NQ04W33XMA16 Datasheet, PDF (11/13 Pages) SynQor Worldwide Headquarters – SIP DC/DC converter

Technical Specification
Input: 3.0 - 6.0V
Outputs: 0.75 - 3.6V
Current: 16A
Package: SIP
The shutdown point is fixed on standard option. These convert-
ers also offer adjustable OVP set point. For more detailed infor-
mation contact SynQor technical support.
Over-Temperature Shutdown: A temperature sensor on the
converter senses the average temperature of the module. The
thermal shutdown circuit is designed to turn the converter off
when the temperature at the sensed location reaches the Over-
Temperature Shutdown value. It will allow the converter to turn
on again when the temperature of the sensed location falls by the
amount of the Over-Temperature Shutdown Restart Hysteresis
value.
APPLICATION CONSIDERATIONS
Input and Output Filtering: SynQor recommends an external
input capacitor of either a tantalum, polymer or aluminum elec-
trolytic type on the input of the NQ04 series non-isolated con-
verters. This capacitance and resistance primarily provides
damping of the input filter, reduces the source impedance and
guarantees input stability (see SynQor application note "Input
System Instability"). The input filter is formed by any source or
wiring inductance and the converter’s input capacitance. The
external capacitance also provides an additional benefit of rip-
ple voltage reduction.
A modest sized capacitor would suffice in most conditions, such
as a 330µF, 16V tantalum, with an ESR of approximately 50 mW.
The NiQor family converters have an internal ceramic input
capacitor to reduce ripple current stress on the external capaci-
tors. An external ceramic capacitor of similar size (330µF) with
a series resistor of approximately 50 mW would also suffice and
would provide the filter damping.
Additional ceramic capacitance may be needed on the input, in
parallel with the tantalum capacitor, to relieve ripple current
stress on the tantalum capacitors. The external capacitance forms
a current divider with the 40µF internal ceramic capacitance. At
300 kHz., the impedance of the internal capacitance is about
15mW capacitive. At that frequency, an SMT 330µF tantalum
capacitor would have an impedance of about 50mW resistive,
essentially just the ESR.
In this example, at full load, that would stress the tantalum input
capacitor to about 3A rms ripple current, possibly beyond its rat-
ing. Placing an additional 40µF of ceramic in parallel with that
capacitor would reduce the ripple current to about 1.5A, proba-
bly within its rating at 85^oC. The input ripple current is propor-
tional to load current, so this example should be scaled down
according to the actual load current.
Additional input capacitance equal to half of the output capaci-
tance is recommended when operating with more than 1000uF
of output capacitance on lower voltage outputs when trimming
down by more than half of the trim-down allowance (e.g., further
than -2.5% on a 0.9V, or -5% on a 1.2V).
Input inductance should be reduced for maintaining input stabili-
ty when operating with large output capacitance (>1000µF).
Reducing input inductance to <0.3µH provides for good phase
margin with up to the 4000µF maximum output capacitance. If
the input inductance must be increased up to 1µH even with large
output capacitance (>1000µF), an input capacitance equal to or
greater than the output capacitance may be needed to compen-
sate the input impedance.
If no inductor is used to isolate the input ripple of the NiQor con-
verters from the source or from inputs of other NiQor converters,
then this external capacitance might be provided by the DC/DC
converter used as the power source. SynQor's PowerQor series
converters typically have tantalum and ceramic output capacitors
that would provide the damping.
An input inductor would help isolate the ripple currents and volt-
ages from the source or other NiQor style converters on the volt-
age supply rail. If an input inductor is used, the recommended
capacitance should guarantee stability and control the ripple cur-
rent for up to 1.0µH of input inductance.
The input inductor need not have very high inductance. A value
of 250 nanohenries would equate to almost 500 miliohm of
series impedance at the switching frequency of 300 kHz. This
would be working against an assumed capacitive ESR of 30mW
on the supply side of the inductor, providing significant isolation
and ripple reduction.
No external capacitance is required at the output, however, the
ripple voltage can be further reduced if ceramic and tantalum
capacitors are added at the output. Since the internal output
capacitance is about 50µF, approximately that amount of ceram-
ic capacitance would be needed to produce a noticeable reduc-
tion in output ripple. The value of the tantalum capacitors is both
to provide a high capacitance for pulsed loads and to provide
damping of the distribution network with their inherent ESR,
which is low, but higher than ceramics. Additional output capac-
itance in the range of 300-500µF is beneficial for reducing the
deviation in response to a fast load transient.
Input Over-Voltage Prevention: The power system design-
er must take precautions to prevent damaging the NiQor con-
verters by input overvoltage. This is another reason to be careful
about damping the input filter so that no ringing occurs from an
underdamped filter. The voltage must be prevented from exceed-
ing the absolute maximum voltage indicated in the Electrical
Product # NQ04W33xMA16
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Doc.# 005-2NV4V3E Rev. B 11/26/07
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