The LM2738 demo board is configured to convert 12-V input to 3.3-V output at 1.5-A load current using the LM2738X 1.6-MHz or the LM2738Y 550-kHz step down DC-DC regulator. The tiny low profile MSOP-PowerPAD-8 and WSON-8 packages allows the demo board to be manufactured using just over one square inch of a 4-layer printed circuit board.

The circuit is configured with the boost diode connected to V_OUT, and according to the data sheet, V_OUT must not exceed the maximum operating limit of 5.5 V + V_fD2 using this configuration. This makes sure that the voltage between the boost and SW pins, V_BOOST–V_SW, does not exceed 5.5 V for proper operation. Please see the LM2738 550kHz/1.6MHz 1.5A Step-Down DC-DC Switching Regulator data sheet for more information regarding this requirement.

A bill of materials describes the parts used on this demo board. A schematic and layout have also been included along with measured performance characteristics. The schematics at the end of this document show how to re-configure this demo board for various input and output conditions as discussed in the LM2738 550kHz/1.6MHz 1.5A Step-Down DC-DC Switching Regulator data sheet. Short or leave open the indicated connection as indicated in the schematics. The above restrictions for the input voltage are valid only for the demo board as shipped with the demo board schematic (see Figure 2-1).

• V_IN = 12 V
• V_O = 3.3 V
• I_O = 1.5 A

Figure 2-1 LM2738 Demo Board Schematic - V_BOOST Derived from V_OUT = 3.3 V, V_IN = 12 V

Figure 2-2 Efficiency vs Load Current - V_IN = 12 V, V_OUT = 3.3 V