POWER LOSS (W) LTC3709 TM Fast 2-Phase, No R , SENSE Synchronous DC/DC Controller with Tracking/Sequencing FEATURES DESCRIPTIO PolyPhase Valley Current Mode Controller The LTC 3709 is a single output, dual phase, synchronous Synchronizable to an External Clock with PLL step-down switching regulator. The controller uses a Coincident or Ratiometric Tracking constant on-time, valley current control architecture to Sense Resistor Optional deliver very low duty cycles without requiring a sense 2% to 90% Duty Cycle at 200kHz resistor. Operating frequency is selected by an external t < 100ns resistor and is compensated for variations in input supply ON(MIN) True Remote Sensing Differential Amplifier voltage. An internal phase-lock loop allows the LTC3709 High Efficiency at Both Light and Heavy Loads to be synchronized to an external clock. Power Good Output Voltage Monitor A TRACK pin is provided for tracking or sequencing the 0.6V 1% Reference output voltage among several LTC3709 chips or an Adjustable Current Limit LTC3709 and other DC/DC regulators. Soft-start is ac- Programmable Soft-Start and Operating Frequency complished using an external timing capacitor. Output Overvoltage Protection Fault protection is provided by an output overvoltage com- Optional Short-Circuit Shutdown Timer parator and an optional short-circuit shutdown timer. The Available in 32-Lead (5mm 5mm) QFN and 36-Lead current limit level is user programmable. A wide supply SSOP Packages range allows voltages as high as 31V to step down as low U as 0.6V. APPLICATIO S , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. No R is a trademark of Linear Technology Corporation. Notebook Computers SENSE PolyPhase is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Power Supply for DSP, ASIC, Graphic Processors Protected by U.S. Patents including 5481178, 6476589, 6144194, 5847554, 6100678, 6304066, 6580258, 6674274, 6462525, 6593724. TYPICAL APPLICATIO High Efficiency Dual Phase 1.5V/30A Step-Down Converter 5V 4.7F 324k 10 V IN 4.5V TO 28V 10F 35V 1F V DRV I 47.5k 3 CC CC ON TRACK TG1 HAT2168H Efficiency and Power Loss V RNG 0.22F FCB BOOST1 100 10 1.22H 10k V = 12V IN 100k 95 9 SW1 + 0.1F PGOOD SENSE1 90 8 EFFICIENCY RUN/SS BG1 HAT2165H 85 7 EXTLPF 3.32k SENSE1 80 6 INTLPF PGND1 75 5 100nF I LTC3709 TH V IN 70 4 20k 680pF HAT2168H SGND TG2 65 3 0.22F POWER LOSS 10k BOOST2 60 2 1.22H V OUT V SW2 1.5V FB 55 1 + 30A DIFFOUT SENSE2 50 0 15k BG2 HAT2165H 0.01 0.1 1 10 100 + 330F V LOAD CURRENT (A) OS SENSE2 + 2.5V V 3709 TA01b OS PGND2 4 3709 TA01a 3709fb 1 EFFICIENCY (%) U ULTC3709 ABSOLUTE AXI U RATI GS (Note 1) Input Supply Voltage (V , DRV ) ............ 7V to 0.3V I Voltage ............................................... 2.7V to 0.3V CC CC TH Boosted Topside Driver Supply Voltage V Voltage .............................................. 2.7V to 0.3V FB (BOOST1, BOOST2) .................................. 37V to 0.3V INTLPF, EXTLPF Voltages ........................ 2.7V to 0.3V + Switch Voltage (SW1, 2) ............................. 31V to 1V V , V Voltages ................................... 7V to 0.3V OS OS + + SENSE1 , SENSE2 Voltages....................... 31V to 1V FCB Voltage ................................................ 7V to 0.3V SENSE1 , SENSE2 Voltages.................... 10V to 0.3V Operating Temperature Range (Note 4) .. 40C to 85C I Voltage ............................................... 31V to 0.3V Junction Temperature (Note 2)............................ 125C ON (BOOST SW) Voltages ..............................7V to 0.3V Storage Temperature Range RUN/SS, PGOOD Voltages .......................... 7V to 0.3V UH Package ..................................... 65C to 125C TRACK Voltage ............................................7V to 0.3V G Package ....................................... 65C to 150C V Voltage ................................. V + 0.3V to 0.3V RNG CC UUW PACKAGE/ORDER I FOR ATIO TOP VIEW 1 BOOST1 NC 36 TOP VIEW 2 TG1 PGOOD 25 3 SW1 I 34 ON + 4 SENSE1 FCB 33 32 31 30 29 28 27 26 25 5 SENSE1 V 32 RNG RUN/SS 1 24 SENSE1 6 PGND1 RUN/SS 31 I 2 23 PGND1 TH 7 BG1 I 30 TH V 3 22 BG1 FB 8 DRV V 29 FB CC TRACK 4 21 DRV CC 9 BG2 TRACK 28 33 SGND 5 20 BG2 10 PGND2 SGND 27 SGND 6 19 PGND2 11 SENSE2 SGND 26 V 7 18 SENSE2 OS 12 V V 25 OS CC DIFFOUT 8 17 V CC + 13 SENSE2 DIFFOUT 24 9 10 11 12 13 14 15 16 + 14 SW2 V 23 OS 15 TG2 EXTLPF 22 16 BOOST2 INTLPF 21 UH PACKAGE 17 NC NC 20 32-LEAD (5mm 5mm) PLASTIC QFN 18 NC NC 19 EXPOSED PAD IS SGND (PIN 33) MUST BE SOLDERED TO PCB G PACKAGE T = 125C, = 34C/ W JMAX JA 36-LEAD PLASTIC SSOP T = 125C, = 95C/ W JMAX JA ORDER PART NUMBER UH PART MARKING ORDER PART NUMBER LTC3709EG LTC3709EUH 3709 Order Options Tape and Reel: Add TR Lead Free: Add PBF Lead Free Tape and Reel: Add TRPBF Lead Free Part Marking: