If higher attenuation is required, QPIs can be
connected in series.
Figure 8
shows the proper
schematic for QPIs in series. Note that only one RY is
required in this configuration.
QPI Current (A)
14
12
10
8
6
4
2
0
The QPI can also be used to filter embedded or “down”
converters made up of discrete components. Where
ever possible a Shield Plane and Y-capacitor decoupling
should be included in the embedded converter design.
Follow the circuit and layout recommendations for a
brick converter shown in
Figures 7, 9 & 10.
0
10
20
30
40
50
60
70
80
90
100
PCB to QPI Interface Temperature (Deg. C)
Thermal Considerations
The current derating curve shown in
Figure 5
should be
used when the PCB temperature in close proximity of
the QPI-1 exceeds 60°C. For example, the QPI-1 will
support up to 10 A of current or 480 W from a 48 Vdc
bus at an 80°C interface temperature. Temperature
should be measured at the PCB interface to the QPI-1
on the Bus +/- pads or the QPI+/- pads. Refer to
Figures
9, 10 & 12
for PCB layout recommendation.
Figure 5 –
QPI-1 current derating curve.
PCB plane under converter
BUS+
QPI+
V
IN
+
V
OUT
+
C1
BUS
SUPPLY
CB
47µF
QPI
SHIELD
C
IN
CONVERTER
QPI-
C2
SHIELD
BUS-
V
IN
-
V
OUT
-
C3
C4
RY
Optional Connection
Figure 6 –
Recommended schematic for QPI. Values of C
IN
and C1-C4 should be the values recommended by the converter manufacturer.
If the manufacturer does not specify a value for the Y-capacitors use 4.7nF. Ry=10
Ω,
1/4 W.
Ordering Information
Part Number
QPI-1L
Description
QPI-1 Land Grid Array
Picor Corporation • www.picorpower.com
QPI-1L Data Sheet Rev. 2.0 Page 4 of 8
VICOR [ VICOR CORPORATION ]
