SC508 Datasheet, PDF (29/32 Pages) Semtech Corporation – EcoSpeed® DC-DC Buck Controller with Integrated LDO

Applications Information (continued)
• Place the R_TON resistor near the TON pin. Route
R_TON to the TON pin and to AGND using short
traces and avoid all switching signals.
Bypass Capacitors
The device requires bypass capacitors for the following
pins.
• VDDA pin with respect to AGND. This 0.1μF
minimum capacitor must be placed and routed
close to the IC pins, on the same layer as the IC.
This capacitor also functions as bypass for the
LDO output, since the VDDA and VLDO pins are
adjacent.
• VDDP with respect to PGND. This 1μF minimum
capacitor must be placed and routed close to
the IC pins and on the same layer as the IC.
• BST pin with respect to LX. This 0.1μF minimum
capacitor must be placed near the IC, on either
side of the PCB. Use short traces for the routing
between the capacitor and the IC.
• VIN pin with respect to AGND. This 0.1μF
minimum capacitor must be placed and routed
close to the IC pins. This capacitor provides
noise filtering for the input to the internal LDO.
SC508/SC508A
29