Questions tagged [thermal]
Relating to temperature rise, the flow of heat, or cooling of components
575
questions
0
votes
1
answer
24
views
What can I add to a body protector scoring system to be more stable and accurate with hight precision? [closed]
I am developing a Taekwondo body protector scoring system using a textile piezoelectric sensor. The sensor is designed to detect mechanical force and convert it into an electrical charge. However, it ...
1
vote
0
answers
54
views
Difference between Kelvin and Celsius in dynamic thermal behavior of MOSFETs
I am trying to understand the temperature behavior at the junction level and this Application Note "AN_201712_PL11_001" from Infineon describes the process.
The problem is that I have a hard ...
- 79
1
vote
1
answer
21
views
Is it possible to multiplex thermistors for multiple cell battery configurations for the BQ25756 or other JEITA charge ICs for spaced apart cells?
I'm trying to figure out how to safely implement fast charging using the BQ25756 with a most likely 2s (though up to 4s is possible) layout of physically spaced out cells.
I haven't fully decided on ...
0
votes
0
answers
34
views
+50
Understanding thermal instability breakdown in pn junctions
I am currently reading Sze (Physics of Semiconductor Devices, 3e, Chapter 2.4.1) and am trying to understand his discussion of thermal instability breakdown/runaway in pn junctions. I have also ...
- 309
1
vote
1
answer
56
views
PMV20XNER MOSFET Overheating
I am using the PMV20XNER as a simple switch. I am driving a load of about 8 Ω from a 24 V power supply. A schematic is below:
When I apply 3.3 V to the gate (which should be enough to turn this ...
- 13
1
vote
1
answer
98
views
Would a PCB thermo handle a high power LED?
I need to have my Cree T6 5 W LED on the star, on top of my Arduino shield, would that resist the LED heat?
I plan to use thermal adhesive and custom make my shield so is 2 sided, with thermal vias ...
- 1,047
1
vote
1
answer
65
views
Calculating Case-to-Sink thermal resistance from bulk thermal conductivity of thermal pad material
I am using a thermal pad instead of a thermal compound between the mosfet and the heatsink.
Thermal pad (p/n 53-78-1ACG) has a thermal conductivity of 0.9 W/(m-C) and 0.15mm thickness.
Normally I am ...
- 450
10
votes
5
answers
2k
views
Thermal relief for a chip without metal plate on the bottom
I have a chip in which I have selected this footprint: Package_SO: SOIC-8_3.9X4.9mm_P1.27mm.
This is what it looks like:
Because this chip gets pretty hot, I ...
- 1,339
1
vote
2
answers
297
views
What is the general rule for LDO thermal considerations at various voltages?
This question isn't so much about my specific case, but rather, I'm looking for a general rule for estimating the max current that can be pulled from heatsink-less LDOs at some voltage difference.
I ...
- 1,786
0
votes
3
answers
1k
views
Implementing a 5 Watt, Linear Variable DC Power Supply that DOESN'T get burning hot?
The load I am trying to drive is a fan module that includes a DC cooling fan, a tachometer, some status LEDs and other temperature monitoring electronics. Historically users have swapped power ...
- 11
2
votes
0
answers
32
views
Noise floor of an unmatched resistive network thru PSD calculations
I am modeling the PSD of various loads to calculate noise floors. I have various load terminations from 25 ohms to 250 ohms.
Per Johnson-Nyquist, the noise floor on a resistor when load and source are ...
- 21
1
vote
1
answer
48
views
Thermodynamics of a simple electrical conductor
I derived an expression for the time constant of the temperature of an electrical conductor and was looking for some constructive feedback.
Initially there is no current flowing through the conductor ...
- 11
6
votes
3
answers
1k
views
What is the most common electronics IC package material?
I'm trying to make a thermal simulation of a PCB, and one of the parameters I have to put in the simulation software is the component package material. For most standard ICs as far as I know, it's ...
- 156
0
votes
0
answers
32
views
Thermal analysis of a step down regulator
LTM8053 datasheet
I tried to plot the thermal graphic (watt-celcius) for this buck converter in MATLAB. The main goal is to find losses which turn into heat. Reasons for heat most of time switching ...
- 15
8
votes
2
answers
735
views
Entire FPGA getting hot evenly, not just a single hot spot
I have a board with an Altera EPF10K30RC240-4N that is not functioning at all. There is a high current draw on the board. The +5V rail is only 2.6V and there is 4.2 ohms between +5V and GND.
The board ...
- 497
18
votes
1
answer
2k
views
Entire Perimeter of FPGA Getting Hot - Why?
I have a commercially-produced board with an Altera EPF10K30-series FPGA. There is an abnormally high current draw on the board. Where +5V should be present, there is only +2.6V.
