LT8391 60V Synchronous 4-Switch Buck-Boost LED Controller with Spread Spectrum FEATURES DESCRIPTION n 4-Switch Single Inductor Architecture Allows V The LT 8391 is a synchronous 4-switch buck-boost LED IN Above, Below or Equal to V controller that regulates LED current from input voltage OUT n Synchronous Switching: Up to 98% Efciency above, below or equal to the output voltage. The propri- n Proprietary Peak-Buck Peak-Boost Current Mode etary peak-buck peak-boost current mode control scheme n Wide V Range: 4V to 60V allows adjustable and synchronizable 150kHz to 650kHz IN n Wide V Range: 0V to 60V (51V LED) fixed frequency operation, or internal 15% triangle spread OUT n 3% LED Current Accuracy spectrum operation for low EMI. With 4V to 60V input, 0V n 2000:1 External and 128:1 Internal PWM Dimming to 60V output, and seamless low noise transitions between n High Side PMOS PWM Switch Driver operation regions, the LT8391 is ideal for LED driver and n Integrated Bootstrap Diodes battery charger applications in automotive, industrial and n No Top MOSFET Refresh Noise in Buck or Boost battery-powered systems. n Adjustable and Synchronizable: 150kHz to 650kHz The LT8391 provides both internal (up to 128:1) and n Flicker-Free Spread Spectrum for Low EMI external (up to 2000:1) LED current PWM dimming with n Open and Short LED Protection with Fault Reporting a high side PMOS switch. Two CTRL pins provide flexible n Available in 28-Lead TSSOP with Exposed Pad and 20:1 analog dimming with 3% LED current accuracy at 28-Lead QFN (4mm 5mm) 100mV full scale. Fault protection is provided to detect an open or short LED condition, during which the LT8391 APPLICATIONS retries, latches off, or keeps running. n Automotive Head Lamps/Running Lamps All registered trademarks and trademarks are the property of their respective owners. n High Power LED Lighting TYPICAL APPLICATION 98% Efficient 50W (25V, 2A) Buck-Boost LED Driver Efficiency vs V IN 100 V IN 4.7F 10F 6V TO 55V 98 BOOST 33F 100V 50V BUCK 63V 1M 96 x2 x2 499k V IN 94 EN/UVLO BST1 BUCK-BOOST INTV CC 0.05 92 221k 34.8k TG1 0.1F 0.1F 4.7F 100k 90 SW1 88 10H FAULT FAULT 0.004 LSP V LSN 86 REF LT8391 0.47F 84 CTRL2 BG1 100k 82 GND ANALOG DIM CTRL1 5.1 80 25V PWM DIM PWM BG2 0 10 20 30 40 50 60 2A RP SW2 INPUT VOLTAGE (V) LED SYNC/SPRD TG2 RT 8391 TA01b BST2 V C FB SS V OUT 100k 2.2k ISP 400kHz 0.1F ISN 10nF PWMTG 8391 TA01a 8391fa 1 For more information www.linear.com/LT8391 EFFICIENCY (%)LT8391 ABSOLUTE MAXIMUM RATINGS (Note 1) V , EN/UVLO, V , ISP, ISN ...................................60V Operating Junction Temperature Range (Notes 2, 3) IN OUT (ISP-ISN) .........................................................1V to 1V LT8391E ............................................. 40C to 125C BST1, BST2 ...............................................................66V LT8391I .............................................. 40C to 125C SW1, SW2, LSP, LSN .................................... 6V to 60V LT8391H ............................................ 40C to 150C INTV , (BST1-SW1), (BST2-SW2) .............................6V Storage Temperature Range .................. 65C to 150C CC (BST1-LSP), (BST1-LSN) ............................................6V FB, PWM, SYNC/SPRD, CTRL1, CTRL2, FAULT ...........6V PIN CONFIGURATION TOP VIEW TOP VIEW 1 28 BG2 BG1 BST1 2 27 BST2 28 27 26 25 24 23 3 26 SW2 SW1 TG1 1 22 TG2 4 TG2 TG1 25 LSP 2 21 V LSP 5 24 V OUT OUT 6 PWMTG LSN LSN 23 3 20 PWMTG V 7 22 SYNC/SPRD 29 29 V 4 19 SYNC/SPRD IN IN GND GND 8 RT INTV 21 CC INTV 5 18 RT CC EN/UVLO 9 20 V C EN/UVLO 6 17 V C 10 19 FB RP RP 7 16 FB PWM 11 18 SS PWM 8 15 SS 12 17 FAULT V REF 9 10 11 12 13 14 CTRL1 13 16 CTRL2 14 15 ISN ISP FE PACKAGE UFD PACKAGE 28-LEAD PLASTIC TSSOP 28-LEAD (4mm 5mm) PLASTIC QFN = 30C/W, = 5C/W JA JC = 34C/W, = 3.4C/W JA JC EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION (