Data Sheet
16V Pico TLynxTM 4A: Non-isolated DC-DC Power Modules
8 – 16Vdc input; 0.6Vdc to 8.0Vdc output; 4A output current
September 13, 2010
Test Configurations
Design Considerations
Input Filtering
CURRENT PROBE
TO OSCILLOSCOPE
The 16V Pico TLynxTM 4A 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.
LTEST
VIN(+)
1μH
CIN
CS 1000μF
Electrolytic
2x100μF
Tantalum
E.S.R.<0.1Ω
@ 20°C 100kHz
To minimize input voltage ripple, ceramic
capacitors are recommended at the input of the
module. Figure 52 shows the input ripple voltage
for various output voltages at 4A of load current
with 1x10 µF or 1x22 µF ceramic capacitors and an
input of 12V.
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.
Figure 49. Input Reflected Ripple Current Test
Setup.
350
300
250
200
150
COPPER STRIP
RESISTIVE
Vo+
LOAD
10uF
0.1uF
1x10uF
1x22uF
100
50
COM
SCOPE USING
BNC SOCKET
0
GROUND PLANE
0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
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.
Output Voltage (Vdc)
Figure 52. Input ripple voltage for various output
voltages with 1x10 µF or 1x22 µF ceramic
capacitors at the input (4A load). Input voltage is
12V.
Figure 50. Output Ripple and Noise Test Setup
Rdistribution Rcontact
Rcontact Rdistribution
VIN(+)
VO
Output Filtering
The 16V Pico TLynxTM 4A 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
VIN
VO
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 51. 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
53 provides output ripple information for different
external capacitance values at various Vo and for a
load current of 4A. For stable operation of the module,
limit the capacitance to less than the maximum output
VO. IO
Efficiency
=
x
100 %
η
VIN. IIN
LINEAGE POWER
14
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
