Datasheet

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On/Off 1 can be confi gured by PMBus command MFR_PRIMARY_ON_OFF_
CONFIG (DDh); default confi guration is not ignored; required On/Off 1 control
pin to be asserted to start the unit.
On/Off 2 can be confi gured by PMBus command ON_OFF_CONFIG (02h);
default confi guration is ignored; treat it as always ON.
DBQ's On/Off status is dependent on On/Off 1 control, On/Off 2 control, and
OPERATION (PMBus command) status; all three must be ON to turn DBQ on; if
one of them is OFF, unit will be turned off.
Output Capacitive Load
These converters do not require external capacitance added to achieve rated
specifi cations. Users should only consider adding capacitance to reduce
switching noise and/or to handle spike current load steps. Install only enough
capacitance to achieve noise objectives. Excess external capacitance may
cause degraded transient response and possible oscillation or instability.
Remote Sense Input
Use the Sense inputs with caution. Sense is normally connected at the load.
Sense inputs compensate for output voltage inaccuracy delivered at the load.
Figure 5. Remote Sense Circuit Confi guration
LOAD
Contact and PCB resistance
losses due to IR drops
Contact and PCB resistance
losses due to IR drops
+VOUT
+SENSE
− SENSE
-VOUT
−V IN
ON/OFF
CONTROL
+
V IN
Sense Current
I OUT
Sense Return
I OUT Return
Soldering Guidelines
Murata Power Solutions recommends the specifi cations below when installing these
converters. These specifi cations vary depending on the solder type. Exceeding these
specifi cations may cause damage to the product. Be cautious when there is high atmo-
spheric humidity. We strongly recommend a mild pre-bake (100° C. for 30 minutes). Your
production environment may differ; therefore please thoroughly review these guidelines
with your process engineers.
Wave Solder Operations for through-hole mounted products (THMT)
For Sn/Ag/Cu based solders:
Maximum Preheat Temperature 115° C.
Maximum Pot Temperature 270° C.
Maximum Solder Dwell Time 7 seconds
For Sn/Pb based solders:
Maximum Preheat Temperature 105° C.
Maximum Pot Temperature 250° C.
Maximum Solder Dwell Time 6 seconds
This is done by correcting IR voltage drops along the output wiring and the
current carrying capacity of PC board etch. This output drop (the difference
between Sense and Vout when measured at the converter) should not exceed
0.5V. Consider using heavier wire if this drop is excessive. Sense inputs also
improve the stability of the converter and load system by optimizing the control
loop phase margin.
Note: The Sense input and power Vout lines are internally connected through
low value resistors to their respective polarities so that the converter can
operate without external connection to the Sense. Nevertheless, if the Sense
function is not used for remote regulation, the user should connect +Sense to
+Vout and –Sense to –Vout at the converter pins.
The remote Sense lines carry very little current. They are also capacitively
coupled to the output lines and therefore are in the feedback control loop to
regulate and stabilize the output. As such, they are not low impedance inputs
and must be treated with care in PC board layouts. Sense lines on the PCB
should run adjacent to DC signals, preferably Ground. In cables and discrete
wiring, use twisted pair, shielded tubing or similar techniques.
Any long, distributed wiring and/or signifi cant inductance introduced into the
Sense control loop can adversely affect overall system stability. If in doubt, test
your applications by observing the converter’s output transient response during
step loads. There should not be any appreciable ringing or oscillation. You
may also adjust the output trim slightly to compensate for voltage loss in any
external fi lter elements. Do not exceed maximum power ratings.
Please observe Sense inputs tolerance to avoid improper operation:
[Vout(+) −Vout(-)] − [Sense(+) −Sense(-)] ≤ 5% of Vout
Output overvoltage protection is monitored at the output voltage pin, not the
Sense pin. Therefore excessive voltage differences between Vout and Sense
together with trim adjustment of the output can cause the overvoltage protec-
tion circuit to activate and shut down the output.
Power derating of the converter is based on the combination of maximum
output current and the highest output voltage. Therefore the designer must
ensure:
(Vout at pins) x (Iout)
≤ (Max. rated output power)
DBQ/DVQ Series
420W Digital Fully Regulated Intermediate
DC-DC Bus Converter
MDC_DBQ Series.B02Δ Page 29 of 31