{"product_id":"uc3845-sop8-current-mode-pwm-controller-ic-50-duty-cycle","title":"UC3845 SOP-8 Current-Mode PWM Controller IC 50% Duty Cycle (5-Pack)","description":"\u003ch2\u003eUC3845 SOP-8 Current-Mode PWM Controller IC - 50% Max Duty Cycle (5-Pack)\u003c\/h2\u003e\u003cp\u003eThe \u003cstrong\u003eUC3845\u003c\/strong\u003e is a current-mode PWM controller in a \u003cstrong\u003eSOP-8\u003c\/strong\u003e surface-mount package, identical to the UC3842 but with a \u003cstrong\u003e50% maximum duty cycle clamp\u003c\/strong\u003e and lower UVLO thresholds (\u003cstrong\u003e8.5V on \/ 7.6V off\u003c\/strong\u003e). The 50% duty cycle limit makes it ideal for \u003cstrong\u003eforward converters\u003c\/strong\u003e where transformer volt-second balance must be maintained, and the lower UVLO suits lower-voltage auxiliary supply designs.\u003c\/p\u003e\u003ch3\u003eKey Specifications\u003c\/h3\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eParameter\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePart Number\u003c\/td\u003e\n\u003ctd\u003eUC3845\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePackage\u003c\/td\u003e\n\u003ctd\u003eSOP-8 (SMD)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTopology\u003c\/td\u003e\n\u003ctd\u003eCurrent-mode PWM (fixed frequency)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMax Duty Cycle\u003c\/td\u003e\n\u003ctd\u003e50% (internal clamp)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMax Oscillator Frequency\u003c\/td\u003e\n\u003ctd\u003e500kHz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGate Drive Output\u003c\/td\u003e\n\u003ctd\u003e1A peak (totem-pole)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUVLO Thresholds\u003c\/td\u003e\n\u003ctd\u003e8.5V on \/ 7.6V off\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eReference Voltage\u003c\/td\u003e\n\u003ctd\u003e5V (2% accuracy)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCurrent Sense Threshold\u003c\/td\u003e\n\u003ctd\u003e1V (cycle-by-cycle OCP)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temperature\u003c\/td\u003e\n\u003ctd\u003e0C to +70C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eQuantity\u003c\/td\u003e\n\u003ctd\u003e5 pieces\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch3\u003eUC384x Family - Choose the Right Part\u003c\/h3\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003ePart\u003c\/th\u003e\n\u003cth\u003eMax Duty Cycle\u003c\/th\u003e\n\u003cth\u003eUVLO On\/Off\u003c\/th\u003e\n\u003cth\u003ePackage\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUC3842\u003c\/td\u003e\n\u003ctd\u003e100%\u003c\/td\u003e\n\u003ctd\u003e16V \/ 10V\u003c\/td\u003e\n\u003ctd\u003eDIP-8 \/ SOP-8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUC3843\u003c\/td\u003e\n\u003ctd\u003e50%\u003c\/td\u003e\n\u003ctd\u003e8.5V \/ 7.6V\u003c\/td\u003e\n\u003ctd\u003eDIP-8 \/ SOP-8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUC3844\u003c\/td\u003e\n\u003ctd\u003e50%\u003c\/td\u003e\n\u003ctd\u003e16V \/ 10V\u003c\/td\u003e\n\u003ctd\u003eDIP-8 \/ SOP-8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUC3845\u003c\/td\u003e\n\u003ctd\u003e50%\u003c\/td\u003e\n\u003ctd\u003e8.5V \/ 7.6V\u003c\/td\u003e\n\u003ctd\u003eDIP-8 \/ SOP-8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch3\u003eWhy Choose UC3845?\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e50% Duty Cycle Clamp\u003c\/strong\u003e - Prevents transformer saturation in forward converter designs\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow UVLO (8.5V\/7.6V)\u003c\/strong\u003e - Starts up from lower auxiliary supply voltages vs UC3842\/3844\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCurrent-Mode Control\u003c\/strong\u003e - Inherent cycle-by-cycle OCP and improved transient response\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSOP-8 SMD Package\u003c\/strong\u003e - Compact footprint for modern SMPS PCB designs\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDrop-in for UC3843\u003c\/strong\u003e - Same pinout and function as UC3843 (SOP-8 version)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eTypical Applications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eSingle-ended forward converter SMPS\u003c\/li\u003e\n\u003cli\u003eDC-DC converter with 50% duty cycle limit\u003c\/li\u003e\n\u003cli\u003eFlyback converter (lower UVLO for auxiliary startup)\u003c\/li\u003e\n\u003cli\u003eSMPS repair replacement for UC3843\/UC3845\u003c\/li\u003e\n\u003cli\u003eIndustrial power supply controller\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eQ: Can UC3845 replace UC3843?\u003c\/strong\u003e Yes - UC3845 and UC3843 are electrically identical (same pinout, same UVLO, same 50% duty cycle). UC3845 is the SOP-8 SMD version; UC3843 is typically DIP-8.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eQ: Why use UC3845 instead of UC3842 for a forward converter?\u003c\/strong\u003e Forward converters require duty cycle below 50% to prevent transformer core saturation. UC3845 enforces this limit in hardware, preventing accidental saturation if the feedback loop fails.\u003c\/p\u003e\u003ch3\u003ePackage Contents\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e5x UC3845 SOP-8 Current-Mode PWM Controller IC\u003c\/li\u003e\u003c\/ul\u003e","brand":"Keszoox","offers":[{"title":"Default Title","offer_id":46991506473195,"sku":"\u003cnone\u003e","price":6.04,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/1005\/8731\/files\/uc3845-sop8-pwm-controller-smd-ic-chipset.webp?v=1761529899","url":"https:\/\/keszoox.com\/products\/uc3845-sop8-current-mode-pwm-controller-ic-50-duty-cycle","provider":"Keszoox","version":"1.0","type":"link"}