Questions tagged [derating]
The derating tag has no usage guidance.
24
questions
1
vote
1answer
38 views
For calculating inrush current in a ceramic capacitor , do we need to consider the effective capacitance after derating for dc-bias effect?
Inrush current happens when capacitor is initially charged from 0V to the intended rail voltage.
What should be the effective capacitance to be considered during this charging? -Since the voltage ...
0
votes
2answers
56 views
Resistor power rating and circuit stability
I've read the following excerpt from a book (Passive Circuit Analysis with LTSpice by Colin May page 96) but am not sure what that means (with no relevant explanation before nor after):
On Fixed ...
0
votes
1answer
62 views
Do touchstone (s2p) files for capacitors from include the ESR/ESL, or do I need to add an ideal R/L for simulation?
Manufacturers like muRata and AVX provide .s2p files for their RF capacitors.
When modeling for simulation in my EDI software, do I need to include the ESR graphed in the datasheet for the frequency ...
-3
votes
1answer
233 views
surge voltage characteristics of ceramic capacitors
I am reading a datasheet from Murata for a ceramic capacitor. According to the datasheet:
When AC voltage or pulse voltage is applied, the
peak-to-peak voltage shall not exceed the rated
DC ...
1
vote
2answers
409 views
Zener temperature derating
Can someone explain what the Ta line on this zener diode temperature derating graph means please.
The diode is an MCC SMBJ5338B 5.1V 5W zener. I understand the lead temperature (TL) line means ...
8
votes
2answers
2k views
Ceramic Capacitors vs DC Bias - Derating rule of thumb misleading?
Premise
Ceramic capacitors with Class 2 dielectrics (such as X5R and X7R) usually show a reduction of its capacitance value as the applied bias voltage increases. This behavior is more prominent in ...
0
votes
1answer
49 views
Determining Absolute Maximums for IC Output Current and Power
I'm having a small gap in understanding with a project I'm working on. The project is reliability related and requires looking at the absolute maximum values for some 54ALS family logic (Max Vcc, ...
2
votes
1answer
321 views
X5R capacitor derating and highpass filters
X5R capacitors derate to about roughly 85% when DC voltage is applied, from what I have been told.
Does this have an effect on high pass filters, even though HF filters off DC (0Hz)?
If I wanted to ...
0
votes
1answer
3k views
Calculating SMD resistor temperature rise
I am interested in knowing the actual power dissipation of an SMD resistor at a 70C ambient temperature. I am looking at a 10kOhm 2512 1Watt resitor RMCF2512JT10K0.
from the electrical specifications ...
0
votes
1answer
117 views
De-rating / Re-rating criteria/theory for frequency in circuit breakers
I'm trying to spec a circuit breaker for a system that will be performing in the 3kHz range, and am not finding much info on how to calculate a new rating based on frequencies in this range (where ...
0
votes
1answer
573 views
common mode choke and derating vs current
I have a CMC that has is rated at about 1kR at 100Mhz at 3A
However my circuit uses only 1A. Do I need to derate my inductance since there is less current flowing through it ?
1
vote
2answers
651 views
How fast do tantalum capacitors self-heal? [closed]
I am troubleshooting a design that uses a 47 µF 20 V tantalum SMD cap across a 15 Vdc rail.
While the derating guidelines I follow dictate a 50% voltage derating for tantalum caps, the design I'm ...
1
vote
1answer
453 views
Correct LED derating
I am currently looking at the datasheet of a LED and have snipped out the passage of interest.
The question is how do I find out the intensity I can reach at a specific temperature/current by using ...
1
vote
3answers
1k views
EEE-INST-002 Wire Derating - Single Wire vs. Bundle/Multi-Conductor
We have an aerospace application and are having trouble defining EEE-INST-002's current derating guidelines in regards to wire.
The issue that I have isn't about stranded versus solid. MIL-W-22759 ...
15
votes
3answers
2k views
Resistor surge rating
I have a circuit with a 220uF capacitor and a resistor is used to limit the inrush current
I stupidly fitted the wrong power rating resistor and (no surprise it failed) its taken me a while to realise ...
8
votes
1answer
11k views
How to derate a ceramic capacitor for DC bias
I understand that the capacitance of a ceramic cap is very dependent on the DC bias applied to the terminals. At rated voltage, I've measured a decrease of up to 70%, and I've heard it can go higher. ...
1
vote
1answer
221 views
Using a COTS common mode choke on DC
Are commercially available common-mode chokes, such as one you'd pull out of a dead switching supply, suitable for DC service up to their rated current, or will they saturate/do other baleful things ...
4
votes
1answer
154 views
How do I derate paralleled diodes with negative temperature coeffecients?
In my application, my load current is 1.4 amps, and for reasons of cost, availability, and recovery time, I want to use this particular 1 amp diode. Like many diodes, this one has a negative ...
0
votes
1answer
595 views
Power resistor derating
I'm going to use a power resistor which needs to dissipate around 2.5W. I will use a resistor rated at 3W.
I have a thermal impedance of 88°C/W. If the ambient is at 40°C, I assume that the resistor ...
4
votes
2answers
140 views
Have bypass cap recommendations already taken derating into consideration?
Datasheets often specify specific values for bypass caps. My assumption is that these values reflect the actual value (after derating), however, I often see on evaluation boards the same nominal value ...
0
votes
1answer
423 views
Busbar calculation
I am looking formula and factor involved in calculating DCDB and ACDB busbar calculation in string combiner box. Please share link or example calculating bus bar.
choosing proper bus bar
effect of ...
0
votes
1answer
86 views
Which BJT-parameters need to be derated at raised ambient temperature?
I am designing a discrete MOSFET-driver stage based on BJTs in simple push-pull configurations and wondering, which of the values under absolute maximum ratings I have to derate at higher ambient ...
0
votes
1answer
1k views
How to do derating analysis
I need help in learning derating analysis for a vienna rectifier circuit (may be anything). Do you guys suggest any material to do the derating analysis by hand for each component understanding the ...
12
votes
3answers
14k views
What does derating mean?
Derating as the Wiki and other Google articles says operating the part at lower values than rated specifications to prolong its life.
Can some please explain "What exactly is Derating?"
How it is ...
