GE Industrial Solutions Naos Raptor 3A - Manual (Page 13)

Data Sheet
December 6, 2010 Naos Raptor 3A: Non-isolated DC-DC Power Modules
4.5 – 14Vdc input; 0.59Vdc to 6Vdc Output; 3A output current
LINEAGE POWER 13
Test Configurations
TO OSCILLOSCOPE CURRENT PROBE
L TEST
1μH
B
A
TTE
R
Y
C
S
1000μF
Electrolytic
E.S.R.<0.1 Ω
@ 20°C 100kHz
2x100μF
Tantalum
V
IN
(+)
COM
NOTE: Measure input reflected ripple current with a simulated
source inductance (L
TEST
) of 1μH. Capacitor C
S
offsets
possible battery impedance. Measure current as shown
above.
C IN
Figure 43. Input Reflected Ripple Current Test
Setup.
NOTE: All voltage measurements to be taken at the module
terminals, as shown above. If sockets are used then
Kelvin connections are required at the module terminals
to avoid measurement errors due to socket contact
resistance.
V O (+)
COM
1uF .
RESISTIVE
LOAD
SCOPE
COPPER STRIP
GROUND PLANE
10uF
Figure 44. Output Ripple and Noise Test Setup.
V
O
COM
V
IN
(+)
COM
R
LOAD
R contact R distribution
R contact R distribution R contact
R contact R distribution
R distribution
V
IN
V O
NOTE: All voltage measurements to be taken at the module
terminals, as shown above. If sockets are used then
Kelvin connections are required at the module terminals
to avoid measurement errors due to socket contact
resistance.
Figure 45. Output Voltage and Efficiency Test Setup.
η =
V
O
. I
O
V
IN
. I
IN
x 100 % Efficiency
Design Considerations
Input Filtering
The Naos Raptor 3A module should be connected to
a low ac-impedance source. A highly inductive
source can affect the stability of the module. An input
capacitance must be placed directly adjacent to the
input pin of the module, to minimize input ripple
voltage and ensure module stability.
To minimize input voltage ripple, low-ESR ceramic or
polymer capacitors are recommended at the input of the
module. Figure 46 shows the input ripple voltage for
various output voltages at 3A of load current with 1x10
µF or 1x22 µF ceramic capacitors and an input of 12V.
Input
R
ippl
e Vol
tage
(mVp-
p
)
0
10
20
30
40
50
60
70
80
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
1x10uF
1x22uF
Output Voltage (Vdc)
Figure 46. Input ripple voltage for various output
voltages with 1x10 µF or 1x22 µF ceramic
capacitors at the input (3A load). Input voltage is
12V.
Output Filtering
The Naos Raptor 3A modules are designed for low
output ripple voltage and will meet the maximum output
ripple specification with no external capacitors.
However, additional output filtering may be required by
the system designer for a number of reasons. First,
there may be a need to further reduce the output ripple
and noise of the module. Second, the dynamic
response characteristics may need to be customized to
a particular load step change.
To reduce the output ripple and improve the dynamic
response to a step load change, additional capacitance
at the output can be used. Low ESR ceramic and
polymer are recommended to improve the dynamic
response of the module. Figure 47 provides output
ripple information for different external capacitance
values at various Vo and for a load current of 3A. For
stable operation of the module, limit the capacitance to
less than the maximum output capacitance as specified