NQ03009VMA15NRS Datasheet, PDF (16/17 Pages) SynQor Worldwide Headquarters – 15A Non-Isolated DC/DC Converter in SIP configuration

Technical Specification
Non-Isolated
SIP Converter
3.0 - 3.6Vin 15A
High Capacitance Loads with Backdrive: When using
two or more NiQor converters with high capacitance loads
(greater than 1,000µF), special consideration must be given to
the following condition. If a back-drive source is feeding volt-
age back to a NiQor output, perhaps through some ASIC or
other load device, and the back-driving source is greater than
60% of the input voltage to the NiQor that has not been
enabled yet, an overcurrent condition may exist on startup. This
condition could prevent a proper startup when the second
NiQor is enabled. The condition is caused by the second
NiQor having to ramp the voltage to a high duty cycle with a
high capacitance load, which can trip the overcurrent shut-
down, preventing a startup. The following remedies for this sit-
uation can be applied:
1) Limit output capacitance on higher voltage outputs to
1,000µF. OR,
2) Prevent back-drive conditions that raise the off-state output
voltage to more than 60% of the input voltage.
Thermal Considerations: For vertical mount applications
at elevated temperatures that call for forced air cooling (see
thermal derating curves), the preferred airflow direction is from
pin 11 to pin 1, as indicated in the thermal images provided.
If airflow is in the opposite direction (pin 1 to pin 11) the power
devices will run hotter by about 5 ^OC (corresponding to an
additional 1 ampere of load derating at conditions where der-
ating occurs).
For horizontal mount applications (NQ0xxxxHMA parts),
where the inductor and power devices are facing down, the
preferred airflow direction is into the leading edge opposite the
pin header edge, such that air flowing under the NiQor PCB
flows out between the pins and the inductor. With this airflow
direction, and with the inductor firmly contacting the applica-
tion board, the user can apply the thermal derating curves pro-
vided herein for vertical mount with airflow from pin 11 to pin
1. Airflows in other directions across the horizontally mounted
NiQor will result in temperatures that are higher by about 5 ^OC
with pin 11 to pin 1 airflow and about 10 ^OC with pin 1 to pin
11 airflow. Also, temperature increases of up to 10 ^OC (2 Amp
lower derating) can be expected if the inductor thermal inter-
face does not make good contact to the customer's circuit
board.
Layout Suggestion: When using a fixed output NiQor con-
verter, the designer may chose to use the trim function and
would thus be required to reserve board space for a trim resis-
tor. It is suggested that even if the designer does not plan to use
the trim function, additional space should be reserved on the
board for a trim resistor. This will allow the flexibility to use the
Product # NQ03xxxVMA15
Phone [phone]
wide output voltage trim range NiQor module at a later date.
Any trim resistor should connect to the ground or output node
at one of the respective pins of the NiQor, so as to prevent the
trim level from being affected by load drops through the ground
or power planes.
OPTIONAL FEATURES
REMOTE SENSE(+) (Pin 3 - Optional): The optional
SENSE(+) input corrects for voltage drops along the conductors
that connect the converter’s output pins to the load.
Pin 3 should be connected to Vout(+) at the point on the board
where regulation is desired. A remote connection at the load
can adjust for a voltage drop only as large as that specified in
this datasheet, that is
Vout(+) – SENSE(+) < Sense Range % x Vout
Pin 3 must be connected for proper regulation of the output volt-
age. If these connections are not made, the converter will deliv-
er an output voltage that is slightly higher than its specified
value.
Note: the output over-voltage protection circuit senses the volt-
age across the output (pins 1, 2 and 4) to determine when it
should trigger, not the voltage across the converter’s sense lead
(pin 3).
CURRENT SHARE (Pin A - Optional): Additional informa-
tion on the current share feature will be provided in a future
revision of this technical specification. Please contact SynQor
engineering support for further details.
Doc.# 005-2NV3xxE Rev. E
6/24/04
Page 16