{"id":790,"date":"2012-03-06T13:26:04","date_gmt":"2012-03-06T12:26:04","guid":{"rendered":"http:\/\/www.sciencetronics.com\/greenphotons\/?p=790"},"modified":"2025-06-16T18:38:19","modified_gmt":"2025-06-16T16:38:19","slug":"be-careful-with-manufacturers","status":"publish","type":"post","link":"https:\/\/www.sciencetronics.com\/greenphotons\/?p=790","title":{"rendered":"Be careful with manufacturers"},"content":{"rendered":"<p>I just wanted to construct a simple constant-current source using a shunt regulator. The shunt regulator TS431 &#8211; which I had lying around &#8211; is made by both <a href=\"http:\/\/www.st.com\/internet\/com\/TECHNICAL_RESOURCES\/TECHNICAL_LITERATURE\/DATASHEET\/CD00001336.pdf\" target=\"_blank\">ST<\/a> and by <a href=\"http:\/\/www.ts.com.tw\/db\/pictures\/modules\/PDT\/PDT060207001\/TS431_F07.pdf\" target=\"_blank\">Taiwan Semiconductor<\/a>. <\/p>\n<p>Both manufacturers use the same component name, the same package and the same description. However, there is one significant difference: while the ST part has an internal reference voltage of 1.2&nbsp;V (possibly derived from a bandgap reference) the Taiwanese counterpart has an internal reference voltage of 2.5&nbsp;V (possibly derived from a Zener junction).<\/p>\n<p>Why is this important? Look at the schematic of a constant-current source below:<br \/>\n<a href=\"http:\/\/www.sciencetronics.com\/greenphotons\/wp-content\/uploads\/2012\/03\/20120306_ts431_cc.png\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/www.sciencetronics.com\/greenphotons\/wp-content\/uploads\/2012\/03\/20120306_ts431_cc-300x133.png\" alt=\"\" title=\"20120306_ts431_cc\" width=\"300\" height=\"133\" class=\"aligncenter size-medium wp-image-791\" srcset=\"https:\/\/www.sciencetronics.com\/greenphotons\/wp-content\/uploads\/2012\/03\/20120306_ts431_cc-300x133.png 300w, https:\/\/www.sciencetronics.com\/greenphotons\/wp-content\/uploads\/2012\/03\/20120306_ts431_cc-150x66.png 150w, https:\/\/www.sciencetronics.com\/greenphotons\/wp-content\/uploads\/2012\/03\/20120306_ts431_cc-400x177.png 400w, https:\/\/www.sciencetronics.com\/greenphotons\/wp-content\/uploads\/2012\/03\/20120306_ts431_cc.png 606w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p>The current through the load, <em>I<sub>L<\/sub><\/em>, is determined by the ratio <em>I<sub>L<\/sub>=V<sub>ref<\/sub>\/R<sub>CL<\/sub><\/em>. Having different reference voltages gives you significantly different currents. And the same is true for every other possible circuit using this component.<\/p>\n<p>This is the first time that I see the <em>same<\/em> component made by different manufacturers with such different characteristics. And this is not even the question of counterfeit components, these are two official manufacturers!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I just wanted to construct a simple constant-current source using a shunt regulator. The shunt regulator TS431 &#8211; which I had lying around &#8211; is made by both ST and by Taiwan Semiconductor. Both manufacturers use the same component name, the same package and the same description. However, there is one significant difference: while the [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":791,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_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":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"enabled":false},"version":2}},"categories":[11,8],"tags":[],"class_list":["post-790","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-electronics_en","category-everything_en","entry","has-media"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/www.sciencetronics.com\/greenphotons\/wp-content\/uploads\/2012\/03\/20120306_ts431_cc.png","jetpack_shortlink":"https:\/\/wp.me\/p48grL-cK","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=\/wp\/v2\/posts\/790","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=790"}],"version-history":[{"count":4,"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=\/wp\/v2\/posts\/790\/revisions"}],"predecessor-version":[{"id":2497,"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=\/wp\/v2\/posts\/790\/revisions\/2497"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=\/wp\/v2\/media\/791"}],"wp:attachment":[{"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=790"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=790"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.sciencetronics.com\/greenphotons\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=790"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}