E
ESKEVIN
3/1301-BMR 637 02 Uen
214
Technical Specification
Approved
Checked
Date
Rev
EN/LZT 146 3R0e6feRre4nAceJuly 2008
PKM 4000D PINB Series
SEC/D (Julia You)
EYINGJI
2007-12-10
B
© Ericsson Power Modules AB
DC/DC converters, Input 36-75 V, Output 40 A/132 W
is not required when powering the DC/DC converter from a
low impedance source with short, low inductance, input
power leads.
Operating information
Input Voltage
The input voltage range 36 to 75Vdc meets the requirements
of the European Telecom Standard ETS 300 132-2 for normal
input voltage range in —48 and —60 Vdc systems, -40.5 to -
57.0 V and —50.0 to -72 V respectively. At input voltages
exceeding 75 V, the power loss will be higher than at normal
input voltage and Tref must be limited to absolute max
+110°C. The absolute maximum continuous input voltage is
80Vdc.
External Decoupling Capacitors
When powering loads with significant dynamic current
requirements, the voltage regulation at the point of load can
be improved by addition of decoupling capacitors at the load.
The most effective technique is to locate low ESR ceramic
and electrolytic capacitors as close to the load as possible,
using several parallel capacitors to lower the effective ESR.
The ceramic capacitors will handle high-frequency dynamic
load changes while the electrolytic capacitors are used to
handle low frequency dynamic load changes. Ceramic
capacitors will also reduce any high frequency noise at the
load.
Turn-off Input Voltage
The PKM 4000DSeries DC/DC converters monitor the input
voltage and will turn on and turn off at predetermined levels.
The minimum hysteresis between turn on and turn off input
voltage is 1 V.
It is equally important to use low resistance and low
inductance PCB layouts and cabling.
External decoupling capacitors will become part of the
control loop of the DC/DC converter and may affect the
stability margins. As a “rule of thumb”, 100 μF/A of output
current can be added without any additional analysis. The
ESR of the capacitors is a very important parameter. Power
Modules guarantee stable operation with a verified ESR value
of >10 mΩ across the output connections.
Remote Control (RC)
The products are fitted with a
remote control function referenced
to the primary negative input
connection (- In), with negative and
positive logic options available. The
RC function allows the converter to
be turned on/off by an external
device like a semiconductor or
mechanical switch. The RC pin has
an internal pull up resistor to + In.
For further information please contact your local Ericsson
Power Modules representative.
Output Voltage Adjust (Vadj
)
All PKM 4000DSeries 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 offset) must be kept below
the maximum output adjust range. Also note that at increased
output voltages the maximum power rating of the converter
remains the same, and the output current capability will
decrease correspondingly.
To decrease the output voltage the resistor should be
connected between Vadj pin and —Sense pin. To increase the
voltage the resistor should be connected between Vadj pin
and +Sense pin. The resistor value of the Output voltage
adjust function is according to information given under the
output section.
The maximum required sink current is 1 mA. When the RC pin
is left open, the voltage generated on the RC pin is 3.5 — 6.0
V.
The second option is “positive logic” remote control, which
can be ordered by adding the suffix “P” to the end of the part
number. The converter will turn on when the input voltage is
applied with the RC pin open. Turn off is achieved by
connecting the RC pin to the - In. To ensure safe turn off the
voltage difference between RC pin and the - In pin shall be
less than 1V. The converter will restart automatically when
this connection is opened.
See Design Note 021 for detailed information.
Input and Output Impedance
The impedance of both the power source and the load will
interact with the impedance of the DC/DC converter. It is
most important to have a low characteristic impedance, both
at the input and output, as the converters have a low energy
storage capability. The PKM 4000DSeries DC/DC converters
have been designed to be completely stable without the need
for external capacitors on the input or the output circuits. The
performance in some applications can be enhanced by
addition of external capacitance as described under
maximum capacitive load. If the distribution of the input
voltage source to the converter contains significant
inductance, the addition of a 100μF capacitor across the
input of the converter will help insure stability. This capacitor
ERICSSON [ ERICSSON ]
