Advance Data Sheet
November 17, 2011
40A Analog Mega DLynx
TM
: Non-isolated DC-DC Power Module
4.5 – 14.4Vdc input; 0.6Vdc to 2Vdc output; 40A output current
module as shown in Fig. 6, 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.
connected across the sequencing voltage before it is
fed to the SEQ pin as shown in Fig. 5.
DLynx Module
V
SEQ
20K
SEQ
R1=Rtrim
100 pF
MODULE
SIG_GND
SYNC
+
─
GND
Figure 5. Circuit showing connection of the
sequencing signal to the SEQ pin.
When the scaled down sequencing voltage is applied
to the SEQ pin, the output voltage tracks this voltage
until the output reaches the set-point voltage. The final
value of the sequencing voltage must be set higher
than the set-point voltage of the module. The output
voltage follows the sequencing voltage on a one-to-
one basis. By connecting multiple modules together,
multiple modules can track their output voltages to the
voltage applied on the SEQ pin.
To initiate simultaneous shutdown of the modules, the
SEQ pin voltage is lowered in a controlled manner.
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.
Figure 6. External source connections to
synchronize switching frequency of the module.
Dual Layout
Identical dimensions and pin layout of Analog and
Digital Mega 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.
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
o
TBD C(typ) is exceeded at the thermal reference point
T
ref
.Once the unit goes into thermal shutdown it will
then wait to cool before attempting to restart.
Tunable Loop
TM
The module has a feature that optimizes transient
response of the module called Tunable Loop
TM
.
External capacitors are usually added to the output of
the module for two reasons: to reduce output ripple
and noise 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 Loop
TM
allows the user to externally
adjust the voltage control loop to match the filter
network connected to the output of the module. The
Tunable Loop
TM
is implemented by connecting a series
R-C between the VS+ and TRIM pins of the module,
as shown in Fig. 7. This R-C allows the user to
8
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
LINEAGE
POWER
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
