{"id":5435,"date":"2013-03-01T22:00:57","date_gmt":"2013-03-02T06:00:57","guid":{"rendered":"http:\/\/mightyohm.com\/blog\/?p=5435"},"modified":"2022-12-27T17:36:39","modified_gmt":"2022-12-28T01:36:39","slug":"bus-pirate-v4-oscillates-too-tantalum-cap-to-the-rescue","status":"publish","type":"post","link":"https:\/\/mightyohm.com\/blog\/2013\/03\/bus-pirate-v4-oscillates-too-tantalum-cap-to-the-rescue\/","title":{"rendered":"Bus Pirate v4 oscillates too. Tantalum cap to the rescue!"},"content":{"rendered":"

This week I finally received my Bus Pirate v4<\/a>\u00a0from Seeed Studio<\/a>.<\/p>\n

The first thing I did after opening the box was to probe the 3.3V rail with the BP internal power supply enabled.<\/p>\n

Here’s what I saw:<\/p>\n

\"Bus<\/a><\/p>\n

That looks familiar!<\/a> \u00a0Except this time it’s an oscillation at 5.9kHz and 400mVpp<\/strong>! \u00a0(almost 4 times what I saw on the SFE Bus Pirate).<\/p>\n

I replaced C11 with a 4.7uF tantalum surface mount cap that I scavenged from another board, and the oscillation went away completely:<\/p>\n

\"Bus<\/a><\/p>\n

 <\/p>\n

Ahh, that’s better!<\/p>\n

Again, I strongly suspect the low ESR of the ceramic cap is to blame. \u00a0The 3.3V regulator really needs to see the higher ESR of a tantalum or electrolytic cap for stability.<\/p>\n

My advice to all Bus Pirate owners is to check your 3.3V rail with a scope, if possible, and replace C11 with a tantalum or electrolytic cap. \u00a0Alternatively you may be able to add a small amount of resistance in series with the ceramic cap that comes with the Bus Pirate, but I haven’t verified this.<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

This week I finally received my Bus Pirate v4\u00a0from Seeed Studio. The first thing I did after opening the box was to probe the 3.3V rail with the BP internal power supply enabled. Here’s what I saw: That looks familiar! \u00a0Except this time it’s an oscillation at 5.9kHz and 400mVpp! \u00a0(almost 4 times what I … Continue reading Bus Pirate v4 oscillates too. Tantalum cap to the rescue!<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[5],"tags":[461,463,466,462,465,464,467],"class_list":["post-5435","post","type-post","status-publish","format-standard","hentry","category-electronics","tag-bus-pirate","tag-capacitor","tag-dangerous-prototypes","tag-oscillation","tag-seeed","tag-stability","tag-tantalum"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pioCd-1pF","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"jetpack-related-posts":[{"id":5416,"url":"https:\/\/mightyohm.com\/blog\/2013\/02\/simple-fix-for-bus-pirate-power-supply-oscillations\/","url_meta":{"origin":5435,"position":0},"title":"Simple fix for Bus Pirate power supply oscillations","author":"Jeff","date":"February 24, 2013","format":false,"excerpt":"I picked up this Sparkfun Bus Pirate a couple years ago (thanks to Free Day!) It sat in a box for most of its life until recently I needed a simple way to interface a PC to an I2C device at work. \u00a0Out came the Bus Pirate. I'm fortunate to\u2026","rel":"","context":"In "Electronics"","block_context":{"text":"Electronics","link":"https:\/\/mightyohm.com\/blog\/category\/electronics\/"},"img":{"alt_text":"Modified SFE Bus Pirate","src":"https:\/\/i0.wp.com\/mightyohm.com\/files\/flickr\/8488859660_48aaa14e2f.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":5807,"url":"https:\/\/mightyohm.com\/blog\/2015\/02\/cool-tools-adafruit-edition\/","url_meta":{"origin":5435,"position":1},"title":"Cool Tools: Adafruit Edition","author":"Jeff","date":"February 9, 2015","format":false,"excerpt":"SMT\/SMD Resistor and Capacitor Books This\u00a00805 SMD resistor and capacitor book\u00a0is just like the ones sold on eBay and just as useful. 0603's are here. Blank books and pages are here. 65 Piece Ratchet Screwdriver and Tool Bit Set This 65 piece ratcheting screwdriver set is a bit nicer than\u2026","rel":"","context":"In "Books and Resources"","block_context":{"text":"Books and Resources","link":"https:\/\/mightyohm.com\/blog\/category\/books-and-resources\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/mightyohm.com\/blog\/wp-content\/uploads\/2014\/12\/829-00.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/mightyohm.com\/blog\/wp-content\/uploads\/2014\/12\/829-00.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/mightyohm.com\/blog\/wp-content\/uploads\/2014\/12\/829-00.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/mightyohm.com\/blog\/wp-content\/uploads\/2014\/12\/829-00.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":266,"url":"https:\/\/mightyohm.com\/blog\/2008\/09\/yarrrrr\/","url_meta":{"origin":5435,"position":2},"title":"Yarrrrr!!!","author":"Jeff","date":"September 19, 2008","format":false,"excerpt":"Today be talk like a pirate day.","rel":"","context":"In \"pirates\"","block_context":{"text":"pirates","link":"https:\/\/mightyohm.com\/blog\/tag\/pirates\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":2493,"url":"https:\/\/mightyohm.com\/blog\/2009\/10\/improvements-to-my-microscope-setup-for-smt-work\/","url_meta":{"origin":5435,"position":3},"title":"Improvements to my microscope setup for SMT work","author":"Jeff","date":"October 26, 2009","format":false,"excerpt":"Why do I need a microscope for SMT? 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If the USPS ever opens this box for inspection, they will get a nice surprise... Lots of junk! This is what I took: A SAW voice recorder A Game Boy (with Dr. Mario!)\u2026","rel":"","context":"In "Electronics"","block_context":{"text":"Electronics","link":"https:\/\/mightyohm.com\/blog\/category\/electronics\/"},"img":{"alt_text":"TGIMBOEJ GRAY-R","src":"https:\/\/i0.wp.com\/mightyohm.com\/files\/flickr\/5261990962_4457043411.jpg?resize=350%2C200","width":350,"height":200},"classes":[]}],"_links":{"self":[{"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/posts\/5435","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/comments?post=5435"}],"version-history":[{"count":5,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/posts\/5435\/revisions"}],"predecessor-version":[{"id":15768,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/posts\/5435\/revisions\/15768"}],"wp:attachment":[{"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/media?parent=5435"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/categories?post=5435"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/tags?post=5435"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}