STEVAL-ISA043V2 STMicroelectronics, STEVAL-ISA043V2 Datasheet - Page 9

• Manufacturer Part Number: STEVAL-ISA043V2
• Description: BOARD EVAL BASED ON ST1S06
• Manufacturer: STMicroelectronics

Specifications of STEVAL-ISA043V2

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 3.3V
• Current - Output: 1.5A
• Voltage - Input: 2.7 ~ 6V
• Regulator Topology: Buck
• Frequency - Switching: 1.5MHz
• Board Type: Fully Populated
• Utilized Ic / Part: ST1S06
• Product: Power Management Modules
• Silicon Manufacturer: ST Micro
• Silicon Core Number: ST1S06PUR
• Kit Application Type: Power Management - Voltage Regulator
• Application Sub Type: Synchronous Buck Converter
• Kit Contents: Board
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-6420; STEVAL-ISA043V2

AN2371
4.1
4.2
External component selection
Figure 5
Figure 5.
In order to obtain the needed output voltage, we must choose the resistor divider according
to the following formula:
Equation 16
with
The resistor divider used in
consumption and minimum output voltage. For output voltages close to the feedback
voltage, we suggest adding a very small capacitor in parallel with R
As an alternative, we suggest increasing the current in the resistor divider while decreasing
the R
Inductor selection
Due to the high (1.5 MHz) frequency it is possible to use very small inductor values. In our
board, we tested the device with an inductor in the 1 µH to 10 µH range with very good
efficiency performance (see below).
As the device can provide an operative output current of 1.5 A, we strongly recommend
using inductors able to manage at least 2.5 A.
1
and R
shows the typical application used to obtain an output voltage of 1.2 V.
Vin
ST1S06 application schematic
2
values.
4.7µF
C1
4
5
6
VIN_A
VIN_SW
INH
GND
2
Figure 5
ST1S06
V
OUT
represents a good compromise in terms of current
50K
R2
V
=
FB
VFB
1
V
FB
=
SW
0.8 V
⋅
3
25K
R1
1
+
R
------ -
R
1
2
3.3µH
Board usage recommendation
L1
1
Vout=1.2V
in the range of 10 pF.
22µF
C2
9/12