STEVAL-ISA024V1 STMicroelectronics, STEVAL-ISA024V1 Datasheet - Page 18

• Manufacturer Part Number: STEVAL-ISA024V1
• Description: EVAL BOARD 20A 250KHZ L6725
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of STEVAL-ISA024V1

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 3.3V
• Current - Output: 20A
• Voltage - Input: 4.5 ~ 14V
• Regulator Topology: Buck
• Frequency - Switching: 250kHz
• Board Type: Fully Populated
• Utilized Ic / Part: L6725
• Input Voltage: 4.5 V to 14 V
• Output Voltage: 3.3 V
• Product: Power Management Modules
• Silicon Manufacturer: ST Micro
• Silicon Core Number: L6725
• Kit Application Type: Power Management - Voltage Regulator
• Rohs Compliant: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: L6725
• Other names: 497-5867

Application details
6
6.1
Figure 13. Inductor current ripple.
18/32
Application details
Inductor design
The inductance value is defined by a compromise between the transient response time, the
efficiency, the cost and the size. The inductor has to be calculated to sustain the output and the
input voltage variation to maintain the ripple current (ÄI
maximum output current. The inductance value can be calculated with the following
relationship:
Where F
Figure 13
V
Increasing the value of the inductance reduces the ripple current but, at the same time,
increases the converter response time to a load transient. If the compensation network is well
designed, during a load transient the device is able to set the duty cycle to 100% or to 0%.
When one of these conditions is reached, the response time is limited by the time required to
change the inductor current. During this time the output current is supplied by the output
capacitors. Minimizing the response time can minimize the output capacitor size.
IN
= 5V and V
8
7
6
5
4
3
2
1
0
SW
0
shows the ripple current vs. the output voltage for different values of the inductor, with
is the switching frequency, V
IN
= 12V at a switching frequency of 500KHz.
1
O UT P UT V O L T AG E (V )
L
≅
2
Vin
Fsw
−
∆ ⋅
Vout
IN
I
L
is the input voltage and V
⋅
3
Vout
Vin
(2)
L
) between 20% and 30% of the
4
Vin=5V, L=500nH
Vin=12V, L=1uH
Vin=5V, L=1.5uH
Vin=12V, L=2uH
OUT
is the output voltage.
L6725 - L6725A