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BLOCK DIAGRAM (Single Output)
designer must assign one of the converters as the
master. Then, by definition, the remaining
converters become slaves and will operate at the
masters' switching frequency. The user should
be aware that the synchronozation system is fail-safe;
that is, the slaves will continue operating should the
master frequency be interrupted for any reason.
The layout must be such that the synchronozation
output (Pin 9) of the master device is connected to
the synchronozation input (Pin 9) of each slave
device. It is advisable to keep this run short to
minimize the possibilty of radiating the 250KHz
switching frequency.
The appropriate parts must be ordered to utilize
this feature. After selecting the converters
required for the system, an ‘MSTR’ suffix is
added for the master converter part number and
an ‘SLV’ suffix is added for slave part number.
APPLICATION INFORMATION
Inhibit Function
Connecting the inhibit input (Pin 2) to input
common (Pin 10) will cause the converter to shut
down. It is recommended that the inhibit pin be
driven by an open collector device capable of
sinking at least 400A of current. The open circuit
voltage of the inhibit input is 11.5 +1 VDC.
EMI Filter
An optional EMI filter (AFC461) will reduce the
input ripple current to levels below the limits
imposed by MIL-STD-461 CEO3.
Device Synchronization
Whenever multiple DC/DC converters are utilized
in a single system, significant low frequency noise
may be generated due to slight difference in the
switching frequencies of the converters (beat
frequency noise). Because of the low frequency
nature of this noise (typically less than 10 KHz), it
is difficult to filter out and may interfere with
proper operation of sensitive systems (communi-
cations, radar or telemetry). Lambda Advanced
Analog offers an option which provides synchroniza-
tion of multiple AHE/ATW converters, thus eliminat-
ing this type of noise.
To take advantage of this capability, the system
INPUT
FILTER
CONTROLLER
1
2
9
10
OUTPUT
FILTER
REGULATOR
& OUTPUT
FILTER
ERROR
AMP
& REF
3
5
4
6