Datasheet LT3840 (Analog Devices)

LT3840 Wide Input Range Synchronous Regulator Controller with Accurate Current Limit
FeaTures DescripTion
n
Wide Input Range: 2.5V to 60V
The LT®3840 is a high voltage synchronous step-down n
Integrated Buck-Boost Supply for 7.5V MOSFET
switching regulator controller capable of operating from
Gate Drive
a 2.5V to 60V supply. n
Programmable Constant-Current Operation with
The LT3840’s low quiescent current, when configured for
Current Monitor Output
user selectable Burst Mode operation, helps extend run n
Low IQ: 75µA, 12VIN to 3.3VOUT
time in battery-powered systems by increasing efficiency n
Selectable Low Output Ripple Burst Mode®
at light loads. The LT3840 uses a constant frequency,
Operation
current mode architecture. High current applications are n VOUT Up to 60V possible with large N-channel gate drivers capable of n Adjustable and Synchronizable: 50kHz to 1MHz driving multiple low R n DS(ON) MOSFETs. Internal OVLO Protects for Input Transients Up to 80V n Accurate Input Overvoltage and Undervoltage Threshold An integrated buck-boost switching regulator generates n Programmable Soft-Start with Voltage Tracking a 7.5V bias supply voltage for MOSFET gate drive and IC n Power Good and Output OVP power allowing higher efficiency operation over the entire n 28-Lead TSSOP and 38-Lead 4mm × 6mm QFN Packages input voltage range and eliminating the need for an external bias voltage. An accurate current limit set point regulates
applicaTions
the maximum output current. A current monitor reports the average output current. n Automotive Supplies L, LT, LTC, LTM, Linear Technology, Burst Mode, and the Linear logo are registered n Industrial Systems trademarks of Linear Technology Corporation. All other trademarks are the property of their n respective owners. Distributed DC Power Systems
Typical applicaTion High Efficiency Synchronous Step-Down Converter
V
12V
IN
IN to 3.3VOUT Efficiency
4V TO 60V 68µF 1µF 33µH 100 ×2 95 AUXBST AUXSW1 AUXSW2 90 EN INTVCC 85 4.7µF VIN 80 75 AUXVIN BOOST LT3840 70 UVLO 1µF EFFICIENCY (%) 65 OVLO TG 1.5µH 2m VOUT 60 PG SW 3.3V 55 20A SYNC BG 330µF 50 0 5 10 15 20 ×2 MODE LOAD CURRENT (A) 3840 TA01b RT SENSE+ VC SENSE– 49.9k 20k 16.9k TK/SS FB 1500pF 100pF GND 10k IMON ICOMP ICTRL 2200pF 7.68k 3840 TA01a 470pF 3840fa For more information www.linear.com/LT3840 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts