NQ04W33SKA10 Datasheet, PDF (10/13 Pages) SynQor Worldwide Headquarters – SMT Surface Mount

Technical Specification
Input: 2.4 - 6.0V
Outputs: 0.75 - 3.6V
Current: 10A
Package: SMT
The shutdown point is fixed on standard option. SMA also offers
adjustable OVP set point. For more detailed information 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 Filtering/Capacitance/Damping: The filter circuit of
Figure E is often added to the converter's input to prevent switch-
ing noise from reaching the input voltage bus.
put of the SMA16 series of converters. The VMA16 series has
this capacitance included internally. In many applications, how-
ever, additional external output capacitance is required to reduce
the response to load transients to an allowable level.
The output impedance
of these converters can
be quite accurately
modeled from DC to
about 100kHz as
shown in Figure F. A
further simplified ver-
sion of it, valid below
40Hz and above
1kHz, is shown in
Figure G. In the
Figure F: NQ04 Passive Output Model ^{SMA16 case, the mod-}
els depict the minimum
recommended output capacitance, Ct with its resistance Rt. In
the VMA16 family, that capacitor is again included in the con-
verter.
Figure E: NQ04 converter with Input Filter
In the SMA16 (surface mount) converters Cin = 30µF of high
quality ceramic capacitors. With Lin of 1µH, Cd should be 100-
200µF and Rd should be 0.1-0.2W, in most applications. For
more information on designing the input filter and choosing prop-
er values, contact SynQor technical support.
If the dynamic char-
acteristics of the load
are known, any stan-
dard simulator can
use these models to
predict the in-circuit
transient response.
Figure G: Simplified NQ04 Output Model
Adding significant external pure ceramic capacitance directly
across the converter's input pins is not recommended. Parasitic
inductance associated with the input pin geometry and PCB
traces can create a high-Q CLC circuit with any external capaci-
tors. Just a few nano-Henries of parasitic inductance can create
a resonance (or an overtone) near the converter's switching fre-
quency. Cin has a reactance of 10-20mW at the 300kHz switch-
ing frequency. To avoid this high-frequency resonance, any exter-
nal input filter should exhibit a net source impedance of at least
20mW resistive through this frequency range. This requirement is
easily met with the damping elements discussed above. Adding
a small amount (a few µF) of high-frequency external ceramic will
not violate it.
If using converters at higher powers, consider the ripple current
rating of Cd. Contact SynQor technical support for details.
Output Capacitance: It is recommended to add at least
100µF of capacitance, with an ESR in the 0.1W range, to the out-
Figure H: Converter with Additional Output Capacitance
For minimal overshoot upon recovery, Cd should be related to the
minimum in-circuit net ESR.
Cd > ^{parallel (L1, L2)}
ESRd_min²
For more detailed derivations of these values contact SynQor
technical support.
Product # NQ04W33SKA10
Phone [phone]
www.synqor.com
Doc.# 005-2NK4S3E Rev. A 11/26/07
Page 10