Data Sheet
12V TLynxTM: Non-isolated DC-DC Power Modules
July 24, 2009
4.5 – 14Vdc input; 0.69Vdc to 5.5Vdc output; 20A output current
Test Configurations
Design Considerations
Input Filtering
CURRENT PROBE
TO OSCILLOSCOPE
The 12V TLynxTM module should be connected to a
low ac-impedance source. A highly inductive source
LTEST
VIN(+)
1μH
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.
CIN
CS 1000μF
Electrolytic
2x100μF
Tantalum
E.S.R.<0.1Ω
To minimize input voltage ripple, low-ESR polymer
and ceramic capacitors are recommended at the input
of the module.
@ 20°C 100kHz
COM
NOTE: Measure input reflected ripple current with a simulated
source inductance (LTEST) of 1μH. Capacitor CS offsets
possible battery impedance. Measure current as shown
above.
To minimize input voltage ripple, ceramic capacitors
are recommended at the input of the module. Figure
40 shows the input ripple voltage for various output
voltages at 20A of load current with 2x22 µF or 3x22
µF ceramic capacitors and an input of 12V.
Figure 37. Input Reflected Ripple Current Test
Setup.
300
COPPER STRIP
2x22uF
250
3x22 uF
RESISTIVE
Vo+
LOAD
200
10uF
0.1uF
150
100
50
COM
SCOPE USING
BNC SOCKET
GROUND PLANE
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.
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Output Voltage (Vdc)
Figure 40. Input ripple voltage for various
Figure 38. Output Ripple and Noise Test Setup.
output voltages with 2x22 µF or 3x22 µF ceramic
capacitors at the input (20A load). Input voltage
is 12V.
Rdistribution Rcontact
Rcontact Rdistribution
VIN(+)
VO
Output Filtering
The 12V TLynxTM modules are designed for low output
ripple voltage and will meet the maximum output ripple
specification with 0.1 µF ceramic and 10 µF ceramic
capacitors at the output of the module. 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.
RLOAD
VO
VIN
Rdistribution Rcontact
Rcontact Rdistribution
COM
COM
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 39. Output Voltage and Efficiency Test
Setup.
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
polymer and ceramic capacitors are recommended to
improve the dynamic response of the module. Figure
41 provides output ripple information for different
VO. IO
Efficiency
=
x
100 %
η
VIN. IIN
LINEAGE POWER
13
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
