Data Sheet
Austin MegaLynxTM SMT: Non-Isolated DC-DC Power Modules:
2.7 – 4.0Vdc input; 0.8 to 2.0Vdc Output; 30A output current
October 21, 2009
Output Voltage Programming
Voltage Sequencing
The output voltage of the ATM030 module can be
programmed to any voltage from 0.8dc to 2.0Vdc by
connecting a resistor (shown as Rtrim in Figure 31)
between Trim and GND pins of the module.
Without an external resistor between Trim and GND
pins, the output of the module will be 0.8Vdc. To
calculate the value of the trim resistor, Rtrim for a
desired output voltage, use the following equation:
The Austin MegaLynxTM series of modules include a
sequencing feature that enables users to implement
various types of output voltage sequencing in their
applications. This is accomplished via an additional
sequencing pin. When not using the sequencing
feature, either leave the SEQ pin unconnected or
tied to VIN.
Vo
1200
⎡
⎤
Rtrim
=
−100 Ω
⎢
⎣
⎥
⎦
Vo − 0.80
Rmargin-down
Rtrim is the external resistor in Ω
Austin Lynx or
Lynx II Series
Vo is the desired output voltage
Q2
By using a ±0.5% tolerance trim resistor with a TC
of ±100ppm, a set point tolerance of ±1.5% can be
achieved as specified in the electrical specification.
The POL Programming Tool, available at
Trim
Rmargin-up
www.lineagepower.com under the Design Tools
section, helps determine the required external trim
resistor needed for a specific output voltage.
Rtrim
Q1
VIN(+)
VO(+)
TRIM
GND
Figure 32. Circuit Configuration for margining
Output voltage.
LOAD
ON/OFF
Rtrim
For proper voltage sequencing, first, input voltage is
applied to the module. The On/Off pin of the
module is or tied to GND so that the module is ON
by default. After applying input voltage to the
module, a minimum of 10msec delay is required
before applying voltage on the SEQ pin. After
10msec delay, an analog voltage is applied to the
SEQ pin and the output voltage of the module will
track this voltage on a one-to-one volt bases until
output reaches the set-point voltage. To initiate
simultaneous shutdown of the modules, the SEQ
pin voltage is lowered in a controlled manner.
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.
GND
Figure 31. Circuit configuration to program
output voltage using an external resistor.
Voltage Margining
Output voltage margining can be implemented in
the Austin MegaLynxTM modules by connecting a
resistor, Rmargin-up, from the Trim pin to the ground
pin for margining-up the output voltage and by
connecting a resistor, Rmargin-down, from the Trim pin
to output pin for margining-down. Figure 32 shows
the circuit configuration for output voltage
margining. The POL Programming Tool, available
at www.lineagepower.com under the Design Tools
section, also calculates the values of Rmargin-up and
Rmargin-down for a specific output voltage and %
margin. Please consult your local Lineage Power
technical representative for additional details.
When using the EZ-SEQUENCETM feature to
control start-up of the module, pre-bias immunity
feature during start-up is disabled. The pre-bias
immunity feature of the module relies on the module
being in the diode-mode during start-up. When
using the EZ-SEQUENCETM feature, modules goes
through an internal set-up time of 10msec, and will
be in synchronous rectification mode when voltage
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