MQFL-28VE-1R8S Datasheet, PDF (12/19 Pages) SynQor Worldwide Headquarters – HIGH RELIABILITY DC-DC CONVERTER

Technical Specification
MQFL-28VE-1R8S
Output: 1.8V
Current: 40A
Inside the converter, +SENSE is connected to +Vout with a resistor
value from 100W to 301W, depending on output voltage, and
–SENSE is connected to OUTPUT RETURN with a 10W resistor
It is also important to note that when remote sense is used, the
voltage across the converter’s output terminals (pins 7 and 8)
will be higher than the converter’s nominal output voltage due
to resistive drops along the connecting wires. This higher volt-
age at the terminals produces a greater voltage stress on the
converter’s internal components and may cause the converter to
fail to deliver the desired output voltage at the low end of the
input voltage range at the higher end of the load current and
temperature range. Please consult the factory for details.
SYNCHRONIZATION: The MQFL converter’s regulation and
isolation stage switching frequencies can be synchronized to an
external frequency source that is in the 500 kHz to 600 kHz
range. The boost-converter stage is free-running at about 670
kHz while it is operational, and is not affected by synchroniza-
tion signals. A pulse train at the desired frequency should be
applied to the SYNC IN pin (pin 6) with respect to the INPUT
RETURN (pin 2). This pulse train should have a duty cycle in the
20% to 80% range. Its low value should be below 0.8V to be
guaranteed to be interpreted as a logic low, and its high value
should be above 2.0V to be guaranteed to be interpreted as a
logic high. The transition time between the two states should be
less than 300ns.
If the MQFL converter is not to be synchronized, the SYNC IN pin
should be left open circuit. The converter will then operate in its
free-running mode at a frequency of approximately 550 kHz.
If, due to a fault, the SYNC IN pin is held in either a logic low
or logic high state continuously, the MQFL converter will revert
to its free-running frequency.
The MQFL converter also has a SYNC OUT pin (pin 5). This
output can be used to drive the SYNC IN pins of as many as ten
(10) other MQFL converters. The pulse train coming out of SYNC
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synchronization signal at the SYNC IN pin, or ₃the synchroniza-
tion frequency if there is.
CASE
The
SYNC
O²⁸U^VT^ds^cign^+–al
is
available
only
when
4
the
vEoNltaAg1e
at
the
STABILITY pin (pin 3) is above approximately₅12V and when
the converter is not inhibited through the ENA1 pi^Sn^Y. ^NA^Cn ^Oin^Uhi^Tbit
through
the
ENA2
pin
will_mon_epao^ennt_s turn
on
the
SYNC
O⁶UT_Ss_Yig_Nn_Cal_INoff.
NOTE: An MQFL converter that has its SYNC IN pin driven by
the SYNC OUT pin of a second MQFL converter will have its
start of its switching cycle delayed approximately 180 degrees
relative to that of the second converter.
Figure B shows the equivalent circuit looking into the SYNC IN
pin. Figure C shows the equivalent circuit looking into the SYNC
OUT pin.
5V
PIN 6
PIN 2
5K
SYNC IN
5K
IN RTN
TO SYNC
CIRCUITRY
Figure B: Equivalent circuit looking into the SYNC IN pin with
respect to the IN RTN (input return) pin.
5V
FROM SYNC
CIRCUITRY
5K
SYNC OUT
OPEN COLLECTOR
OUTPUT
IN RTN
PIN 5
PIN 2
Figure C: Equivalent circuit looking into SYNC OUT pin with
respect to the IN RTN (input return) pin.
CURRENT SHARE: When several MQFL converters are placed
in parallel to achieve either a higher total load power or N+1
redundancy, their SHARE pins (pin 11) should be connected
together. The voltage on this common SHARE node represents the
average current delivered by all of the paralleled converters. Each
converter monitors this average value and adjusts itself so that its
output current closely matches that of the average.
12
Since the SHARE p^ENin^Ais²monitored with respect to the OUTPUT
RthEeTUcoRnNve(prtienrs8’ )ObUy_STeHPaUAcTh_RERcEoTn¹_Uv¹eRrNterp,iintsistoimgeptohretar ntht _{rtooucgohnnaelcotwalDl} oCf
and AC impedance₊. _SW_NShen¹⁰this is done correctly, the converters
wwiiltlhidne+liv/e- r1t0h%eiraat pf_–uplSrl o_NrpaSrteiadt₉elofaradc.tion of the tota_Rtrl_imload current to
Whether or no_Ot _Uco_Tn_Rv_Te_Nrters⁸ are paralleled, the voltage at^– the
SHARE pin could be used ₇to monitor the approximaLteoaadverage
current delivered b+yVOthUe Tconverter(s). A nominal
represents zero current and a nominal voltage of
v2o.l2taVgereporfe1s_+e.0ntVs
the maximum rated current, with a linear relationship in between.
The internal source resistance of a converter’s SHARE pin signal is
2.5 kW. During an input voltage fault or primary disable event, the
SHARE pin outputs a power failure warning pulse. The SHARE pin
will go to 3V for approximately 14ms as the output voltage falls.
Product # MQFL-28VE-1R8S
Phone [phone]
www.synqor.com
Doc.# 005-0005206 Rev. 1
04/22/09
Page 12