Datasheet

LM2621
www.ti.com SNVS033C –MAY 2004–REVISED MARCH 2005
Table 1. Suggested Manufacturers List
Inductors Capacitors Diodes
Coilcraft Sprague/ Vishay Motorola
Tel: [phone] Tel: [phone] Tel: [phone]
Fax: [phone] Fax: [phone] Fax: [phone]
Coiltronics Kemet International Rectifier (IR)
Tel: [phone] Tel: [phone] Tel: [phone]
Fax: [phone] Fax: [phone] Fax: [phone]
Pulse Engineering Nichicon General Semiconductor
Tel: [phone] Tel: [phone] Tel: [phone]
Fax: [phone] Fax: [phone] Fax: [phone]
PC BOARD LAYOUT
High switching frequencies and high peak currents make a proper layout of the PC board an important part of
design. Poor design can cause excessive EMI and ground-bounce, both of which can cause malfunction and loss
of regulation by corrupting voltage feedback signal and injecting noise into the control section.
Power components - such as the inductor, input and output filter capacitors, and output diode - should be placed
as close to the regulator IC as possible, and their traces should be kept short, direct and wide. The ground pins
of the input and output filter capacitors and the PGND and SGND pins of LM2621 should be connected using
short, direct and wide traces. The voltage feedback network (R
F1
, R
F2
, and C
F1
) should be kept very close to the
FB pin. Noisy traces, such as from the SW pin, should be kept away from the FB and V
DD
pins. The traces that
run between V
out
and the FB pin of the IC should be kept away from the inductor flux. Always provide sufficient
copper area to dissipate the heat due to power loss in the circuitry and prevent the thermal protection circuitry in
the IC from shutting the IC down.
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Product Folder Links: LM2621