tag:blogger.com,1999:blog-2257458838727315711.post7693300044284954231..comments2024-03-21T00:37:26.331-07:00Comments on K6JCA: Counterfeit LM2596 Regulator BoardsJeffhttp://www.blogger.com/profile/04853314106806116765noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-2257458838727315711.post-49870867980014110352023-02-11T15:19:06.768-08:002023-02-11T15:19:06.768-08:00Hi,
Regarding ESR, please note that the tantalum ...Hi,<br /><br />Regarding ESR, please note that the tantalum cap that was used by Dick Benson in the post, above, was not a surface mount device.<br /><br />For an appropriate surface mount device you will need to sort through the ESR specifications of available surface-mount tantalum capacitors. Digikey might be a good site for this search.<br /><br />You will need to ensure that whatever package you use, its pins are compatible with the pads on the PCB.<br /><br />- Jeff<br />Jeffhttps://www.blogger.com/profile/04853314106806116765noreply@blogger.comtag:blogger.com,1999:blog-2257458838727315711.post-2227909229743913802023-02-11T05:45:40.195-08:002023-02-11T05:45:40.195-08:00
Sir, I would leave the fake chip(lm576) and chang...<br />Sir, I would leave the fake chip(lm576) and change the capacitor with Tantalum for decrease ripple, ESR value should and capacity should be like last table posted or can be even different? Wich size in mm should be for solder on the board?<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2257458838727315711.post-13885074394431121972019-12-28T14:30:52.209-08:002019-12-28T14:30:52.209-08:00Thanks for the comments.
I agree regarding input ...Thanks for the comments.<br /><br />I agree regarding input noise -- the input has the large current transients and therefore needs good low-ESR capacitance to mitigate the effects of those current transients.<br /><br />The triangular ripple voltage on the output is a direct function of the inductor's triangular current waveform (itself an integration of the constant voltage across the inductor, i.e. di = (V/L)dt).<br /><br />The triangular AC component of the inductor's current passes through the output capacitor (in parallel with the load), and thus the larger the value of the output capacitance, and the lower the ESR, the smaller will be the triangular ripple on the output DC.<br /><br />Regarding the regulator's +/-4% regulation -- note that the venerable (and ubiquitous) LM7800 series has a +/-4% spec over its range of operation, which is not far off from the LM2596's spec of 5% over its range. So, in my opinion, not horrible, and still very useful in many applications.<br /><br />- JeffJeffhttps://www.blogger.com/profile/04853314106806116765noreply@blogger.comtag:blogger.com,1999:blog-2257458838727315711.post-39616866310142949692019-12-27T20:15:32.919-08:002019-12-27T20:15:32.919-08:00Input capacitors matter more with a buck converter...Input capacitors matter more with a buck converter's topology. All the noise is generated on the input side from switching. Use a large low ESR cap on the input side!<br /><br />Output capacitors have little effect on output noise because of the inductor being in series with the load, already removing a lot of switching noise.<br /><br />Also, LM2596 is only suitable as a pre-regulator, as its +/-4% voltage regulation under ideal conditions, is horrible for most purposes. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2257458838727315711.post-90367849893473797872019-09-04T14:38:32.693-07:002019-09-04T14:38:32.693-07:00Great write up! I got a 6-pack of these same boar...Great write up! I got a 6-pack of these same boards from Amazon and was immediately suspicious of the poor quality top marking on the LM2596. I was also curious if the caps would prove to be counterfeit as well. When I have a chance I want to decap or X-ray one of the fake parts to see what it looks like inside. This is a good example of "if something seems to good to be true," when they're selling the entire board for less than the 1K quantity price for that LM2596 Simple Switcher.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2257458838727315711.post-45237928642389126502018-09-13T12:35:11.043-07:002018-09-13T12:35:11.043-07:00I could be wrong but to have the same ripple outpu...I could be wrong but to have the same ripple output the correct coil for the fake chip should be 3 times larger than the one mounted in pairs with the original chip.<br />These unwary people took the TI / ONsemiconductor datasheet and copied the application scheme and then mounted the fake chip.Anonymoushttps://www.blogger.com/profile/15276423681670852677noreply@blogger.com