LM3481EVAL National Semiconductor, LM3481EVAL Datasheet - Page 17

• Manufacturer Part Number: LM3481EVAL
• Description: BOARD EVAL FOR LM3481
• Manufacturer: National Semiconductor

Specifications of LM3481EVAL

• Main Purpose: DC/DC, Step Up
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 12V
• Current - Output: 1.5A
• Voltage - Input: 3 ~ 11V
• Regulator Topology: Boost
• Frequency - Switching: 300kHz
• Board Type: Fully Populated
• Utilized Ic / Part: LM3481
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

schematic shows the current flow during off-state. The bottom
schematic shows the currents we refer to as AC currents.
They are the most critical ones since current is changing in
very short time periods. The dotted lined traces of the bottom
schematic are the once to make as short as possible.
FIGURE 16. Current Flow In A Boost Application
20136597
17
The PGND and AGND pins have to be connected to the same
ground very close to the IC. To avoid ground loop currents
attach all the grounds of the system only at one point.
A ceramic input capacitor should be connected as close as
possible to the Vin pin and grounded close to the GND pin.
For a layout example please see Application Note 1204. For
more information about layout in switch mode power supplies
please refer to Application Note 1229.
COMPENSATION
For detailed explanation on how to select the right compen-
sation components to attach to the compensation pin for a
boost topology please see Application Note 1286. When cal-
culating the Error Amplifier DC gain, A
the LM3481.
EA
, R
OUT
= 152 kΩ for
www.national.com