Data Sheet
January 11, 2012
20A Analog Micro DLynxTM: Non-isolated DC-DC Power Modules
3 – 14.4Vdc input; 0.6Vdc to 5.5Vdc output; 20A output current
LINEAGE POWER 15
The output voltage of the modules tracks the voltages
below their set-point voltages on a one-to-one basis.
A valid input voltage must be maintained until the
tracking and output voltages reach ground potential.
Overcurrent Protection
To provide protection in a fault (output overload)
condition, the unit is equipped with internal
current-limiting circuitry and can endure current limiting
continuously. At the point of current-limit inception, the
unit enters hiccup mode. The unit operates normally
once the output current is brought back into its
specified range.
Overtemperature Protection
To provide protection in a fault condition, the unit is
equipped with a thermal shutdown circuit. The unit will
shut down if the overtemperature threshold of 120oC
(typ) is exceeded at the thermal reference point Tref.
Once the unit goes into thermal shutdown it will then
wait to cool before attempting to restart.
Input Undervoltage Lockout
At input voltages below the input undervoltage lockout
limit, the module operation is disabled. The module
will begin to operate at an input voltage above the
undervoltage lockout turn-on threshold.
Synchronization
The module switching frequency can be synchronized
to a signal with an external frequency within a
specified range. Synchronization can be done by using
the external signal applied to the SYNC pin of the
module as shown in Fig. 45, with the converter being
synchronized by the rising edge of the external signal.
The Electrical Specifications table specifies the
requirements of the external SYNC signal. If the SYNC
pin is not used, the module should free run at the
default switching frequency. If synchronization is not
being used, connect the SYNC pin to GND.
MODULE
SYNC
GND
+
Figure 45. External source connections to
synchronize switching frequency of the module.
Dual Layout
Identical dimensions and pin layout of Analog and
Digital Micro DLynx modules permit migration from one
to the other without needing to change the layout. In
both cases the trim resistor is connected between trim
and signal ground.
Power Good
The module provides a Power Good (PGOOD) signal
that is implemented with an open-drain output to
indicate that the output voltage is within the regulation
limits of the power module. The PGOOD signal will be
de-asserted to a low state if any condition such as
overtemperature, overcurrent or loss of regulation
occurs that would result in the output voltage going
±10% outside the setpoint value. The PGOOD terminal
can be connected through a pullup resistor (suggested
value 100KΩ) to a source of 5VDC or lower.
Tunable LoopTM
The module has 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.
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. 46. This R-C allows the user
to externally adjust the voltage loop feedback
compensation of the module.
Figure. 46. Circuit diagram showing connection of
RTUME 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
RTUNE 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
VS+
MODULE
SIG_GND
TRIM
VOUT
RTune
CTune
RTrim
CO
GND