FAN5009MPX Fairchild Semiconductor, FAN5009MPX Datasheet - Page 10

• Manufacturer Part Number: FAN5009MPX
• Description: IC DRIVER MOSFET DUAL 12V 8MLP
• Manufacturer: Fairchild Semiconductor
• Type: High Side/Low Sider

Specifications of FAN5009MPX

• Configuration: High and Low Side, Synchronous
• Input Type: Inverting and Non-Inverting
• Delay Time: 50ns
• Number Of Configurations: 1
• Number Of Outputs: 2
• High Side Voltage - Max (bootstrap): 15V
• Voltage - Supply: 6.4 V ~ 13.5 V
• Operating Temperature: 0°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-MLP
• Supply Voltage (min): 10 V
• Supply Current: 8 mA
• Maximum Power Dissipation: 715 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: 0 C
• Number Of Drivers: 2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Peak: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

FAN4855 Rev. 1.0.1
Layout and Grounding Considerations
Careful design of printed circuit board is recommended
since high frequency switching and high peak currents
are present in DC/DC converters applications. A general
rule is to place the converter circuitry well away from any
sensitive analog components. The printed circuit board
layout should be based on some simple rules to minimize
EMI and to ensure good regulation performances:
1.
2.
3.
4.
5.
6.
Place the IC, inductor, input and output capacitor as
close together as possible.
Keep the output capacitor as close to the FAN4855
as possible with very short traces to V
pins. Typically it should be within 0.25 inches or 6
mm.
Keep the traces for the power components wide,
typically > 50 mils or 1.25 mm.
Place the external networks for LBI and FB close to
FAN4855, but away from the power components as
far as possible to prevent voltage transient from cou-
pling into sensitive nodes.
On multilayer boards use component side copper for
grounding around the IC and connect back to a quiet
ground plane using vias. The ground planes act as
electromagnetic shields for some of the RF energy
radiated.
The connection of the GND pin of the IC (pin 8) to
the overall grounding system should be directly to
the bottom of the output filter capacitor. A star
grounding system radiating from where the power
enters the PCB, is a recommended practice.
OUT
and GND
10
Application Example
The FAN4855 can be used as a constant current source
to drive white LEDs like QTLP670C-IW. As shown in the
diagram below, the current is maintained constant over a
wide range of input voltages.
19.8
19.6
19.4
19.2
18.8
18.6
18.4
18.2
+
20
19
18
Cin
10µF
0
+
1
2
3
4
1
FAN4855
L = 10µH
+
Cout
10µF
Input Voltage (V)
2
8
7
6
5
3
D1
D2
D3
D4
62Ω
62Ω
62Ω
62Ω
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