ADP3171 Ver la hoja de datos (PDF) - Analog Devices
Número de pieza
componentes Descripción
Fabricante
ADP3171 Datasheet PDF : 13 Pages
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ADP3171
improved current rating through the vias (if it is a current
path), and improved thermal performance—especially if the
vias extended to the opposite side of the PCB where a plane
can more readily transfer the heat to the air.
10. The output power path, though not as critical as the switching
power path, should also be routed to encompass a small area.
The output power path is formed by the current path through
the inductor, the current sensing resistor, the output
capacitors, and back to the input capacitors.
11. For best EMI containment, the ground plane should extend
fully under all the power components. These are the input
capacitors, the power MOSFETs and Schottky diode,
the inductor, the current sense resistor, any snubbing
elements that might be added to dampen ringing, and the
output capacitors.
Signal Circuitry
12. The output voltage is sensed and regulated between the GND
pin (which connects to the signal ground plane) and the
FB– pin. The output current is sensed (as a voltage) and
regulated between the CS– pin and the CS+ pin. In order
to avoid differential mode noise pickup in those sensed
signals, their loop areas should be small. Thus the FB–
trace should be routed atop the signal ground plane, and the
CS+ and CS– traces should be routed as a closely coupled
pair (CS+ should be over the signal ground plane as well).
13. The CS+ and CS– traces should be Kelvin connected to the
current sense resistor so that the additional voltage drop due
to current flow on the PCB at the current sense resistor
connections does not affect the sensed voltage. It is desirable
to have the ADP3171 close to the output capacitor bank and
not in the output power path, so that any voltage drop
between the output capacitors and the GND pin is minimized,
and voltage regulation is not compromised.
REV. 0
–11–
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