TS2507

0.5A / 330KHz PWM Buck Controller

5/9

Version: A07

Function Descriptions (Continue)

Inductor Selection

For most designs, Low inductance values are physically smaller but require faster switching, which results in some

efficiency loss. The inductor value can be derived from the following equation:

Where is inductor Ripple Current. Large value inductors lower ripple current and small value inductors result in high

ripple currents. Choose inductor ripple current approximately 15% of the maximum input current 3A, ∆IL=0.45A.

Table 2 Inductor select for output voltage setting (TS2507 at VCC=12V)

VOUT

2.5V

3.3V

5V

3.3V(5A)

5V(5A)

L1 Value

15uH

18uH

22uH

12uH

15uH

The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current

to prevent core saturation (3A+0.3A).

Layout Guidance

When laying out the PC board, the following suggestions should be taken to ensure proper operation of the TS2507.

These items are also illustrated graphically in below.

1. The power traces, including the PMOS Drain & Source trace, the Schottky and the C2 trace should be kept short,

direct and wide to allow large current flow.

2. Connect the C5 to the VCC & EN pins of the TS2507 as closely as possible to get good power filter effect.

3. Keep the switching node, away from the sensitive FB node.

4. Connect ground side of the C2 & D1 as closely as possible.

5. Connect PMOS Source and R3 as closely as possible.

6. Do not trace signal line under inductor.