SQ24S08060-PS00G POWER ONE, SQ24S08060-PS00G Datasheet - Page 6

• Manufacturer Part Number: SQ24S08060-PS00G
• Description: Module DC-DC 1-OUT 6V 8A 50W 8-Pin 1/8-Brick
• Manufacturer: POWER ONE
• Type: Step Downr

Specifications of SQ24S08060-PS00G

• Package: 81/8-Brick
• Output Current: 8 A
• Output Voltage: 6 V
• Input Voltage: 24 V
• Number Of Outputs: 1
• Output Power: 50 W

Test Conditions
All data presented were taken with the converter soldered to
a test board, specifically a 0.060” thick printed wiring board
(PWB) with four layers. The top and bottom layers were not
metalized. The two inner layers, comprising two-ounce
copper, were used to provide traces for connectivity to the
converter.
The lack of metalization on the outer layers as well as the
limited thermal connection ensured that heat transfer from
the converter to the PWB was minimized. This provides a
worst-case but consistent scenario for thermal derating
purposes.
All measurements requiring airflow were made in vertical
and horizontal wind tunnel facilities using Infrared (IR)
thermography and thermocouples for thermometry.
Ensuring components on the converter do not exceed their
ratings is important to maintaining high reliability. If one
anticipates operating the converter at or close to the
maximum loads specified in the derating curves, it is prudent
to check actual operating temperatures in the application.
Thermographic imaging is preferable; if this capability is not
available, then thermocouples may be used. Power-One
recommends the use of AWG #40 gauge thermocouples to
ensure measurement accuracy. Careful routing of the
thermocouple leads will further minimize measurement error.
Refer to Figure H for optimum measuring thermocouple
location.
Thermal Derating
Load current vs. ambient temperature and airflow rates are
given in Fig. x.1 for through-hole version. Ambient
temperature was varied between 25 °C and 85 °C, with
airflow rates from 30 to 500 LFM (0.15 to 2.5 m/s), and
vertical and horizontal converter mounting.
For each set of conditions, the maximum load current was
defined as the lowest of:
(i) The output current at which any FET junction temperature
did not exceed a maximum specified temperature (120 °C)
as indicated by the thermographic image, or
(ii) The nominal rating of the converter (4 A on 12 V, 5.3 A
on 8.0 V, 8 A on 6.0 V, 10 A on 5.0 V, and 15 A on
3.3 – 1.0 V).
During normal operation, derating curves with maximum FET
temperature less than or equal to 120 °C should not be
exceeded. Temperature on the PCB at the thermocouple
location shown in Fig. H should not exceed 118 °C in order
to operate inside the derating curves.
MCD10159 Rev. 1.1, 10-Jun-10
18-36 VDC Input; Standard Outputs from 1-12 VDC
Page 6 of 70
SQ24 Series DC-DC Converter Data Sheet
Efficiency
Fig. x.5 shows the efficiency vs. load current plot for ambient
temperature of 25 ºC, airflow rate of 300 LFM (1.5 m/s) with
vertical mounting and input voltages of 18 V, 24 V and 36 V.
Also, a plot of efficiency vs. load current, as a function of
ambient temperature with Vin = 24 V, airflow rate of 200 LFM
(1 m/s) with vertical mounting is shown in Fig. x.6.
Power Dissipation
Fig. x.7 shows the power dissipation vs. load current plot for
Ta = 25 ºC, airflow rate of 300 LFM (1.5 m/s) with vertical
mounting and input voltages of 18 V, 24 V and 36 V. Also, a
plot of power dissipation vs. load current, as a function of
ambient temperature with Vin = 24 V, airflow rate of 200 LFM
(1 m/s) with vertical mounting is shown in Fig. x.8.
Start-up
Output voltage waveforms, during the turn-on transient using
the ON/OFF pin for full rated load currents (resistive load)
are shown without and with external load capacitance in
Fig. x.9 and Fig. x.10, respectively.
Ripple and Noise
Fig. x.13 shows the output voltage ripple waveform,
measured at full rated load current with a 10 µF tantalum
and 1 µF ceramic capacitor across the output. Note that all
output voltage waveforms are measured across a 1 F
ceramic capacitor.
The input reflected ripple current waveforms are obtained
using the test setup shown in Fig x.14. The corresponding
waveforms are shown in Fig. x.15 and Fig. x.16.
Fig. H: Location of the thermocouple for thermal testing.
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