PM6686 STMicroelectronics, PM6686 Datasheet - Page 41

• Manufacturer Part Number: PM6686
• Description: Dual Step-down Controller With Adjustable Voltages, Adjustable Ldo And Auxiliary Charge Pump Controller For Notebook
• Manufacturer: STMicroelectronics

PM6686
Table 17.
The power dissipation of the low-side MOSFET is given by:
Equation 17
Maximum conduction losses occur at the maximum input voltage:
Equation 18
Choose a synchronous rectifier with low R
fast variation of the phase node voltage can bring up even the low-side gate through its
gate-drain capacitance CRSS, causing cross-conduction problems. Choose a low-side
MOSFETs that minimizes the ratio CRSS/CGS (CGS = CISS - CRSS).
Below there is a list of some possible low-side MOSFETs.
Table 18.
Dual N-channel MOSFETs can be used in applications with a maximum output current of
about 3 A. Below there is a list of some MOSFETs manufacturers.
Table 19.
Manufacturer
Manufacturer
Manufacturer
ST
ST
ST
ST
ST
ST
High-side MOSFET manufacturer
Low-side MOSFET manufacturer
Dual MOSFET manufacturer
STS12NH3LL
STS17NH3LL
Type
STS8DNH3LL
STS4DNF60L
STS25NH3LL
STS17NF3LL
P
conduction
Type
Type
Doc ID 15281 Rev 4
Gate charge (nC)
=
R
P
DSon
DLowSide
R
R
10
18
×
DS(on)
DS(on)
DS(on)
⎛
⎜
⎜
⎝
1
5.5
3.5
25
65
−
=
P
V
(mΩ)
(mΩ)
V
. When high-side MOSFET turns on, the
conduction
IN
OUT
max
R
DS(on)
⎞
⎟
⎟
⎠
Gate charge
×
I
0.047
0.011
LOAD
C
C
8
4
(nC)
RSS
10
32
GS
(mΩ)
(max)
Application information
Rated reverse voltage (V)
2
Rated reverse voltage
Rated reverse voltage
(V)
30
30
30
30
(V)
30
60
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