Preliminary Data Sheet
January 19, 2012
3A Analog Pico DLynxTM: Non-isolated DC-DC Power Modules
3 – 14.4Vdc input; 0.6Vdc to 5.5Vdc output; 3A output current
Tunable LoopTM
to be provided in the layout. For the digital modules,
the resistor is connected between the TRIM pad and
SGND and in the case of the analog module it is
connected between TRIM and GND
The 3A Pico DLynxTM modules have a feature that
optimizes transient response of the module called
Tunable LoopTM
.
External capacitors are usually added to the output of
the module for two reasons: to reduce output ripple
and noise (see Figure 38) and to reduce output voltage
deviations from the steady-state value in the presence
of dynamic load current changes. Adding external
capacitance however affects the voltage control loop of
the module, typically causing the loop to slow down
with sluggish response. Larger values of external
capacitance could also cause the module to become
unstable.
MODULE
(PVX003 / PDT003)
TRIM
Rtrim1
for
Digital
Rtrim2
for
Analog
SIG_GND
GND
Caution
– Do not connect SIG_GND to GND
The Tunable LoopTM allows the user to externally
adjust the voltage control loop to match the filter
network connected to the output of the module. The
Tunable LoopTM is implemented by connecting a series
R-C between the SENSE and TRIM pins of the
module, as shown in Fig. 45. This R-C allows the user
to externally adjust the voltage loop feedback
compensation of the module.
elsewhere in the layout
Figure 44. Layout to support either Analog or
Digital PicoDLynx on the same pad.
VOUT
SENSE
RTUNE
C O
MODULE
CTUNE
TRIM
RTrim
GND
Figure. 45. Circuit diagram showing connection of
R
TUME and CTUNE to tune the control loop of the
module.
Recommended values of RTUNE and CTUNE for different
output capacitor combinations are given in Tables 2
and 3. Table 2 shows the recommended values of
R
TUNE and CTUNE for different values of ceramic output
capacitors up to 1000uF that might be needed for an
application to meet output ripple and noise
requirements. Selecting RTUNE and CTUNE according to
Table 2 will ensure stable operation of the module.
In applications with tight output voltage limits in the
presence of dynamic current loading, additional output
capacitance will be required. Table 3 lists
recommended values of RTUNE and CTUNE in order to
meet 2% output voltage deviation limits for some
common output voltages in the presence of a 1.5A to
3A step change (50% of full load), with an input
voltage of 12V.
LINEAGE POWER
15
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
