Datasheet LTC3866 (Analog Devices)

LTC3866 Current Mode Synchronous Controller for Sub Milliohm DCR Sensing
FeaTures DescripTion
n
Sub Milliohm DCR Current Sensing
The LTC®3866 is a single phase current mode synchronous n
High Efficiency: Up to 95%
step-down switching regulator controller that drives all n
Selectable Current Sensing Limit
N-channel power MOSFET switches. It employs a unique n
Programmable DCR Temperature Compensation
architecture which enhances the signal-to-noise ratio of n
Die Overtemperature Thermal Shutdown
the current sense signal, allowing the use of a very low n
± 0.5% 0.6V Output Voltage Accuracy
DC resistance power inductor to maximize the efficiency n
Programmable Fixed Frequency 250kHz to 770kHz
in high current applications. This feature also reduces the n
High Speed Differential Remote Sense Amplifier
switching jitter commonly found in low DCR applications. n Wide Input Voltage Range: 4.5V to 38V The LTC3866 also includes a high speed remote sense dif- n Output Voltage Range: 0.6V to 3.5V with Diffamp ferential amplifier, a programmable current sense limit that n Adjustable Soft-Start or Output Voltage Tracking can be selected to 10mV, 15mV, 20mV, 25mV or 30mV, n Foldback Output Current Limit and DCR temperature compensation to limit the maximum n Short-Circuit Soft Recovery output current precisely over temperature. n Output Overvoltage Protection The LTC3866 also features a precise 0.6V reference with a n 24-Lead (4mm × 4mm) QFN and 24-Lead FE Packages guaranteed limit of ±0.5% that provides an accurate output voltage from 0.6V to 3.5V. A 4.5V to 38V input voltage
applicaTions
range allows it to support a wide variety of bus voltages and various types of batteries. n Computer Systems n The LTC3866 is offered in a low profile 24-lead 4mm × Telecom Systems n 4mm QFN and 24-lead exposed pad FE packages. Industrial and Medical Instruments n DC Power Distribution Systems L, LT, LTC, LTM, Burst Mode, OPTI-LOOP, Linear Technology and the Linear logo are registered trademarks and No RSENSE is a trademark of Analog Devices, Inc. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 5705919, 5929620, 6177787, 6580258, 6498466, 6611131, patent pending.
Typical applicaTion High Efficiency, 1.5V/30A Step-Down Converter with Very Low DCR Sensing Efficiency vs Load Current
100k
and Mode
FREQ MODE/PLLIN VIN 4.5V TO 20V 0.1µF 100 RUN PGOOD 220µF TK/SS ITEMP 4.7µF 90 ITH EXTVCC 80 VFB LTC3866 VIN 70 DIFFOUT INTVCC 0.1µF 60 DIFFP BOOST 0.33µH 50 V 30.1k DIFFN TG IN = 12V DCR = 0.32mΩ VOUT 40 VOUT = 1.5V SNSD+ SW 1.5V EFFICIENCY (%) L = 0.33µH C1 30A 30 (DCR = 0.32mΩ TYP) 220pF 20k SNS– BG COUT 220nF 470µF R2 R1 CCM 10k SNSA+ PGND 20 PULSE SKIPPING C2 4.64k ×2 931Ω 1.5nF Burst Mode 220nF ILIM CLKOUT 10 SGND OPERATION 00.01 0.1 1 10 100 LOAD CURRENT (A) 3866 TA01b 3866 TA01a 3866fc For more information www.linear.com/LTC3866 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts