Datasheet LT8614 (Analog Devices)

LT8614 42V, 4A Synchronous Step-Down Silent Switcher with 2.5µA Quiescent Current
FeaTures DescripTion
n
Silent Switcher
®
Architecture
The LT®8614 step-down regulator features Silent Switcher n
Ultralow EMI/EMC Emissions
architecture designed to minimize EMI/EMC emissions n
High Efficiency at High Frequency
while delivering high efficiency at frequencies up to 3MHz. n
Up to 96% Efficiency at 1MHz, 12VIN to 5VOUT
Assembled in a 3mm × 4mm QFN, the monolithic con- n
Up to 94% Efficiency at 2MHz, 12VIN to 5VOUT
struction with integrated power switches and inclusion of n
Wide Input Voltage Range: 3.4V to 42V
al necessary circuitry yields a solution with a minimal PCB n
Ultralow Quiescent Current Burst Mode® Operation:
footprint. An ultralow 2.5µA quiescent current—with the n
2.5μA IQ Regulating 12VIN to 3.3VOUT
output in full regulation— enables applications requiring n
Output Ripple < 10mVP-P
highest efficiency at very small load currents. Transient n
Fast Minimum Switch On-Time: 30ns
response remains excellent and output voltage ripple is n
Low Dropout Under All Conditions: 125mV at 1A
below 10mVP-P at any load, from zero to full current. n
Safely Tolerates Inductor Saturation in Overload
The LT8614 allows high VIN to low VOUT conversion at high n Adjustable and Synchronizable: 200kHz to 3MHz frequency with a fast minimum top switch on-time of 30ns. n Peak Current Mode Operation Operation is safe in overload even with a saturated inductor. n Accurate 1V Enable Pin Threshold n Internal Compensation Essential features are included and easy to use: An open- n Output Soft-Start and Tracking drain PG pin signals when the output is in regulation. The n Small 18-Lead 3mm × 4mm QFN SYNC pin allows clock synchronization and choice of Burst Mode operation or pulse-skipping mode. Soft-start and tracking functionality is accessed via the TR/SS pin. An
applicaTions
accurate enable threshold can be set using the EN/UV pin n and a resistor at the RT pin programs switch frequency. Automotive and Industrial Supplies n General Purpose Step-Down L, LT, LTC, LTM, Linear Technology, the Linear logo, Silent Switcher and Burst Mode are registered trademarks and Silent Switcher is a trademark of Analog Devices, Inc. All other n GSM Power Supplies trademarks are the property of their respective owners. Protected by U.S. patents, including 8823345.
Typical applicaTion 12VIN to 5VOUT Efficiency 5V 4A Step-Down Converter
100 1MHz 95 VIN 2MHz 5.8V TO 42V 90 4.7µF EN/UV VIN1 VIN2 1µF 1µF 85 GND1 GND2 80 LT8614 PG BST 0.1µF 4.7µH VOUT 10nF EFFICIENCY (%) 75 SYNC/MODE SW 5V TR/SS BIAS 4A 70 1µF 4.7pF 1M 65 INTVCC FB 47µF 41.2k 60 RT GND 243k 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 LOAD CURRENT (A) 8614 TA01b fSW = 1MHz 8614 TA01a 8614fd For more information www.linear.com/LT8614 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Applications Related Parts