Datasheet LTC3899 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 60V Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller with PassThru |
| Pages / Page | 38 / 1 — FEATURES. DESCRIPTION. Dual Buck Plus Single Boost Synchronous … |
| File Format / Size | PDF / 937 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Dual Buck Plus Single Boost Synchronous Controllers. Wide Bias Input Voltage Range: 4.5V to 60V
Model Line for this Datasheet
Text Version of Document
LTC3899 60V Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller
FEATURES DESCRIPTION
n
Dual Buck Plus Single Boost Synchronous Controllers
The LTC®3899 is a high performance triple output (buck/ n
Wide Bias Input Voltage Range: 4.5V to 60V
buck/boost) DC/DC switching regulator controller that n
Outputs Remain in Regulation Through Cold Crank
drives all N-channel synchronous power MOSFET stages.
Down to a 2.2V Input Supply Voltage
The constant frequency current mode architecture allows n
Buck and Boost Output Voltages Up to 60V
a phase-lockable frequency of up to 850kHz. The LTC3899 n
Adjustable Gate Drive Level 5V to 10V (OPTI-DRIVE)
operates from a wide 4.5V to 60V input supply range. n
No External Bootstrap Diodes Required
When biased from the output of the boost converter or n
Low Operating IQ: 29μA (One Channel On)
another auxiliary supply, the LTC3899 can operate from n
100% Duty Cycle for Boost Synchronous MOSFET
an input supply as low as 2.2V after start-up. n Phase-Lockable Frequency (75kHz to 850kHz) The gate drive for the LTC3899 can be programmed from n Programmable Fixed Frequency (50kHz to 900kHz) 5V to 10V to allow the use of logic-level or standard-level n Very Low Dropout Operation: 99% Duty Cycle (Bucks) FETs and to maximize efficiency. Internal switches in the n Low Shutdown IQ: 3.6μA top gate drivers eliminate the need for external bootstrap n Fixed or Adjustable Boost Output Voltage Saves IQ diodes. The 29μA no-load quiescent current extends op- n Small 38-Lead 5mm × 7mm QFN and TSSOP Packages erating run time in battery-powered systems. OPTI-LOOP® compensation allows the transient response to be optimized
APPLICATIONS
over a wide range of output capacitance and ESR values. n Automotive Always-On and Start-Stop Systems L, LT, LTC, LTM, Burst Mode, OPTI-LOOP, Linear Technology and the Linear logo are n Distributed DC Power Systems registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, n Multioutput Buck-Boost Applications 6144194, 6177787, 6580258.
TYPICAL APPLICATION High Efficiency Wide Input Range Dual 5V/8.5V Converter Efficiency vs Output Current
VOUT3 95 REGULATED AT 10V 33µF VIN = 12V WHEN VIN < 10V RUN1, 2, 3 VBIAS VOUT = 5V FOLLOWS VIN WHEN 94 V TG1 FB3 Burst Mode OPERATION VIN > 10V 0.1µF TG3 BOOST1 0.1µF 4.9µH 9mΩ V 93 OUT1 SW1 5V 3mΩ 1.2µH BOOST3 5A VIN BG1 92 SW3 2.2V TO 60V LTC3899 (START-UP 33µF BG3 ABOVE 5V) SENSE1+ 91 SENSE1– 357k EFFICIENCY (%) SENSE3– VFB1 GATE DRIVE (DRVCC) SENSE3+ 90 68.1k 220µF 5V DRVCC 6V INTVCC 89 8V 4.7µF 0.1µF 10V TG2 0.1µF 880.01 0.1 1 10 ITH1,2,3 BOOST2 6.5µH 15mΩ VOUT2 OUTPUT CURRENT(A) SW2 8.5V 3899 TA01b 3A BG2 DRVSET SENSE2+ SENSE2– 649k VPRG3 VFB2 GND 68.1k 68µF 3899 TA01a 3899fa For more information www.linear.com/LTC3899 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagrams Operation Typical Applications Package Description Typical Application Related Parts
FEATURES DESCRIPTION
n
Dual Buck Plus Single Boost Synchronous Controllers
The LTC®3899 is a high performance triple output (buck/ n
Wide Bias Input Voltage Range: 4.5V to 60V
buck/boost) DC/DC switching regulator controller that n
Outputs Remain in Regulation Through Cold Crank
drives all N-channel synchronous power MOSFET stages.
Down to a 2.2V Input Supply Voltage
The constant frequency current mode architecture allows n
Buck and Boost Output Voltages Up to 60V
a phase-lockable frequency of up to 850kHz. The LTC3899 n
Adjustable Gate Drive Level 5V to 10V (OPTI-DRIVE)
operates from a wide 4.5V to 60V input supply range. n
No External Bootstrap Diodes Required
When biased from the output of the boost converter or n
Low Operating IQ: 29μA (One Channel On)
another auxiliary supply, the LTC3899 can operate from n
100% Duty Cycle for Boost Synchronous MOSFET
an input supply as low as 2.2V after start-up. n Phase-Lockable Frequency (75kHz to 850kHz) The gate drive for the LTC3899 can be programmed from n Programmable Fixed Frequency (50kHz to 900kHz) 5V to 10V to allow the use of logic-level or standard-level n Very Low Dropout Operation: 99% Duty Cycle (Bucks) FETs and to maximize efficiency. Internal switches in the n Low Shutdown IQ: 3.6μA top gate drivers eliminate the need for external bootstrap n Fixed or Adjustable Boost Output Voltage Saves IQ diodes. The 29μA no-load quiescent current extends op- n Small 38-Lead 5mm × 7mm QFN and TSSOP Packages erating run time in battery-powered systems. OPTI-LOOP® compensation allows the transient response to be optimized
APPLICATIONS
over a wide range of output capacitance and ESR values. n Automotive Always-On and Start-Stop Systems L, LT, LTC, LTM, Burst Mode, OPTI-LOOP, Linear Technology and the Linear logo are n Distributed DC Power Systems registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, n Multioutput Buck-Boost Applications 6144194, 6177787, 6580258.
TYPICAL APPLICATION High Efficiency Wide Input Range Dual 5V/8.5V Converter Efficiency vs Output Current
VOUT3 95 REGULATED AT 10V 33µF VIN = 12V WHEN VIN < 10V RUN1, 2, 3 VBIAS VOUT = 5V FOLLOWS VIN WHEN 94 V TG1 FB3 Burst Mode OPERATION VIN > 10V 0.1µF TG3 BOOST1 0.1µF 4.9µH 9mΩ V 93 OUT1 SW1 5V 3mΩ 1.2µH BOOST3 5A VIN BG1 92 SW3 2.2V TO 60V LTC3899 (START-UP 33µF BG3 ABOVE 5V) SENSE1+ 91 SENSE1– 357k EFFICIENCY (%) SENSE3– VFB1 GATE DRIVE (DRVCC) SENSE3+ 90 68.1k 220µF 5V DRVCC 6V INTVCC 89 8V 4.7µF 0.1µF 10V TG2 0.1µF 880.01 0.1 1 10 ITH1,2,3 BOOST2 6.5µH 15mΩ VOUT2 OUTPUT CURRENT(A) SW2 8.5V 3899 TA01b 3A BG2 DRVSET SENSE2+ SENSE2– 649k VPRG3 VFB2 GND 68.1k 68µF 3899 TA01a 3899fa For more information www.linear.com/LTC3899 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagrams Operation Typical Applications Package Description Typical Application Related Parts
