TS2509 Taiwan Semiconductor Company, TS2509 Datasheet - Page 4

• Manufacturer Part Number: TS2509
• Description: 3A / 500KHz PWM Buck Converter
• Manufacturer: Taiwan Semiconductor Company

Function Descriptions
PWM Control
The TS2509 consists of DC/DC converters that employ a pulse-width modulation (PWM) system. In converters of the
TS2509, the pulse width varies in a range from 0 to 100%, according to the load current. The ripple voltage produced
by the switching can easily be removed through a filter because the switching frequency remains constant. Therefore,
these converters provide a low-ripple power over broad ranges of input voltage and load current.
Setting the Output Voltage
Application circuit item shows the basic application circuit with TS2509 adjustable output version. The external resistor
sets the output voltage according to the following equation:
(EL CAP) Resistor select for output voltage setting
Inductor Selection
For most designs, the operate with inductors of 10µH to 22µH. 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 load current 3A, ΔIL=0.4A. 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+0.2A).
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 requirement for the input capacitor of a buck regulator is
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 applications is sufficient.
(MLCC)
A 22µF MLCC or two 10uF MLCC capacitors for most applications is sufficient.
L1 Recommend Value (V
L1 Value
V
3.3V
2.5V
1.8V
1.5V
1.2V
OUT
V
5V
1V
OUT
10~15uH
1.8V
1.3K
1.5K
2.2K
2.2K
10K
R2
2K
3K
IN
10~15uH
=12V, I
2.5V
OUT
6.8K
4.7K
4.7K
2.5K
1.5K
2.5K
=3A)
R1
2K
15~22uH
3.3V
15~22uH
5V
(MLCC) Resistor select for output voltage setting
4/9
3A / 500KHz PWM Buck Converter
V
3.3V
2.5V
1.8V
1.5V
1.2V
5V
1V
OUT
7.5K
15K
22K
27K
30K
30K
56K
R2
www.DataSheet4U.com
39K
47K
47K
33K
27K
15K
13K
R1
TS2509
Version: A09