Datasheet

ADP1864-EVALZ
Rev. A | Page 9 of 12
components are sized. As a general guideline, it is recommended
to set this value around 5%. The Ioutstep specification asks the
user to estimate the largest step in load the regulator will
demand. This in conjunction with the allowable voltage
excursion on load transient (Vstep error) delegates how much
output capacitance is required. If the Ioutstep specification is
not known, entering a 50% load step provides an adequate
design for most applications at the power level the
ADP1864 is
designed to be used.
SELECT COMPONENT VALUES AND SIZES
When starting a new design, it is recommended to reset each of
the pull-down menus to “Auto,” which is at the top of the list for
each option. With these settings, the tool automatically
calculates the most efficient design and provides that solution.
If the user would like to explore how other components affect
various parameters of the system, all the parts of the regulator
except the compensation components can be changed through
the use of the pull-down menus in this section. It should be
noted that the tool provides a bill of materials that maintains all
specifications entered in the previous section when a component
is changed. Accordingly, other component values can change as
well. The feedback resistor selector at the bottom of this section
finds right the combination of resistors to provide the feedback
voltage with the 0.8 V.
POWER DISSIPATION AND TEMPERATURE
This section of the tool provides the user with the power
dissipation of each part at the full rated current at both the
maximum and minimum input voltages. It also provides the
user with the estimated temperature of the
ADP1864, the
MOSFET, the diode, and the inductor. These calculations are
done taking into account the temperature rise due to dissipation
as well as the ambient temperature.
EFFICIENCY
From the power dissipation information calculated in the
previous section, the efficiency across the full load range is
plotted for both maximum and minimum input voltages.
APPLICATION SCHEMATIC
This section provides a schematic of the ADP1864 evaluation
board. The reference designators on the evaluation board match
this schematic.
BOM SUMMARY
The bill of materials summary provides the user with the final
parts list necessary to meet all the requirements entered into the
performance specifications section. Vendors, part numbers,
individual and total area, along with a value for each component
are provided. If no part number is provided, a vital specification
is given instead. The user is to use this specification to find a
part to populate on the board. From this BOM, the user can
modify the shipped configuration to validate design changes.