LT8391A 60V 2MHz Synchronous 4-Switch Buck-Boost LED Driver Controller FEATURES DESCRIPTION n 4-Switch Single Inductor Architecture Allows V The LT 8391A is a synchronous 4-switch buck-boost IN Above, Below or Equal to V LED controller that regulates LED current from input OUT n Up to 95% Efficiency at 2MHz voltage above, below, or equal to the output voltage. The n Proprietary Peak-Buck Peak-Boost Current Mode proprietary peak-buck peak-boost current mode control n Wide V Range: 4V to 60V scheme allows adjustable and synchronizable 600kHz to IN n Wide V Range: 0V to 60V (51V LED) 2MHz fixed frequency operation, or internal 25% triangle OUT n 3% LED Current Accuracy spread spectrum operation for low EMI. With 4V to 60V n 2000:1 External and 128:1 Internal PWM Dimming input, 0V to 60V output, and seamless low noise transi- n High Side PMOS PWM Switch Driver tions between operation regions, the LT8391A is ideal for n No Top MOSFET Refresh Noise in Buck or Boost LED driver and battery charger applications in automotive, n Adjustable and Synchronizable: 600kHz to 2MHz industrial, and battery-powered systems. n Flicker-Free Spread Spectrum for Low EMI The LT8391A provides both internal (up to 128:1) and n Open and Short LED Protection with Fault Reporting external (up to 2000:1) LED current PWM dimming with n Available in 28-Lead TSSOP with Exposed Pad and a high-side PMOS switch. Two CTRL pins provide flexible 28-Lead QFN (4mm 5mm) 20:1 analog dimming with 3% LED current accuracy at 100mV full scale. Fault protection is provided to detect an APPLICATIONS open or short LED condition, during which the LT8391A retries, latches off, or keeps running. n Automotive Head Lamps/Running Lamps L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Analog n High Frequency LED Lighting Devices, Inc. All other trademarks are the property of their respective owners. TYPICAL APPLICATION 94% Efficient 24W (16V, 1.5A) 2MHz Buck-Boost LED Driver 2.2H V 6m IN 6V TO 32V CONTINUOUS 4V TO 56V TRANSIENT 10F 4.7F 0.1F 0.1F 22F SW1 LSP LSN SW2 100V 25V 63V 2 BST1 BST2 2 Efficiency vs V IN 100 INTV INTV CC CC BG1 BG2 95 GND 90 TG1 TG2 V LT8391A V IN OUT 85 1F 1F 383k 1M 48.7k 80 EN/UVLO FB SSFM OFF 165k 75 ISP SYNC/SPRD SSFM ON INTV CC 56m 70 INTV CC ISN 4.7F 100k 65 PWMTG FAULT FAULT 60 ANALOG DIM CTRL1 PWM PWM DIM 0 5 10 15 20 25 30 35 40 45 100k INPUT VOLTAGE (V) V REF 8391a TA01b 0.47F 90.9k 16V PWM SETTING CTRL2 RP 1.5A LEDs 113k SS V RT C EXT INT 59.0k 4.7k 22nF 2MHz 300k 3.3nF 488Hz 8391a TA01a 8391af 1 For more information www.linear.com/LT8391A EFFICIENCY (%)LT8391A 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 LT8391AE .......................................... 40C to 125C BST1, BST2 ...............................................................66V LT8391AI ........................................... 40C to 125C SW1, SW2, LSP, LSN .................................... 6V to 60V LT8391AH .......................................... 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 BG1 1 28 BG2 2 BST2 BST1 27 28 27 26 25 24 23 SW1 3 26 SW2 TG1 1 22 TG2 4 TG2 TG1 25 LSP 2 21 V LSP 5 24 V OUT OUT 6 23 PWMTG LSN 3 20 PWMTG LSN V 7 22 SYNC/SPRD V 4 29 19 29 SYNC/SPRD IN IN GND GND 8 21 RT INTV 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 (