TS2509

3A / 500KHz PWM Buck Converter

4/9

Version: B09

Function Descriptions

PWM Control

The TS2509 is a pulse-width modulation (PWM) system with a range from 0 to 100% according to different load

current. The ripple voltage produced by the switching can easily be removed through a filter because the switching

frequency remains constant.

Setting the Output Voltage

TS2509 is adjustable output version. With different output voltage setting, following tables are for external resistor

value setting as reference:

(EL CAP) Resistor select for output voltage setting

(MLCC) Resistor select for output voltage setting

R2

R1

R2

R1

5V

1.3K

6.8K

5V

7.5K

39K

3.3V

1.5K

4.7K

3.3V

15K

47K

2.5V

2.2K

4.7K

2.5V

22K

47K

1.8V

2K

2.5K

1.8V

27K

33K

1.5V

2.2K

2K

1.5V

30K

27K

1.2V

3K

1.5K

1.2V

30K

15K

1V

10K

2.5K

1V

56K

13K

Inductor Selection

For most designs are operates with inductors of 10µH to 22µH. The inductor value can be derived from the following

table:

1.8V

2.5V

3.3V

5V

L1 Value

10~15uH

10~15uH

15~22uH

15~22uH

Large value inductors can lower ripple current and small value inductors will gets higher ripple currents. Choose

inductor ripple current approximately 15% of the maximum load current 3A.

Input Capacitor Selection

(EL CAP)

This capacitor should be located close to the IC using short leads and the voltage rating should be approximately 1.5

times the maximum input voltage. The RMS current rating should be approximately 1⁄2 the DC load current. A low ESR

input capacitor sized for maximum RMS current must be used. A 220µF low ESR capacitor for most sufficient for

applications

(MLCC)

A 22µF MLCC or two 10uF MLCC capacitors for most sufficient for applications