When comparing ...
- 497
3
votes
0
answers
36
views
I'm confused about boundary conditions and walls in thermal simulation (using IcePak)
I'm trying to learn a little thermal simulation. I just have a single LED on a board, I made a 3d model for it. And I thought I could use thermal simulation to see how big I need to make the board to ...
- 1,806
2
votes
1
answer
457
views
Kicad 7 - Drill out of range
I had a footprint for a component in Kicad 5. Then i updated to Kicad 7 and I am getting this error:
...
- 1,339
1
vote
1
answer
54
views
Compensating for lack of via-in-pad for buck converter thermal design
I am designing a buck converter, based on a TI chip. Both the datasheet and an excellent document "Five steps to a great PCB layout for a step-down converter" show vias in the exposed pad, ...
- 4,560
0
votes
0
answers
25
views
Thermal Conductance of a Pyroelectric sensor
For some temperature changes, I want to use a pyroelectric sensor. I have been looking for the R.G. Whatmore's papers for the basic theory. In the paper, for calculating the time constant. He ...
- 11
0
votes
1
answer
45
views
Eagle: Adding thermal to QFN components
How to properly place thermal vias under components?
I hook them up to the ground net, the same as the ground pad of my QFN component, but they don't seem to connect.
Do I need to edit the footprint ...
- 480
1
vote
0
answers
54
views
Coupling heatsink RC network to MOSFET's Cauer circuit
I am trying to understand simple RC thermal simulation to analyse the temperature rise in Rohm a 1200 V N-channel SiC MOSFET SCT3040KR.
RC Cauer parameters are as depicted in the LTspice circuit ...
- 21
0
votes
3
answers
63
views
Do I need to apply thermal relief on the 3V3 polygon?
Should I enable thermal relief for the 3V3 (yellow line) polygon? If not, does it imply that the components on the right-hand side will be more difficult to solder due to their connection to a larger ...
- 67
1
vote
0
answers
39
views
LED Multiplexing - Large Matrices - Efficient Selection of Scanline Groups
I have a 4 x 8 matrix of RGB 8-segment displays, (short for a 7-segment 'digit' plus a dot pixel, for which each segment (as well as dot) contains: 1x red LED, 1x ...
- 345
0
votes
4
answers
126
views
Thermal pad to dissipate heat to pc case
My motherboard, at the back of the CPU to be precise, is quite hot. Mine is a X99 with little over clocking. I am thinking if I use a piece of adhesive silicone pad to transfer the heat from the back ...
- 1
0
votes
1
answer
231
views
Do letters matter on thermal fuses?
DIY oven repair question.
I need to replace this thermal fuse:
Does it matter what letters there are shown i.e. YCW.dz YCWRY, <...
- 101
1
vote
3
answers
103
views
How to apply thermal paste on a large surface (between IMS PCB and heatsink)?
I've got a project that features an array of ultraviolet LEDs on an aluminium board.
This board shall be screwed to a heatsink.
My problem is that I'd like to apply thermal paste to improve the ...
- 33
0
votes
0
answers
40
views
How can I compare thermal behaviour between two packages with an equivalent resistors circuit?
I want to make a thermal analysis of QFP and BGA packages for a microcontroller. I know that in terms of thermal dissipation BGA is a worse election, but I want to know how much worse it is. I don't ...
1
vote
0
answers
42
views
MOSFET SOA: Isn't the package current limit-line ambient temperature dependent?
Ref 1 says "The package limit-line will not change in case application conditions such as ambient
temperature vary"
As explained in Ref2, this limit is due to bond wire heating/melting.
If ...
- 2,769
2
votes
0
answers
52
views
Estimating junction temperature
I made a measurement using thermocouple to measure the case temperature of my TO-220 linear regulator (L7809). I'll be using degrees celsius for all temperature units and degree Celsius/Watt for all ...
- 401
1
vote
3
answers
57
views
Is thermal impedance defined similar to electrical impedance?
Wiki: "Impedance defined in terms of jω can strictly be applied only to circuits that are driven with a steady-state AC signal"
I guess the thermal impedance is also defined similarly. ...
- 2,769
0
votes
0
answers
25
views
Battery charger failure
I'm using this Battery Charger IC - MCP73831.
I am using a SOT-23 package.
My input is 5V, the output Vbat charge regulated voltage on the Vbat pin is 4.2V and the maximum charge current is 340mA.
So, ...
- 1
14
votes
8
answers
4k
views
How much of the power drawn by a chip turns into heat?
If I have a circuit with a computing chip drawing 1W, how much of that gets turned into heat?
EDIT: I mean turned into heat 1. straight away (not in 1000 years) and 2. within the vicinity of the ...
