Technical Reference Notes (TRN)

AA05E Series

36 Vdc to 75 Vdc Inputs, 5 W

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ASTEC POWER - Andover

5 of 8

2.6

Test Configurations

Note: Measure input reflected-ripple current with a simulated source inductance (Ltest) of 12 uH. Capacitor

Cs offsets possible battery impedance. Measure current as shown above.

Figure 1. Input Reflected-ripple Test Setup.

Note: Use a 0.10 uF ceramic capacitors. Scope measurement should be made using a BNC socket. Position

the load between 51 mm and 76 mm (2 in. and 3 in. ) from module.

Figure 2. Peak-to-Peak Output Noise Measurement Test Setup.

3.0

Thermal Considerations

The power module operates in a variety of thermal environments; however, sufficient cooling

should be provided to help ensure reliable operation of the unit. Heat-dissipating components

inside the unit are thermally coupled to the case. Heat is removed by conduction, convection, and

radiation to the surrounding environment.

Increasing airflow over the module enhances the heat transfer via convection. Figure 3 shows the

maximum power that can be dissipated by the module without exceeding the maximum case

temperature versus local ambient temperature (Ta) for natural convection through 3.0 m/s (600

ft/min).

Systems in which these power modules are used typically generate natural convection airflow

rates of 0.25 m/s (50 ft/min) due to other heat dissipating components in the system. Therefore,

the natural convection condition represents airflow rates of approximately 0.25 m/s (50 ft/min).

Use of Figure 3 is shown in the following example:

BATTERY

Cs 220 uF

ESR < 0.1 OHM

@ 20 ºC, 100 kHz

Ltest

12 uH

33 uF

ESR < 0.7 OHM

@ 20 ºC, 100 kHz

Vi(+)

Vi(-)

TO OSCILLOSCOPE

Vo(+)

Vo(-)

RESISTIVE

LOAD

0.10uF

SCOPE

COPPER STRIP