Datasheet LT3757, LT3757A (Analog Devices)

LT3757/LT3757A Boost, Flyback, SEPIC and Inverting Controller
FEATURES DESCRIPTION
n
Wide Input Voltage Range: 2.9V to 40V
The LT®3757/LT3757A are wide input range, current n
Positive or Negative Output Voltage Programming
mode, DC/DC controllers which are capable of generating
with a Single Feedback Pin
either positive or negative output voltages. They can be n Current Mode Control Provides Excellent Transient configured as either a boost, flyback, SEPIC or inverting Response converter. The LT3757/LT3757A drive a low side external n Programmable Operating Frequency (100kHz to N-channel power MOSFET from an internal regulated 7.2V 1MHz) with One External Resistor supply. The fixed frequency, current-mode architecture n Synchronizable to an External Clock results in stable operation over a wide range of supply n Low Shutdown Current < 1µA and output voltages. n Internal 7.2V Low Dropout Voltage Regulator The operating frequency of LT3757/LT3757A can be set n Programmable Input Undervoltage Lockout with with an external resistor over a 100kHz to 1MHz range, Hysteresis and can be synchronized to an external clock using the n Programmable Soft-Start SYNC pin. A low minimum operating supply voltage of n Small 10-Lead DFN (3mm × 3mm) and Thermally 2.9V, and a low shutdown quiescent current of less than Enhanced 10-Pin MSOP Packages 1µA, make the LT3757/LT3757A ideally suited for battery- operated systems.
APPLICATIONS
The LT3757/LT3757A feature soft-start and frequency n Automotive and Industrial Boost, Flyback, SEPIC and foldback functions to limit inductor current during start- Inverting Converters up and output short-circuit. The LT3757A has improved n Telecom Power Supplies load transient performance compared to the LT3757. n Portable Electronic Equipment All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION High Efficiency Boost Converter Efficiency
VIN 8V TO 16V 100 10µF 200k V 25V IN 90 X5R 10µH SHDN/UVLO V V OUT IN = 8V 24V 80 43.2k LT3757 2A VIN = 16V SYNC GATE 226k 70 SENSE RT 60 SS FBX + 47µF EFFICIENCY (%) 35V V GND INTV 50 C CC ×2 41.2k 300kHz 16.2k 22k 40 4.7µF 10µF 0.1µF 10V 0.01Ω 25V 6.8nF X5R X5R 300.001 0.01 0.1 1 10 OUTPUT CURRENT (A) 3757 TA01b 3757 TA01a Rev. F Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Applications Information Typical Applications Package Description Revision History Typical Application Related Parts