- 249
1
vote
2
answers
77
views
What's the best approach to measuring an SMD component's temperature (using an SMD temperature sensor)
Question
Is there a temperature sensor (or else) which allows for the measurement of a copper pour on a PCB (and therefor the approximate temperature of a component)?
I want to read the temperature ...
- 868
13
votes
1
answer
1k
views
Why is my op-amp getting hot?
I am using a LM4562 dual op-amp (in SOIC-8) as a level-shift and attenuation stage between an audio amplifier and an ADC. The circuit works fine, with the expected gain and shift, but the op-amp gets ...
- 155
0
votes
1
answer
90
views
Using BS270 MOSFET as Temperature Sensor
I have previously asked a question about using thermocouples to maintain a temperature range of 36-39° inside an insulated and dry environment.
The more enlightened engineers advised I look into using ...
- 353
0
votes
0
answers
83
views
Pixel offset in image from FLIR Lepton 3.5 VoSPI
I´m working on my driver for a FLIR Lepton 3.5 thermal imaging sensor attached to an ESP32-S3I want to display the image on an LCD, but the image contains line offsets.
I use the following settings ...
- 422
0
votes
2
answers
120
views
Thermal issues: surface mounted on 1" x 1" FR4 board
A number of parts are rated at certain thermal impedance with a note, something along the lines of
surface mounted on 1" x 1" FR4 board
like in this datasheet for instance - MOSFET Vishay ...
- 1,060
2
votes
2
answers
209
views
I need to make a makeshift thermocouple given limited resources in the third world
I'm living in a part of the world where scrap electronics are hard to come by. Recycling these are big money in the impoverished SEA region I'm living in.
I have a Fluke 289 with a type K thermocouple ...
- 353
3
votes
1
answer
50
views
Maximum power of a TVS
I am trying to understand how much power a SMDJ58CA TVS can handle during a very short moment (~ 20 µs.)
The information into the datasheet are the following:
The peak pulse power rating @ 25°C for a ...
- 2,924
0
votes
2
answers
85
views
Is my heat sink properly sized for my LED strip?
I am looking for some help in sizing a heat sink for an LED horticulture light I am building. I will be attaching two Bridgelux BXEB-L1190U-30G3000-C-C3 LED strips side by side, link below to specs, ...
- 1
0
votes
1
answer
113
views
How to compensate for shunt resistor thermal drift? [closed]
I'm working on a electronic load and below schematic is the simplified version of it.
simulate this circuit – Schematic created using CircuitLab
The problem is the thermal drift in resistors ...
- 2,291
3
votes
2
answers
382
views
Do I need a bleeder resistor for discharging an inductor?
Pretty straightforward question, I'd say.
I know that for a capacitor I'd definitely want a bleeding/discharge resistor, and I know how to size one for that (cheat sheet for anyone curious), but what ...
- 319
0
votes
2
answers
87
views
Maximum Ambient temperature
In this IC, on page 35, the maximum operating temperature is given as 70degC or 85degC.
Is the datasheet maximum temperature value of 85C applicable to the surrounding medium? I ask because air will ...
user220456
0
votes
1
answer
114
views
Thermally insulating peltier cell [closed]
I'm trying to build a small cloud chamber using peltier cells. I've been using a TEC2 25408 and a cooler master 412S. So far I've tried to measure the lowest temperature the peltier can reach by ...
- 309
1
vote
1
answer
184
views
TP4056 / thermal pad
I am preparing a circuit using a TP4056. This circuit has a thermal pad. The datasheet says that this pad must be connected to ground or nothing.
However, some forum discussions talk about connecting ...
- 31
0
votes
0
answers
62
views
Thermal management of high power MOSFETS
I am intending to build a PWM solar battery charger with 80-160A, for which I have already asked another more general question. Most of the possible candidates for the output MOSFET look a little ...
- 773
2
votes
1
answer
28
views
Is this way of maximum current calculation correct for this voltage regulator?
Regarding using the LD39050PU33R voltage regulator which is 5V to 3.3V fixed voltage regulator without any heatsink, its maximum current is given as 500mA. I was trying to figure out how they ...
- 2,061
0
votes
0
answers
14
views
Thermal shutdown in HMC510, HMC507 and ADF4159
We have following chip combination cards:-
ADF4159CCPZ-RL7 and HMC507LP5ETR
ADF4159CCPZ-RL7 and HMC510LP5E
We have both PLL and VCO are on a single board. We are using same board for above combination....
- 217
0
votes
1
answer
28
views
Can HSG + TIM + HSG sandwich ever be better than one layer of HSG?
Here is a photo of a big diode and it's TIM (thermal interface material.) The foil appears to be aluminum, very thin and reflective, with white, crusty HSG (heatsink grease / paste / compound) on ...
- 16.1k