LTC1646CGN View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LTC1646CGN Datasheet PDF : 20 Pages
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LTC1646
APPLICATIO S I FOR ATIO
PCB Layout Considerations
For proper operation of the LTC1646’s circuit breaker
function, a 4-wire Kelvin connection to the sense resistors
is highly recommended. A recommended PCB layout for
the sense resistor, the power MOSFET, and the GATE drive
components around the LTC1646 is illustrated in
Figure␣ 15. In Hot Swap applications where load currents
can reach 10A, narrow PCB tracks exhibit more resistance
than wider tracks and operate at more elevated tempera-
tures. Since the sheet resistance of 1 ounce copper foil is
approximately 0.5mΩ/s, track resistances add up quickly
in high current applications. Thus, to keep PCB track
resistance and temperature rise to a minimum, the sug-
gested trace width in these applications for 1 ounce
copper foil is 0.03" for each ampere of DC current.
In the majority of applications, it will be necessary to use
plated-through vias to make circuit connections from
component layers to power and ground layers internal to
the PC board. For 1 ounce copper foil plating, a general rule
is 1A of DC current per via, making sure the via is properly
dimensioned so that solder completely fills any void. For
other plating thicknesses, check with your PCB fabrication
facility.
Power MOSFET and Sense Resistor Selection
Table 6 lists some current MOSFET transistors that are
available and Table 7 lists some current sense resistors
that can be used with the LTC1646’s circuit breakers.
Table 8 lists supplier web site addresses for discrete
component mentioned throughout the LTC1646 data sheet.
Table 6. N-Channel Power MOSFET Selection Guide
CURRENT LEVEL (A)
PART NUMBER
DESCRIPTION
0 to 2
2 to 5
5 to 10
5 to 10
5 to 10
MMDF3N02HD
MMSF5N02HD
MTB50N06V
IRF7413
Si4410DY
Dual N-Channel SO-8
RDS(ON) = 0.1Ω
Single N-Channel SO-8
RDS(ON) = 0.025Ω
Single N-Channel DD Pak
RDS(ON) = 0.028Ω
Single N-Channel SO-8
RDS(ON) = 0.01Ω
Single N-Channel SO-8
RDS(ON) = 0.01Ω
Table 7. Sense Resistor Selection Guide
CURRENT LIMIT VALUE PART NUMBER
1A
LR120601R055F
WSL1206R055
2A
LR120601R028F
WSL1206R028
5A
LR120601R011F
WSL2010R011
7.6A
WSL2512R007
10A
WSL2512R005
DESCRIPTION
0.055Ω, 0.5W, 1% Resistor
0.028Ω, 0.5W, 1% Resistor
0.011Ω, 0.5W, 1% Resistor
0.007Ω, 1W, 1% Resistor
0.005Ω, 1W, 1% Resistor
MANUFACTURER
ON Semiconductor
ON Semiconductor
ON Semiconductor
International Rectifier
Vishay-Siliconix
MANUFACTURER
IRC-TT
Vishay-Dale
IRC-TT
Vishay-Dale
IRC-TT
Vishay-Dale
Vishay-Dale
Vishay-Dale
18
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