Preliminary Data Sheet
May 25, 2011
3A Digital Pico DLynxTM: Non-isolated DC-DC Power Modules
3 – 14.4Vdc input; 0.45Vdc to 5.5Vdc output; 3A output current
LINEAGE POWER
13
Design Considerations
Input Filtering
The 3A Digital Pico DLynx
TM module should be
connected to a low ac-impedance source. A highly
inductive source can affect the stability of the
module. An input capacitance must be placed
directly adjacent to the input pin of the module, to
minimize input ripple voltage and ensure module
stability.
To minimize input voltage ripple, ceramic capacitors
are recommended at the input of the module. Figure
37 shows the input ripple voltage for various output
voltages at 3A of load current with 2x22 F or 3x22
F ceramic capacitors and an input of 12V.
TBD
Figure 37. Input ripple voltage for various
output voltages with 2x22 F or 3x22 F ceramic
capacitors at the input (3A load). Input voltage is
12V.
Output Filtering
These modules are designed for low output ripple
voltage and will meet the maximum output ripple
specification with 0.1 F ceramic and 22 F ceramic
capacitors at the output of the module. However,
additional output filtering may be required by the
system designer for a number of reasons. First, there
may be a need to further reduce the output ripple and
noise of the module. Second, the dynamic response
characteristics may need to be customized to a
particular load step change.
To reduce the output ripple and improve the dynamic
response to a step load change, additional
capacitance at the output can be used. Low ESR
polymer and ceramic capacitors are recommended to
improve the dynamic response of the module. Figure
38 provides output ripple information for different
external capacitance values at various Vo and a full
load current of 3A. For stable operation of the module,
limit the capacitance to less than the maximum output
capacitance as specified in the electrical specification
table. Optimal performance of the module can be
achieved by using the Tunable Loop
TM feature
described later in this data sheet.
TBD
Figure 38. Output ripple voltage for various output
voltages with external 1x10 F, 1x22 F, 1x47 F or
2x47 F ceramic capacitors at the output (3A load).
Input voltage is 12V.
Safety Considerations
For safety agency approval the power module must be
installed in compliance with the spacing and
separation requirements of the end-use safety agency
standards, i.e., UL 60950-1 2nd, CSA C22.2 No.
60950-1-07, DIN EN 60950-1:2006 + A11 (VDE0805
Teil 1 + A11):2009-11; EN 60950-1:2006 + A11:2009-
03.
For the converter output to be considered meeting the
requirements of safety extra-low voltage (SELV), the
input must meet SELV requirements. The power
module has extra-low voltage (ELV) outputs when all
inputs are ELV.
The input to these units is to be provided with a slow-
blow fuse with a maximum rating of TBD A in the
positive input lead
.