EN/LZT 146 09 R1A © Ericsson Microelectronics AB, June 2000

15

EMC Specifications

The conducted EMI measurement was performed using a module

placed directly on the test bench.

Output ripple is measured as the peak to peak voltage of the funda-

mental switching frequency.

Conducted EMI Input terminal value (typ)

Over Voltage Protection (OVP)

The remote control can also be utilized for OVP by using the external

circuitry in fig. 2. Resistor values given are for 5 V output applica-

tions, but can easily be adjusted for other output voltages and the

desired OVP level.

Maximum Capacitive Load

The maximum recommended capacitance connected directly to the

PKA DC/DC power modules’ output, without resistance or inductance

in series, is 100

across the load for maximum effectiveness and maximum stability

margins.

The input voltage is monitored and the PKA DC/DC power module

will turn on and turn off at predetermined levels. The levels can be

decreased by means of an external resistor connected between pin 1

and pin 4.

A 200 k

may be necessary to decrease the load.

Operating information

Remote Control (RC)

Turn-on or turn-off can be realized by using the RC-pin. Normal

operation is achieved if pin 1 is open (NC). If pin 1 is connected to pin

3 the PKA DC/DC power module turns off. To ensure safe turn-off the

voltage difference between pin 1 and 3 shall be less than 1.8 V. RC is

TTL open collector compatible (see fig. 1). Pin 1 is an output and no

current should be driven into pin 1. Use a diode if necessary e.g. totem

pole TTL logic. The internal pull-up resistance is 36 k

W

.

Fig. 1

RC

(pin 1)

TTL

PKA

Control

Logic

-VI

+VI

-In

(pin 3)

Test Set-up according to CISPR publ. 1A

.

5

50

Fig. 2

6

7

9

8

10

5

4

1

3

Parallel Operation

Due to the current limiting protection (hick-up), temperature coeffi-

cient and output voltage characteristic for PKA paralleling of modules

for increased power is not recommended. PKA can be paralleled for

redundancy.

The output voltage adjust function is not accurate and it is recom-

mended to use a potentiometer. To decrease the output voltage the

resistor should be connected between pin 10 and pin 9 (+ Out 1). To

increase the output voltage the resistor should be connected between

pin 10 and pin 8 (– Out 1).

Current LimitingProtection

The output power is limited at loads above the output current limiting

As the PKA multiple output models are power limited, current limit-

ing threshold for an individual output is set by the loads on the other

outputs. The power module can withstand continuous short circuit

without destruction. A hick-up mode is used on all models to mini-

mize the internal power dissipation. The hick-up time constant is set

by the slow start.