PM6680 STMicroelectronics, PM6680 Datasheet - Page 36

• Manufacturer Part Number: PM6680
• Description: IC CTRLR DUAL STEP DOWN 32VFQFPN
• Manufacturer: STMicroelectronics

Specifications of PM6680

• Applications: Controller, Notebook Power System
• Voltage - Input: 6 ~ 28 V
• Number Of Outputs: 2
• Voltage - Output: 0.9 ~ 5.5 V
• Operating Temperature: 0°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-VFQFN, 32-VFQFPN
• Output Voltage: 5 V, 0.9 V to 5.5 V, 0.9 V to 3.3 V
• Output Current: 0.33 A
• Input Voltage: 5.5 V to 28 V
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 10 C
• For Use With: 497-6379 - BOARD EVALUATION FOR PM6680A497-6378 - BOARD EVALUATION FOR PM6680497-6425 - BOARD EVAL BASED ON PM6680A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Device description
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Equation 22
Choose a synchronous rectifier with low R
variation of the phase node voltage can bring up even the low side gate through its gate-
drain capacitance C
that minimizes the ratio C
Below there is a list of some possible low side MOSFETs.
Table 14.
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 MOSFET manufacturers.
Table 15.
A rectifier across the low side MOSFET is recommended. The rectifier works as a voltage
clamp across the synchronous rectifier and reduces the negative inductor swing during the
dead time between turning the high-side MOSFET off and the synchronous rectifier on. It
can increase the efficiency of the switching section, since it reduces the low side switch
losses. A shottky diode is suitable for its low forward voltage drop (0.3 V). The diode reverse
voltage must be greater than the maximum input voltage V
reverse charge is preferable. Below there is a list of some shottky diode manufacturers.
Table 16.
Manufacturer
Manufacturer
Manufacturer
ST
ST
ST
ST
ST
ST
Low side MOSFET manufacturer
Dual MOSFET manufacturer
Shottky diode manufacturer
RSS
STS8DNH3LL
STS4DNF60L
STS25NH3LL
STS17NF3LL
P
STPS1L30M
STPS1L20M
, causing cross-conduction problems. Choose a low side MOSFET
conduction
RSS
Series
Type
Type
/C
GS
=
(C
R
DSon
GS
RDSon (mΩ)
R
voltage (V)
= C
×
Forward
DSon
DSon
⎛
⎜
⎜
⎝
0.34
0.37
1
ISS
5.5
3.5
25
65
−
(mΩ)
. When high side MOSFET turns on, the fast
V
- C
V
IN
OUT
max
RSS
⎞
⎟
⎟
⎠
Gate charge (nC)
).
×
Rated reverse
0.047
I
0.011
LOAD
C
voltage (V)
C
RSS
INmax
GS
10
32
30
20
(max)
. A minimum recovery
Rated reverse voltage (V)
2
Reverse current
Rated reverse
voltage (V)
30
30
0.000075
0.00039
(uA)
30
60
PM6680