Use an electrolytic capacitor across the input or output if the source
or load inductance is larger than 10 mH. Their equivalent series
resistance together with the capacitance acts as a lossless damping
filter. Suitable capacitor values are in the range of 10–100 mF.
Tantalum capacitors are not recommended due to their low ESR-
value.
Increase VO
+In (pin 18)
Decrease VO
(pin 8)
V
adj
Radj
Radj
Delivery Package Information
Tubes
NOR (pin 9)
Vadj, NOR (pin 8, 9)
Figure 4
The PKF-series is delivered in tubes (designated by /A) with a length
of 500 mm (19.69 in), see fig. 6.
Voltage Margin
For voltage controlled margining e.g. at final test, the following
setup can be used. By increasing the control voltage V1 to +10 V the
output voltage decreases 5% of VOi, and by decreasing V1 to –10 V
the output voltage increases 5%.
Figure 6
Specification
Material:
Max surface resistance:
Color:
Antistatic coated PVC
1011W/
Transparent
Figure 5
Capacity:
Weight:
10 power modules/tube
Typ. 60 g
End stops:
Pins
Capacitive Load
The PKF series has no maximum limit for capacitive load on the
output. The power module may operate in current limiting mode
during start-up, affecting the ramp-up and the start-up time. For
optimum start performance we recommend maximum 100 mF/A of
IO. Connect capacitors at the point of load for best performance.
Trays
SMD versions, SI, can be delivered in standard JEDEC trays (desig-
nated by /B) on request, see fig. 7. For more information, please
contact your local Ericsson sales office.
Parallel Operation
Paralleling of several converters is easily accomplished by direct
connection of the output voltage terminal pins. The load regulation
characteristic is specifically designed for optimal paralleling perform-
ance. Load sharing between converters will be within 10%. It is
,
recommended not to exceed PO = n × 0.9 × POmax where POmax is
the maximum converter output power and n the number of paralleled
converters, to prevent overloading any of the converters and thereby
decreasing the reliability performance.
Current Limiting Protection (Ilim
)
The output power is limited at loads above the output current limit-
ing threshold (Ilim), specified as a minimum value.
Input and Output Impedance
Both the source impedance of the power feeding and the load imped-
ance will interact with the impedance of the DC/DC power module.
It is most important to have the ratio between L and C as low as
possible, i.e. a low characteristic impedance, both at the input and
output, as the power modules have a low energy storage capability.
Figure 7
EN/LZT 146 33 R1A (Replaces EN/LZT 137 09 R7) © Ericsson Microelectronics AB, June 2000
20
ERICSSON [ ERICSSON ]
