NQ04W33XMA16 Datasheet, PDF (12/13 Pages) SynQor Worldwide Headquarters – SIP DC/DC converter

Technical Specification
Input: 3.0 - 6.0V
Outputs: 0.75 - 3.6V
Current: 16A
Package: SIP
Specifications section of the data sheet under all conditions of
turn-on, turn-off and load transients and fault conditions. The
power source should have an over voltage shutdown threshold as
close as reasonably possible to the operating point.
Additional protection can come from additional input capaci-
tance, perhaps on the order of 1,000µF, but contingent on the
source inductance value. A large source inductance would
require more capacitance to keep the input voltage below the
absolute maximum, if the load current were interrupted suddenly.
This can be caused by either a shutdown of the NiQor from a
fault or from the load itself, for example when a card is hot-
swapped out, suddenly dropping the load to zero. This is further
justification for keeping the source inductance low, as mentioned
above. When the power source is configured with remote sens-
ing, the series resistance of the filter inductor and any other con-
ductors or devices between the source and the sense point will
result in a voltage drop which, in the event of a load current inter-
ruption, would add to the NiQor input voltage.
A TVS device could also be used to clamp the voltage level dur-
ing these conditions, but the relatively narrow range between
operating voltage and the absolute maximum voltage restrict the
use of these devices to lower source current levels that will not
drive the transient voltage suppressor above the voltage limit
when all the source current is flowing into the clamp. A TVS
would be a good supplemental control, in addition to careful
selection of inductance and capacitance values.
Equivalent Model for Input Ripple: A simple but reason-
ably accurate model of input ripple is to treat the NiQor input as
a pulsed AC current source at 300 kHz.in parallel with a very
low ESR capacitor, see Figure E. The peak-to-peak current of the
source model is equal to the NiQor load current, representing the
peak current in the NiQor's smoothing choke. The capacitor rep-
resents the 40µF input ceramic capacitance of the NiQor con-
verter, with a nearly negligible ESR of less than 1 mW. A further
refinement can be made by setting the duty cycle of the pulsed
source to the output voltage divided by the input voltage.
The only error in this simplified model is that it ignores the ripple
current in the choke, usually less than 20% of the load current,
and it ignores the resistive losses inside the NiQor converter,
which would alter the duty cycle very slightly.
The model is a good guide for calculating the effects of external
input capacitors and other filter elements on ripple voltage and
ripple current stress on capacitors.
30µF _INPUT
I_p-p
<1mW
I _p-p = I _Load
Figure E: Equivalent model for input ripple
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 resistor. 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 wide output
voltage trim range NiQor module at a later date. Any trim resis-
tor 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 voltage
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).
RoHS Compliance: The EU led RoHS (Restriction of Hazardous
Substances) Directive bans the use of Lead, Cadmium,
Hexavalent Chromium, Mercury, Polybrominated Biphenyls
(PBB), and Polybrominated Diphenyl Ether (PBDE) in Electrical
and Electronic Equipment. This SynQor product is 6/6 RoHS
compliant. For more information please refer to SynQor’s RoHS
addendum available at our RoHS Compliance / Lead Free
Initiative web page or e-mail us at [e-mail].
Product # NQ04W33xMA16
Phone [phone]
www.synqor.com
Doc.# 005-2NV4V3E Rev. B 11/26/07
Page 12