LTC3789 High Efficiency, Synchronous, 4-Switch Buck-Boost Controller FeaTuresDescripTion n Single Inductor Architecture Allows VIN Above, The LTC®3789 is a high performance buck-boost switch- Below or Equal to the Regulated VOUT ing regulator controller that operates from input volt- n Programmable Input or Output Current ages above, below or equal to the output voltage. The n Wide VIN Range: 4V to 38V constant-frequency, current mode architecture allows n 1% Output Voltage Accuracy: 0.8V < VOUT < 38V a phase-lockable frequency of up to 600kHz, while an n Synchronous Rectification: Up to 98% Efficiency output current feedback loop provides support for battery n Current Mode Control charging. With a wide 4V to 38V (40V maximum) input and n Phase-Lockable Fixed Frequency: 200kHz to 600kHz output range and seamless, low noise transitions between n No Reverse Current During Start-Up operating regions, the LTC3789 is ideal for automotive, n Power Good Output Voltage Monitor telecom and battery-powered systems. n Internal 5.5V LDO The operating mode of the controller is determined through n Quad N-Channel MOSFET Synchronous Drive the MODE/PLLIN pin. The MODE/PLLIN pin can select n VOUT Disconnected from VIN During Shutdown between pulse-skipping mode and forced continuous n True Soft-Start and VOUT Short Protection, Even in mode operation and allows the IC to be synchronized to an Boost Mode external clock. Pulse-skipping mode offers high efficiency n Available in 28-Lead QFN (4mm × 5mm) and and low ripple at light loads, while forced continuous 28-Lead SSOP Packages mode operates at a constant frequency for noise-sensitive applicaTions applications. n A PGOOD pin indicates when the output is within 10% of Automotive Systems n its designed set point. The LTC3789 is available in low pro- Distributed DC Power Systems n file 28-pin 4mm × 5mm QFN and narrow SSOP packages. High Power Battery-Operated Devices n Industrial Control L, LT, LTC, LTM, Linear Technology, the Linear logo, µModule and Burst Mode are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5408150, 5481178, 5929620, 6580258, 7365525, 7394231. Typical applicaTion + 1µF 4.7µF CER 100Ω Efficiency and Power Loss I – LIM INTVCC IOSENSE 2.2µF 100Ω V PGOOD I + IN OSENSE 0.010Ω VOUT 100 12 4V TO VIN EXTVCC 12V 38V VINSNS VOUTSNS 5A 10µF 22µF + 95 10 16V 330µF 50V A TG1 TG2 D 16V CER 0.1µF CER LTC3789 0.1µF POWER LOSS (W) BOOST1 BOOST2 90 8 SW1 SW2 B BG1 BG2 C 85 6 ITH MODE/PLLIN 2200pF SS RUN ON/OFF EFFICIENCY (%) 105k, 1% 80 4 8k VFB 1000pF 0.01µF FREQ SGND 7.5k 75 2 121k 1% VOUT = 12V SENSE+ SENSE– PGND ILOAD = 5A 70 0 0 5 10 15 20 25 30 35 40 0.010Ω VIN (V) 3789 TA01b 4.7µH 3789 TA01 3789fc For more information www.linear.com/LTC3789 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration order information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Typical Application Related Parts