Ericsson Internal
PRODUCT SPECIFICATION
3 (6)
Prepared (also subject responsible if other)
No.
MPM/BK Gran Persson
3/1301-BMR 602 Uen
Approved
Checked
Date
Rev
Reference
MPM/BK (Natalie Johansson)
(MICRF)
2007-05-10
E
Operating information continued
Output Voltage Adjust (Vadj)
The DC/DC converters have an Output Voltage Adjust pin
(Vadj). This pin can be used to adjust the output voltage above
or below Output voltage initial setting.
When increasing the output voltage, the voltage at the output
pins (including any remote sense compensation ) must be
kept below the threshold of the over voltage protection, (OVP)
to prevent the converter from shutting down. At increased
output voltages the maximum power rating of the converter
remains the same, and the max output current must be
decreased correspondingly.
To increase the voltage the resistor should be connected
between the Vadj pin and +Sense pin. The resistor value of the
Output voltage adjust function is according to information
given under the Output section for the respective product.
To decrease the output voltage, the resistor should be
connected between the Vadj pin and —Sense pin.
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 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 >5°C below the
temperature threshold.
Over Voltage Protection (OVP)
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, hiccup) and resume normal operation
automatically after removal of the over voltage condition.
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). If the
output voltage decreases down to 0.5-0.6 V the converter
shuts down and will make continuous attempts to start up
(non-latching mode, hiccup). 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.
Pre-bias Start-up
The product has a Pre-bias start up functionality and will not
sink current during start up if a pre-bias source is present at
the output terminals.
Typical Pre-bias source levels for no negative current:
Up to 0.5 V for PKU 4318L (1.2 V)
Up to 0.7 V for PKU 4318H (1.5 V)
Up to 1.0 V for PKU 4418G (1.8 V)
Up to 1.5 V for PKU 4319 (2.5 V)
Up to 2.0 V for PKU 4510 (3.3 V)
Up to 3.0 V for PKU 4511 (5 V)
Up to 6.0 V for PKU 4513 (12 V)
Up to 9.0 V for PKU 4515 (15 V)
E
PKU 4000 PI & SI series
DC/DC converters, Input 36-75 V, Output 25 A/50 W
EN/LZT 146 308 R2B May 2007
Ericsson Power Modules AB
Technical Specication
E
PKU 4000 PI & SI series
DC/DC converters, Input 36-75 V, Output 25 A/50 W
EN/LZT 146 308 R3A May 2007
Ericsson Power Modules AB
Technical Specication
31