STODD01 STMicroelectronics, STODD01 Datasheet - Page 22

• Manufacturer Part Number: STODD01
• Description: Monolithic power management for high definition ODD with true shut-down, reset, and programmable step-up voltage
• Manufacturer: STMicroelectronics

Specifications of STODD01

• Typical Efficiency: > 90 %
• Low Switching Quiescent Current: max 2.2 mA overtemperature range

Application information
9.4
22/31
The critical inductance values can then be obtained according to the following formulas:
for the step-down
Equation 3
and for the step-up
Equation 4
where:
F
ΔI
can be set at 20 % - 40 % of the output current for the step-down and can be set at 20 % -
40 % of the input current for the step-up.
The peak current of the inductor can be calculated as:
Equation 5
Equation 6
In addition to the inductance value, in order to avoid saturation, the maximum saturation
current of the inductor must be higher than that of the I
Input and output capacitor selection
It is recommended to use ceramic capacitors with X5R or X7R dielectric and low ESR as
input and output capacitors, in order to filter any disturbance present in the input line and to
obtain stable operation. The output capacitor is very important for satisfying the output
voltage ripple requirement.
The output voltage ripple (V
can be calculated:
L
I
L
I
PEAK
PEAK
SW
MIN
MIN
L
= the peak-to-peak inductor ripple current. As a rule of thumb, the peak-to-peak ripple
: switching frequency
−
−
STEP
STEP
=
=
V
V
_
IN
_
OUT
DOWN
UP
_
V
MIN
IN
V
=
×
OUT
_
V
=
η
(
MAX
OUT
×
I (
×
V
OUT
(
V
IN
×
V
IN
×
OUT
_
F
×
_
/
I
OUT
MAX
SW
. 0
MIN
F
) 8
SW
−
OUT_RIPPLE
×
+
+
V
Δ
V
V
Doc ID 17789 Rev 2
−
×
IN
OUT
IN
2
I
Δ
L
V
×
_
_
I
2
OUT
MIN
MIN
V
L
×
×
IN
V (
V
_
×
)
IN
MAX
OUT
)
), in continuous mode, for the step-down channel,
(
V
_
MAX
OUT
×
×
F
F
SW
SW
−
−
V
V
×
OUT
IN
×
L
L
_
MIN
)
)
PEAK
.
STODD01