STEVAL-ISA052V2 STMicroelectronics, STEVAL-ISA052V2 Datasheet - Page 39

• Manufacturer Part Number: STEVAL-ISA052V2
• Description: BOARD EVAL BASED ON PM6675A
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of STEVAL-ISA052V2

• Design Resources: STEVAL-ISA052V2 Gerber Files STEVAL-ISA052V2 Schematic STEVAL-ISA052V2 Bill of Material
• Main Purpose: DC/DC, Step Down with LDO
• Outputs And Type: 2, Non-Isolated
• Voltage - Output: 1.5V, 0.6 ~ 3.3V
• Voltage - Input: 4.5 ~ 36 V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: PM6675AS
• Input Voltage: 4.5 V to 36 V
• Output Voltage: 1.5 V
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Power - Output: -
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Supplier Unconfirmed
• For Use With/related Products: PM6675AS
• Other names: 497-8413

PM6675AS
8.1.4
In
Table 13.
MOSFETs selection
In SMPS converters, power management efficiency is a high level requirement, so the
power dissipation on the power switches becomes an important factor in switches selection.
Losses of high-side and low-side MOSFETs depend on their working condition.
Considering the high-side MOSFET, the power dissipation is calculated as:
Equation 40
Maximum conduction losses are approximately given by:
Equation 41
where R
Switching losses are approximately given by:
Equation 42
where t
gate-driver current capability and the gate charge Q
low R
As general rule, the R
MOSFET.
Logic-level MOSFETs are recommended, as long as low-side and high-side gate drivers are
powered by VVCC = +5 V. The breakdown voltage of the MOSFETs (VBRDSS) must be
greater than the maximum input voltage V
Below some tested high-side MOSFETs are listed.
Table 13
Manufacturer
HITACHI
SANYO
DSon
ON
P
DSon
switching
. Unfortunately low R
and t
some tested polymer capacitors are listed.
Evaluated output capacitors
is the MOSFET drain-source on-resistance.
OFF
=
V
TNCB OE227MTRYF
are the turn-on and turn-off times of the MOSFET and depend on the
IN
DSon
⋅
I (
4TPE220MF
4TPE150MI
4TPC220M
LOAD
Series
.
P
Q
conduction
(max)
gate
P
DSon
DHighSide
2
product should be minimized to find out the suitable
−
MOSFETs have a great gate charge.
=
∆
2
I
R
L
=
)
DSon
⋅
P
INmax
Capacitance
t
conduction
on
⋅
⋅
(µF)
220
150
220
220
V
f
V
.
sw
IN
OUT
.
min
+
gate
+
V
P
⋅
IN
I
. A greater efficiency is achieved with
switching
LOAD
⋅
I (
Rated voltage
LOAD
,
MAX
2.5 V
4 V
4 V
4 V
(V)
(max)
2
Application information
2
+
∆
2
I
L
)
@100kHz (mΩ)
⋅
t
off
ESR max
15 to 25
⋅
f
18
40
25
sw
39/48