Ericsson Internal
PRODUCT SPECIFICATION
3 (5)
Prepared (also subject responsible if other)
No.
HF/MPM/BY/P Anders Wgmark
3/1301-BMR623
Approved
Checked
Date
Rev
Reference
HF/MPM/BY/P (Anders Wgmark)
(MICHEBO)
2007-06-04
A
Operating information continued
Parallel Operation
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.
See Design Note 006 for detailed information.
Remote Sense
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.
If the remote sense is not needed +Sense should be
connected to +Out and -Sense should be connected to -Out.
Over Temperature Protection (OTP)
The converters are protected from thermal overload by an
internal over temperature shutdown circuit.
When Tref P1 as defined in thermal consideration section
exceeds 135°C the converter will shut down immediately
(latching). The DC/DC converter can be restarted by cycling
the input voltage or using the remote control function.
Over Voltage Protection (OVP)
The converters have latching output over voltage protection
that immediately will shut down the converter in over voltage
conditions. The DC/DC converter can be restarted by cycling
the input voltage or using the remote control function.
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.
Thermal Consideration
General
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.
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 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.
Proper cooling of the DC/DC converter can be verified by
measuring the temperature at positions {P1 and P2}. The
temperature at these positions should not exceed the max
values provided in the table below.
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.
See Design Note 019 for further information.
Position
Device
Designation
max value
P1
Pcb
Tsurface
125 C
P2
Transformer
Tcore
125 C
Airflow
E
PKJ 4110E PI
DC/DC converters, Input 36-75 V, Output up to 30 A/100 W
EN/LZT 146 383 R1A June 2007
Ericsson Power Modules AB
Technical Specication
10