{"id":944,"date":"2026-09-13T20:35:32","date_gmt":"2026-09-13T19:35:32","guid":{"rendered":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/?p=944"},"modified":"2026-09-13T20:35:44","modified_gmt":"2026-09-13T19:35:44","slug":"mic5504-ldo-failing-with-433mhz-radio-transmitter","status":"publish","type":"post","link":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/mic5504-ldo-failing-with-433mhz-radio-transmitter\/","title":{"rendered":"MIC5504 LDO Failing with 433MHz Radio Transmitter"},"content":{"rendered":"<p>A very short one&#8230;<\/p>\n<p>I recently had problems with an ESP32 board resetting while developing a LoRa networked system using ebyte E22 modules. This was tracked down to a catastrophic drop &#8211; I mean a serious drop to &lt;2V for several ms &#8211; in the voltage supplied to the ESP32 and, after some investigation, this was tracked down to the MIC5504 being used to drop a 3.7V nominal Lithium battery down to 3.3V. Replacing the LDO with a RT908033G35 fixed things and showed a clean oscilloscope trace. This wasn&#8217;t selected specifically to solve the issue, but had become my LDO of choice based on dropout voltage and current rating. It does have a better PSSR than the MIC5504 but I don&#8217;t think that, by itself, explains the dramatic difference in behaviour, so presume there was some nasty RF pickup in the MIC5504.<\/p>\n<p>This happened with a completely separate transmitter nearby, with NO electrical connection. &#8211; ie it is not high frequency ripple (LDOs typically do not have good rejection at high freq), nor a transient.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A very short one&#8230; I recently had problems with an ESP32 board resetting while developing a LoRa networked system using&#8230;<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-944","post","type-post","status-publish","format-standard","hentry","category-uncategorized","post-archive"],"_links":{"self":[{"href":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/wp-json\/wp\/v2\/posts\/944","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/wp-json\/wp\/v2\/comments?post=944"}],"version-history":[{"count":1,"href":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/wp-json\/wp\/v2\/posts\/944\/revisions"}],"predecessor-version":[{"id":945,"href":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/wp-json\/wp\/v2\/posts\/944\/revisions\/945"}],"wp:attachment":[{"href":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/wp-json\/wp\/v2\/media?parent=944"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/wp-json\/wp\/v2\/categories?post=944"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hilltop-cottage.info\/blogs\/adam\/wp-json\/wp\/v2\/tags?post=944"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}