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Rockwell Automation Publication 1606-RM124A-EN-P - September 2021
DC/DC Converter - 48V/48V, 5 A, 240 W Reference Manual
Daisy Chaining of Outputs
Daisy chaining (jumping from one DC/DC-converter output to the next) is
permitted, as long as the average output current through one terminal pin
does not exceed 25 A. If the current is higher, use a separate distribution
terminal block.
Lifetime Expectancy
The Lifetime expectancy that is shown in the table indicates the minimum
operating hours (service life) and is determined by the lifetime expectancy of
the built-in electrolytic capacitors. Lifetime expectancy is specified in
operational hours and is calculated according to the capacitor’s manufacturer
specification.
The manufacturer of the electrolytic capacitors only states a maximum life of
up to 15 years (131,400 hr). Any number that exceeds this value is a calculated
theoretical lifetime, which can be used to compare devices.
Mean Time Between Failure
Mean time between failure (MTBF) is calculated according to statistical device
failures, and indicates reliability of a device. The MTBF value is a statistical
representation of the likelihood of a unit to fail and does not necessarily
represent the life of a product. An MTBF value of, for example, 1,000,000 hr
means that statistically one unit fails every 100 hours if 10,000 units are
installed in the field. However, it cannot be determined if the failed unit has
been running for 50,000 hr or only for 100 hr.
For these types of units, the Mean Time to Failure (MTTF) value is the same as
the MTBF value.
Figure 17 - Daisy Chaining of Outputs
Figure 18 - Using Distribution Terminals
Converter
DC/DC
+
+
-
-
+
+
-
-
Input
Converter
DC/DC
Input
Load
+
-
25 A, max
Output
Output
Distribution
Terminals
Converter
DC/DC
+
+
-
-
+
+
-
-
Input
Converter
DC/DC
Input
Load
+
-
Output
Output
Attributes
Input 48V DC Notes
Lifetime expectancy
160,000 hr
At 48V, 5 A, and 40 °C (104 °F)
307,000 hr
At 48V, 2.5 A, and 40 °C (104 °F)
112,000 hr
At 48V, 6 A, and 40 °C (104 °F)
453,000 hr
At 48V, 5 A, and 25 °C (77 °F)
868,000 hr
At 48V, 2.5 A, and 25 °C (77 °F)
318,000 hr
At 48V, 6 A, and 25 °C (77 °F)
Attributes
Input 48V DC Notes
MTBF SN 29500, IEC 61709
853 kHz
At 48V, 5 A, and 40 °C (104 °F)
1512 kHz
At 48V, 5 A, and 25 °C (77 °F)
MTBF MIL HDBK 217F
285 kHz
At 48V, 5 A, and 40 °C (104 °F); Ground Benign GB40
421 kHz
At 48V, 5 A, and 25 °C (77 °F); Ground Benign GB25
71 kHz
At 48V, 5 A, and 40 °C (104 °F); Ground Fixed GF40
97 kHz
At 48V, 5 A, and 25 °C (77 °F); Ground Fixed GF25
