sp7600 Exar Corporation, sp7600 Datasheet - Page 11

• Manufacturer Part Number: sp7600
• Description: 2amp, 29v Buck Converter For Led Driver Applications
• Manufacturer: Exar Corporation

Layout Suggestions
i) Place the bypass capacitors C4 and C5 as close as possible to the 7600 IC. See figure 5 for
details.
ii) Create a pad under the IC that connects the power pad (pin 9) to the inductor. Duplicate this pad
through the pcb layers if present, and on the bottom side of the PCB. Use multiple vias to connect
these layers to aid in heat dissipation. Do not oversize this pad - since the LX node is subjected to
very high dv/dt voltages, the stray capacitance formed between these islands and the surrounding
circuitry will tend to couple switching noise
iii) Connect the Schottky diode cathode as close as possible to the LX node and inductor input side.
Connect the anode to a large diameter trace or a copper area that connects the input ground to the
output ground.
iv) The output capacitor, if used, should be placed close to the load. Use short wide copper regions
to connect output capacitors to load to minimize inductance and resistances.
v) Keep other sensitive circuits and traces away from the LX node in particular and away from the
power supply completely if possible.
For more detail on the SP7600 layout see the SP7600EB Evaluation Board Manual available on our
web site. Each layer is shown in detail as well as a complete bill of materials.
12/17/07 rev: A
EXAR RESERVES THE RIGHT TO MAKE CHANGES TO THIS DATASHEET. CALL FOR UPDATES: 1-510-668-7000
Figure 5. SP7600 component side layout with critical power components labeled
CIN
7600
DIODE
L1
COUT
SP7600
11
©Copyright 2007 Exar Corporation
SP7600