Datasheet LTC3649 (Analog Devices)

LTC3649 60V, 4A Synchronous Step-Down Regulator with Rail-to-Rail Programmable Output
FEATURES DESCRIPTION
n
Wide VIN Range: 3.1V to 60V
The LTC®3649 is a high efficiency 60V, 4A synchronous n
Wide VOUT Range: 0V to (VIN – 0.5V)
monolithic step-down regulator. The regulator features n
Single Resistor VOUT Programming
a single resistor programmable output voltage, internal n
Integrated 110mΩ Top N-Channel/50mΩ Bottom
compensation and high efficiencies over a wide VOUT range.
N-Channel MOSFETs
The step-down regulator operates from an input voltage n
95% Efficiency with 12VIN and 5VOUT
range of 3.1V to 60V and provides an adjustable rail-to-rail n
Regulated IQ: 440µA, Shutdown IQ: 18µA
output range from (VIN – 0.5V) to ground while delivering n
Accurate Current Monitoring (±4%) without Sense
up to 4A of output current. The switching frequency is
Resistor
also adjusted with an external resistor. A user-selectable n
Accurate Resistor Programmable Frequency
mode input is provided to allow the user to trade off ripple
(300kHz to 3MHz) with ±50% Frequency Sync Range
noise for efficiency at light loads; Burst Mode operation n
Accurate Programmable Output Current
provides the highest efficiency at light loads, while forced n
Input Voltage Regulation for MPPT Applications
continuous mode provides low output ripple. The MODE/ n ±0.8% Output Voltage Accuracy SYNC pin can also be used to allow the user to synchronize n Peak Current Mode Operation the switching frequency to an external clock. n Programmable Wire Drop Compensation n Burst Mode® Operation, Forced Continuous Mode The LTC3649 operates with a peak current mode architec- n Internal Compensation and Programmable Soft-Start ture that allows for fast transient response with inherent n Overtemperature Protection cycle-to-cycle current limit protection. It also features n Available in Thermally Enhanced 28-Lead (4mm × programmable output current limit, current monitoring 5mm) QFN and TSSOP Packages and input voltage regulation. L, LT, LTC, LTM, Linear Technology, the Linear logo, Burst Mode and OPTI-LOOP are
APPLICATIONS
registered trademarks of Analog Devices, Inc. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 5705919, 5847554, 6580258. n Industrial Applications n Automotive Applications
TYPICAL APPLICATION Efficiency with VOUT = 5V 24V to 5VOUT Burst Mode Operation
100 V 0.1µF IN = 12V 98 VIN = 24V 96 V 6.8µH IN 94 5.5V TO 60V VIN BOOST SW VOUT RUN V 92 OUT 5V 22µF 47µF 4A LTC3649 90 EXTVCC ×2 88 ITH MODE/SYNC EFFICIENCY (%) VINREG SGND 86 INTVCC PGND 2.2µF 84 ISET RT IMON 82 100k 10nF 200k 10k 10nF 80 0 0.5 1 1.5 2 2.5 3 3.5 4 IOUT (A) f 3649 TA01a SW = 500kHz 3649 TA01b 3649fb For more information www.linear.com/LTC3649 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts