Product # PQ60033HPA70
Phone 1-888-567-9596
www.synqor.com
Doc.# 005-2HP633K Rev. B
07/01/09
Page 10
Input:
Output:
Current:
Package:
35-75V
3.3V
70A
Half-brick
Technical Specification
OUTPUT VOLTAGE TRIM (Pin 8):TheTRIMinputpermitsthe
usertoadjusttheoutputvoltageacrossthesenseleadsupor
downaccordingtothetrimrangespecifications.
To decrease the output voltage, the user should connect a
resistorbetweenPin8andPin7(SENSE(-)input).Foradesired
decreaseofthenominaloutputvoltage,thevalueoftheresistor
shouldbe
Rtrim-down=
(100%)-2(kW)
D
where
D% = Vnominal–Vdesired x100%
Vnominal
To increase the output voltage, the user should connect a
resistorbetweenPin8andPin9(SENSE(+)input).Foradesired
increaseofthenominaloutputvoltage,thevalueoftheresistor
shouldbe
(k
W)
Rtrim-up
=
(Vnominal–2)xVDES+VNOM
1.225
VDES-VNOM
FigureCgraphstherelationshipbetweenthetrimresistorvalue
and Rtrim-up and Rtrim-down, showing the total range the
outputvoltagecanbetrimmedupordown.
Figure C: Trim Graph for 3.3Vout module
Note:theTRIMfeaturedoesnotaffectthevoltageatwhichthe
outputover-voltageprotectioncircuitistriggered.Trimmingthe
outputvoltagetoohighmaycausetheover-voltageprotection
circuittoengage,particularlyduringtransients.
ItisnotnecessaryfortheusertoaddcapacitanceattheTrim
pin.Thenodeisinternallybypassedtoeliminatenoise.
Total DC Variation of Vout:Fortheconvertertomeetitsfull
specifications,themaximumvariationoftheDCvalueofVout,
duetobothtrimmingandremoteloadvoltagedrops,shouldnot
begreaterthanthatspecifiedfortheoutputvoltagetrimrange.
PROTECTIONFEATURES
Input Under-Voltage Lockout: The converter is designed
toturnoffwhentheinputvoltageistoolow,helpingavoidan
inputsysteminstabilityproblem,describedinmoredetailinthe
application note titled “Input System Instability”. The lockout
circuitry is a comparator with DC hysteresis. When the input
voltage is rising, it must exceed the typical Turn-On Voltage
Threshold value (listed on the specification page) before the
converter will turn on. Once the converter is on, the input
voltage must fall below the typical Turn-Off Voltage Threshold
valuebeforetheconverterwillturnoff.
Input Over-Voltage Shutdown: Available on PQ48 models
only. The converter turns off when the input voltage is too
high, allowing the converter to withstand an input voltage as
high as 100V without destruction. The shutdown circuitry is a
comparatorwithDChysteresis.Whentheinputvoltageexceeds
the typical Input Over-Voltage Shutdown value, the converter
willturnoff.Oncetheconverterisoff,itwillturnbackonwhen
the input voltage falls below the minimum Input Over-Voltage
Shutdownvalue.
Output Current Limit: The maximum current limit remains
constant as the output voltage drops. However, once the
impedance of the short across the output is small enough to
make the output voltage drop below the specified Output DC
Current-LimitShutdownVoltage,theconverterturnsoff.
Theconverterthenentersa“hiccupmode”whereitrepeatedly
turnsonandoffata5Hz(nominal)frequencywitha5%duty
cycleuntiltheshortcircuitconditionisremoved.Thisprevents
excessiveheatingoftheconverterortheloadboard.
Output Over-Voltage Limit:Ifthevoltageacrosstheoutput
pinsexceedstheOutputOver-VoltageProtectionthreshold,the
converterwillimmediatelystopswitching.Thispreventsdamage
totheloadcircuitdueto1)excessiveseriesresistanceinoutput
current path from converter output pins to sense point, 2) a
releaseofashort-circuitcondition,or3)areleaseofacurrent
limit condition. Load capacitance determines exactly how high
theoutputvoltagewillriseinresponsetotheseconditions.After
200mstheconverterwillautomaticallyrestart.
Over-Temperature Shutdown: A temperature sensor on
the converter senses the average temperature of the module.
Thethermalshutdowncircuitisdesignedtoturntheconverter
off when the temperature at the sensed location reaches the
Over-Temperature Shutdown value. It will allow the converter
toturnonagainwhenthetemperatureofthesensedlocation
fallsbytheamountoftheOver-TemperatureShutdownRestart
Hysteresisvalue.