POWER LOSS (mW) LTC3562 2 I C Quad Synchronous Step-Down DC/DC Regulator 2 600mA, 2 400mA FEATURES DESCRIPTION 2 n Four Independent I C Controllable Step-Down The LTC 3562 is a quad high ef ciency monolithic syn- 2 Regulators (2 600mA, 2 400mA) chronous step-down regulator with an I C interface. Two 2 n Two I C Programmable Feedback Voltage regulators are externally adjustable and can have their Regulators (R600A, R400A): V 425mV to 800mV feedback voltages programmed between 425mV and FB 2 n Two I C Programmable Output Voltage Regulators 800mV in 25mV steps (Type A). The other two regulators (R600B, R400B): V 600mV to 3.775V are xed output regulators whose output voltages can be OUT n Programmable Modes: Pulse Skip, LDO, Burst Mode, programmed between 600mV and 3.775V in 25mV steps Forced Burst Mode Operation (Type B). All four regulators operate independently and n Quiescent Current < 100A (All Regulators Enabled can be put into pulse skip, LDO, Burst Mode operation, 2 in LDO Mode) or forced Burst Mode operation through I C control. The n Fixed 2.25MHz Switching Frequency (Pulse Skip Type-A regulators have separate RUN pins that can be 2 Mode) enabled if I C control is unavailable. n Slew Limiting Reduces Switching Noise The 2.85V to 5.5V input voltage range makes the LTC3562 n Power-On Reset Output for Regulator R600A ideally suited for single Li-Ion battery-powered applica- n Small, Thermally Enhanced, 20-Lead 3mm 3mm tions. At low output load conditions, the regulators can QFN Package be switched into LDO, Burst Mode operation, or forced Burst Mode operation, extending battery life in portable APPLICATIONS systems. The quiescent current drops to under 100A with all regulators in LDO mode, and under 0.1A when n Miscellaneous Handheld Applications with Multiple all regulators are shut down. Supply Rails n Personal Information Appliances Switching frequency is internally set to 2.25MHz, allowing n Wireless and DSL Modems the use of small surface mount inductors and capacitors. n Digital Still Cameras All regulators are internally compensated. The LTC3562 is n MP3 Players available in a low pro le 3mm 3mm QFN package. n Portable Instruments L, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION R600x Burst Mode Ef ciency 2 High Ef ciency Quad Step-Down Converter with I C and Power Loss vs Load Current MICROPROCESSOR 100 10000 V = 3.3V SDA OUT + Li-Ion/Polymer 90 SCL 3.4V TO 4.2V 10F DV V = OUT CC V = 1.2V 80 OUT 1000 2.5V POR V SCL SDA DV IN CC V 600A 100k OUT 70 V = OUT 1.8V V RUN400A OUT 1.8V 4.7 H 3.3H POR600A 600mA 60 100 400A SW400A SW600A 1.5V 50 LTC3562 10 F 10pF 10pF 10 F 400mA 475k FB600A 634k 40 10 FB400A RUN600A 30 499k 536k V = 1.2V, V = 3.3V OUT OUT 1.8V, 2.5V 20 1 4.7 H 3.3 H V 400B V 600B 10 OUT OUT SW400B SW600B V = 3.8V 1.2V 3.3V IN 0 0.1 400mA OUT400B PGND AGND OUT600B 600mA 10F 10 F 0.01 0.1 1 10 100 1000 3562 TA01 LOAD CURRENT (mA) 3562 TA01b 3562fa 1 EFFICIENCY (%)LTC3562 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 2) TOP VIEW V ...............................................................0.3V to 6V IN RUN600A ...................................... 0.3V to (V + 0.3V) IN RUN400A ...................................... 0.3V to (V + 0.3V) IN 20 19 18 17 16 FBx ...............................................................0.3V to 6V POR600A AGND 1 15 SWx .............................................................0.3V to 6V FB600A FB400A 2 14 OUTx ............................................................0.3V to 6V 21 OUT600B OUT400B 3 13 DV , POR600A, SDA, SCL .........................0.3V to 6V SW600B SW400B 4 12 CC PGND I (DC) ........................................................600mA PGND 5 11 SW400x 6 7 8 9 10 I (DC) ........................................................850mA SW600x Operating Temperature (Note 2)...............40C to 85C Storage Temperature Range ...................65C to 125C UD PACKAGE Junction Temperature (Note 3) ............................. 125C 20-LEAD (3mm 3mm) PLASTIC QFN T = 125C, = 68C/W JMAX JA EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3562EUD PBF LTC3562EUD TRPBF LCPV 20-Lead (3mm 3mm) Plastic QFN 40C to 85C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: