STEVAL-ISA052V1 STMicroelectronics, STEVAL-ISA052V1 Datasheet - Page 41

• Manufacturer Part Number: STEVAL-ISA052V1
• Description: KIT EVAL PM6675S HE CTLR 2A REG
• Manufacturer: STMicroelectronics

Specifications of STEVAL-ISA052V1

• Main Purpose: DC/DC, Step Down with LDO
• Outputs And Type: 2, Non-Isolated
• Voltage - Output: 1.5V, 0.6 ~ 3.3V
• Current - Output: 10A, 2A
• Voltage - Input: 4.5 ~ 28 V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: PM6675
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-8426

PM6675S
8.1.2
The saturation current of the inductor should be greater than I
hard saturation core inductors. Using soft-ferrite cores is possible (but not advisable) to push
the inductor working near its saturation current.
In
Table 11.
In Pulse-Skip Mode, low inductance values produce a better efficiency versus load curve,
while higher values result in higher full-load efficiency because of the smaller current ripple.
Input capacitor selection
In a buck topology converter the current that flows through the input capacitor is pulsed and
with zero average value. The RMS input current can be calculated as follows:
Equation 34
Neglecting the second term, the equation 10 is reduced to:
Equation 35
The losses due to the input capacitor are thus maximized when the duty-cycle is 0.5:
Equation 36
The input capacitor should be selected with a RMS rated current higher than I
Tantalum capacitors are good in terms of low ESR and small size, but they occasionally can
burn out if subjected to very high current during operation. Multi-Layers-Ceramic-Capacitors
(MLCC) have usually a higher RMS current rating with smaller size and they remain the best
choice. The drawback is their quite high cost.
COILTRONICS
Manufacturer
Table 11
COILCRAFT
COILCRAFT
COILCRAFT
WURTH
some inductors suitable for notebook applications are listed.
Evaluated inductors (@fsw = 400 kHz)
P
loss
MVR1261C-112
MLC1538-102
MLC1240-901
7443552100
=
HC8-1R2
Series
ESR
I
Cin
RMS
Cin
⋅
I
=
CinRMS
I
Cin
I
RMS
LOAD
Inductance (µH)
(max)
=
2
⋅
I
0.9
1.1
1.2
LOAD
D
1
1
2
⋅
1 (
=
−
ESR
D
D
⋅
)
1 (
+
Cin
−
12
1
D
⋅
0 (
D
)
+40 °C RMS
current (A)
5 .
⋅
(
∆
13.4
12.4
16.0
⋅
L,PEAK
20
16
I
I
LOAD
L
)
2
Application information
(max))
as well as for case of
2
-30 % saturation
current (A)
CINRMS
21.0
24.5
25.4
20
20
(max).
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