIN RT R2 TO GND 3479 F04 TO SHDN PLACE VIAS AROUND EXPOSED PAD TO ENHANCE THERMAL PERFORMANCE
Figure 4. Suggested Board Layout Switching Frequency
IL 2A/DIV The switching frequency of the LT3479 is set by an exter- nal resistor attached to the RT pin. Do not leave this pin open. A resistor must always be connected for proper operation. See Table 4 and Figure 7 for resistor values VOUT and corresponding frequencies. 5V/DIV
Table 4. Switching Frequency
0.2MS/DIV 3479 F05
SWITCHING FREQUENCY (MHz) RT (kΩ) Figure 5. Start-Up with No Soft-Start Capacitor
3.5 1.78 3 2.87 IL 2.5 4.32 2A/DIV 2 6.49 1.5 10.2 1 17.8 VOUT 5V/DIV 0.5 39.2 0.2 113 0.2ms/DIV 3479 F06
Figure 6. Start-Up with CSS = 22nF
3479fc 10
APPLICATIONS INFORMATION
MINIMIZE THE AREA TO VOUT OF THIS TRACE D COUT L1 CC SW GND C SW GND SS RC TO VS L SS V LT3479 V S C V FBN IN R1 R FBP C T TO V S IN SHDN VREF CIN RT R2 TO GND 3479 F04 TO SHDN PLACE VIAS AROUND EXPOSED PAD TO ENHANCE THERMAL PERFORMANCE
Figure 4. Suggested Board Layout Switching Frequency
IL 2A/DIV The switching frequency of the LT3479 is set by an exter- nal resistor attached to the RT pin. Do not leave this pin open. A resistor must always be connected for proper operation. See Table 4 and Figure 7 for resistor values VOUT and corresponding frequencies. 5V/DIV
Table 4. Switching Frequency
0.2MS/DIV 3479 F05
SWITCHING FREQUENCY (MHz) RT (kΩ) Figure 5. Start-Up with No Soft-Start Capacitor
3.5 1.78 3 2.87 IL 2.5 4.32 2A/DIV 2 6.49 1.5 10.2 1 17.8 VOUT 5V/DIV 0.5 39.2 0.2 113 0.2ms/DIV 3479 F06
Figure 6. Start-Up with CSS = 22nF
3479fc 10
