GE Industrial Solutions PicoTLynx 3A - Manual (Page 11)

GE
Data Sheet
PicoTLynx TM 3A: Non-Isolated DC-DC Power Modules
2.4Vdc –5.5Vdc input; 0.6Vdc to 3.63Vdc output; 3A Output Current
September 11, 2013 ©2013 General Electric Company. All rights reserved. Page 11
Test Configurations
TO OSCILLOSCOPE CURRENT PROBE
L TEST
1μH
BATT
E
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 31. 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.
Vo+
COM
0.1uF
RESISTIVE
LOAD
SCOPE USING
BNC SOCKET
COPPER STRIP
GROUND PLANE
10uF
Figure 32. 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 33. Output Voltage and Efficiency Test Setup.
η =
V
O
. I
O
V
IN
. I
IN
x 100 % Efficiency
Design Considerations
Input Filtering
The Pico TLynx TM 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 capacitors
are recommended at the input of the module. Figure 34 shows
the input ripple voltage for various output voltages at 3A of
load current with 1x22 µF or 2x22 µF ceramic capacitors and
an input of 5V. Figure 35 shows data for the 3.3Vin case, with
1x22µF or 2x22µF of ceramic capacitors at the input.
Input Rippl
e Vol
tag
e
(mVp-p)
0
10
20
30
40
50
60
0.5 1 1.5 2 2.5 3 3.5
1x22uF
2x22uF
Output Voltage (Vdc)
Figure 34. Input ripple voltage for various output voltages
with 1x22 µF or 2x22 µF ceramic capacitors at the input (3A
load). Input voltage is 5V.
Input Ri
pp
le
Vol
tag
e
(m
Vp
-p
)
0
10
20
30
40
50
60
0.5 1 1.5 2 2.5 3
1x22uF
2x22uF
Output Voltage (Vdc)
Figure 35. Input ripple voltage in mV, p-p for various output
voltages with 1x22 µF or 2x22 µF ceramic capacitors at the
input (3A load). Input voltage is 3.3V.