Ericsson Internal
EJUNGYA
PRODUCT SPECIFICATION
3 (5)
Prepared (also subject responsible if other)
No.
3/1301-BMR 636 Uen
40
Technical Specification
Approved
Checked
Date
Rev
EN/LZT 146 3R9e4feRre5nDce October 2013
PKB 4000 series
SEC/D (Julia You)
ESHUHAN
2008-1-11
A
© Ericsson AB
DC/DC converters, Input 36-75 V, Output 30 A/90 W
Operating information continued
Thermal Consideration
Parallel Operation
General
Two converters may be paralleled for redundancy if the total
power is equal or less than PO max. It is not recommended to
parallel the converters without using external current sharing
circuits.
The converters are designed to operate in different thermal
environments and sufficient cooling must be provided to
ensure reliable operation.
Cooling is achieved mainly by conduction, from the pins to
the host board, and convection, which is dependant on the
airflow across the converter. Increased airflow enhances the
cooling of the converter.
See Design Note 006 for detailed information.
Remote Sense
The Output Current Derating graph found in the Output
section for each model provides the available output current
vs. ambient air temperature and air velocity at Vin = 53 V.
The DC/DC converters have remote sense that can be used
to compensate for voltage drops between the output and the
point of load. The sense traces should be located close to the
PCB ground layer to reduce noise susceptibility. The remote
sense circuitry will compensate for up to 10% voltage drop
between output pins and the point of load.
The DC/DC converter is tested on a 254 x 254 mm,
35 µm (1 oz), 8-layer test board mounted vertically in a wind
tunnel with a cross-section of 305 x 305 mm.
If the remote sense is not needed +Sense should be
connected to +Out and -Sense should be connected to -Out.
Proper cooling of the DC/DC converter can be verified by
measuring the temperature at positions P1, P2 and P3. The
temperature at these positions should not exceed the max
values provided in the table below.
Over Temperature Protection (OTP)
The converters are protected from thermal overload by the
control IC.
Note that the max value is the absolute maximum rating
(non destruction) and that the electrical Output data is
guaranteed up to Tref +90°C.
When Tref as defined in thermal consideration section
exceeds 135°C the converter will shut down. The DC/DC
converter will make continuous attempts to start up (non-
latching mode) and resume normal operation automatically
when the temperature has dropped >10°C below the
temperature threshold.
See Design Note 019 for further information.
Position
P1
Device
Pcb
Designation
max value
110º C
Over Voltage Protection (OVP)
P2
P3
Mosfet
Mosfet
120º C
120º C
The converters have output over voltage protection that will
shut down the converter in over voltage conditions. The
converter will make continuous attempts to start up (non-
latching mode) and resume normal operation automatically
after removal of the over voltage condition.
Tref
Over Current Protection (OCP)
The converters include current limiting circuitry for protection
at continuous overload.
The output voltage will decrease towards zero for output
currents in excess of max output current (max IO). The
converter will resume normal operation after removal of the
overload. The load distribution should be designed for the
maximum output short circuit current specified.
ERICSSON [ ERICSSON ]
