PI3420-00-LGIZ Datasheet, PDF (26/30 Pages) Vicor Corporation – 8 V to 18 Vin, 15 A Cool-Power ZVS Buck Regulator

Murata Part Number
Description
GRM188R71C105KA12D
1 µF 16 V 0603 X7R
GRM319R71H104KA01D
0.1 µF 50 V 1206 X7R
GRM31CR60J107ME39L
100 µF 6.3 V 1206 X5R
GRM31CR61A476ME15L
47 µF 10 V 1206 X5R
GRM31CR61E226KE15L
22 µF 25 V 1206 X5R
Table 6 — Capacitor manufacturer part numbers
Layout Guidelines
To achieve maximum efficiency and low noise performance
from a PI34xx-00 design, layout considerations are necessary.
Reducing trace resistance and minimizing high current loop
returns along with proper component placement will
contribute to optimal performance.
A typical buck regulator circuit is shown in Figure 41. The
potential areas of high parasitic inductance and resistance
are the circuit return paths, shown as LR below.
PI34xx-00
When Q1 is on and Q2 is off, the majority of C_IN’s current is
used to satisfy the output load and to recharge the C_OUT
capacitors. When Q1 is off and Q2 is on, the load current is
supplied by the inductor and the C_OUT capacitor as shown in
Figure 43. During this period C_IN is also being recharged by
the V_IN. Minimizing CIN loop inductance is important to
reduce peak voltage excursions when Q1 turns off. Also, the
difference in area between the C_IN loop and C_OUT loop is vital
to minimize switching and GND noise.
I _NV
C_NV
C_OUT
V
IN
C_IN
C_OUT
Figure 41 — Typical Buck Regulator
The path between the C_OUT and C_IN capacitors is of particular
importance since the AC currents are flowing through both
of them when Q1 is turned on.
Figure 42, schematically, shows the reduced trace length
between input and output capacitors. The shorter path
lessens the effects that copper trace parasitics can have on
the PI34xx-00 performance.
I _NV
C_NV
C_OUT
Figure 42 — Current flow: Q1 closed
Figure 43 — Current flow: Q2 closed
The recommended component placement, shown in Figure
44, illustrates the tight path between C_IN and C_OUT (and V_IN
and V_OUT) for the high AC return current. This optimized
layout is used on the PI34xx-00 evaluation board.
C_OUT
C_IN
V_OUT
GND
V_IN
GND
VSW
Figure 44 — Recommended component placement and metal routing
Figure 45 details the recommended receiving footprint for
PI34xx-00 10 mm x 14 mm package. All pads should have a
final copper size of 0.55 mm x 0.5 5mm, whether they are
solder-mask defined or copper defined, on a 1 mm x 1 mm
grid. All stencil openings are 0.55 mm when using
6mil stencil.
Cool-Power®
Page 26 of 30
Rev 1.3
12/2015
vicorpower.com
800 927.9474