QPI-8L Datasheet, PDF (7/8 Pages) Vicor Corporation – AdvencedTCA Hot-Swap Sip With Active EMI Filter

PRELIMINARY
45.000°
0.1773
0.0625
0.0820
14 places
0.1250
0.0820
R0.0410
0.0820
0.0200
0.492
0.441
0.400
0.300
0.100
0.000
0.100
0.300
0.400
0.441
0.492
0.9843
0.8000
QPI-8 SIP Package
(Bottom View)
Figure 13 – Start-up into short circuit
CH1: PWRGD, CH2: QPI- to BUS-, CH4: BUS- current
QPI-8 PCB Layout Considerations
For optimal QPI-8 filtering performance, care must be
taken when routing the signal paths of RY (see Figures 9a
and 9b) and the shield connections on the PC board. The
RY resistor must connect between the converter's shield
plane and the shield pin of the QPI-8. The connection to
the chassis or protective earth, if required, should be
taken directly from the QPI-8 shield pin as shown in
Figures 9a and 9b.
Figure 15 shows how this can be accomplished by using
the QPI-8's shield pin to bridge the connection between
RY and PE without allowing any parasitic paths that might
circumvent the QPI-8 and degrade filtering performance.
Reference can be made to the QPI-AN1 application note
for critical PCB layout recommendations regarding filter
performance, but use the QPI-8 pin/pad locations. Some
systems may require the converter’s positive or negative
input or output 'terminal' to be connected to PE
(Protective Earth) ground for safety or other
considerations.
When using the QPI in this situation this 'terminal' must
be connected to the converter shield plane created in the
PCB layout under the converter. Because the PE path may
pass excessive current under a fault condition the
resistance of this path may be limited to a low resistance
value. To meet the resistance requirement without
degrading filter performance RY can be replaced by a
4.7 µH inductor rated for the fault current condition
maintaining low power dissipation during a fault until the
protection device clears. The shield return PCB traces must
be sized to handle this current as well.
Figure 14 – LGA Pad, package height and pad location
dimensions in inches.
BUS+
UVEN
SW
PWRGD
OV
NC
0.4410
0.4410
QPI+
SHIELD
PLANE
UNDER
CONVERTER
QPI-
BUS-
RY
SHIELD
Figure 15 – Recommended PCB layout pattern.
QPI Package Outline
0.485
0.441
0.397
0.300
0.100
0.000
0.100
QPI PCB Pad Pattern
(Top View)
0.492
0.300
0.397
0.485
14 places
2 places
0.1310
0.0880
R0.0440
0.0440
0.0440
0.0655
0.0880
Figure 16 – Recommended PCB receiving footprint.
Ordering Information
Part Number
QPI-8L
Description
QPI-8, Land Grid Array Package
Picor Corporation • www.picorpower.com
QPI-8L Data Sheet Rev. 1.0 Page 7 of 8