STEVAL-ISA063V1 STMicroelectronics, STEVAL-ISA063V1 Datasheet - Page 13

• Manufacturer Part Number: STEVAL-ISA063V1
• Description: BOARD EVAL BASED ON STBB1XX
• Manufacturer: STMicroelectronics

Specifications of STEVAL-ISA063V1

• Main Purpose: DC/DC, Step Up or Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.2 ~ 5.5 V
• Current - Output: 1A
• Voltage - Input: 2 ~ 5.5 V
• Regulator Topology: Buck-Boost
• Frequency - Switching: 1.5MHz
• Board Type: Fully Populated
• Utilized Ic / Part: STBB1
• Product: Power Management Modules
• Silicon Manufacturer: ST Micro
• Silicon Core Number: STBB1XX
• Kit Application Type: Power Management - Voltage Regulator
• Application Sub Type: Buck/Boost DC-DC Converter
• Kit Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-9008

STBB1XX
8
8.1
8.2
Application information
Programming the output voltage
The STBB1 is available in two versions: fixed output voltage (STBB1PURXX) and adjustable
output voltage (STBB1PUR).
In the first case the device integrates the resistor divider needed to set the correct output
voltage. This allows the saving of 2 external components. The FB pin must be connected
directly to V
For the adjustable version, the resistor divider must be connected between V
and the middle point of the divider must be connected to FB as shown in
Equation 1
A suggested value for R2 is 100 kΩ. To reduce the power consumption a maximum value of
500 kΩ can be used.
Inductor selection
The inductor is the key passive component for switching converters. With a buck-boost
device, the inductor selection must take into consideration the boundary conditions in which
the converter works, as buck at the maximum input voltage and as a boost at the minimum
input voltage.
Two critical inductance values are then obtained according to the following formulas:
Equation 2
Equation 3
where:
fs: minimum switching frequency
ΔI
can be set at 10 % - 20 % of the output current.
L
L
R
MIN
MIN
1
L
=
= the peak-to-peak inductor ripple current. As a rule of thumb, the peak-to-peak ripple
−
−
R
BOOST
BUCK
2
×
⎛
⎜ ⎜
⎝
=
V
OUT
V
=
OUT
VOUT
FB
VIN
.
−
VIN
MIN
1
VOUT
⎞
⎟ ⎟
⎠
×
(
MAX
×
VIN
(
VOUT
×
MAX
×
fs
fs
×
×
−
Doc ID 15474 Rev 5
−
Δ
Δ
VOUT
VIN
I
I
L
L
MIN
)
)
Application information
Figure
OUT
3.
and GND
13/21