Datasheet LT8611 (Analog Devices)

LT8611 42V, 2.5A Synchronous Step-Down Regulator with Current Sense and 2.5µA Quiescent Current
FEATURES DESCRIPTION
n
Rail-to-Rail Current Sense Amplifier with Monitor
The LT®8611 is a compact, high efficiency, high speed n
Wide Input Voltage Range: 3.4V to 42V
synchronous monolithic step-down switching regulator n
Ultralow Quiescent Current Burst Mode
®
Operation:
that consumes only 2.5µA of quiescent current. Top and n
2.5μA IQ Regulating 12VIN to 3.3VOUT
bottom power switches are included with all necessary n
Output Ripple < 10mVP-P
circuitry to minimize the need for external components. n
High Efficiency Synchronous Operation:
The built-in current sense amplifier with monitor and n
96% Efficiency at 1A, 5VOUT from 12VIN
control pins allows accurate input or output current n
94% Efficiency at 1A, 3.3VOUT from 12VIN
regulation and limiting. Low ripple Burst Mode operation n
Fast Minimum Switch-On Time: 50ns
enables high efficiency down to very low output currents n
Low Dropout Under All Conditions: 200mV at 1A
while keeping the output ripple below 10mVP-P. A SYNC n
Allows Use of Small Inductors
pin allows synchronization to an external clock. Internal n Low EMI compensation with peak current mode topology allows n Adjustable and Synchronizable: 200kHz to 2.2MHz the use of small inductors and results in fast transient n Current Mode Operation response and good loop stability. The EN/UV pin has an n Accurate 1V Enable Pin Threshold accurate 1V threshold and can be used to program VIN n Internal Compensation undervoltage lockout or to shut down the LT8611 reduc- n Output Soft-Start and Tracking ing the input supply current to 1µA. A capacitor on the n Small Thermally Enhanced 3mm × 5mm 24-Lead TR/SS pin programs the output voltage ramp rate during QFN Package start-up. The PG flag signals when VOUT is within ±9% of the programmed output voltage as wel as fault conditions.
APPLICATIONS
The LT8611 is available in a small 24-lead 3mm × 5mm n QFN package with exposed pad for low thermal resistance. Automotive and Industrial Supplies n General Purpose Step-Down L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective n CCCV Power Supplies owners.
TYPICAL APPLICATION 12V 5V Step-Down Converter with 2.5A Output Current Limit IN to 5VOUT Efficiency
100 VIN VIN BST 5.5V TO 42V 95 4.7µF ON OFF EN/UV 0.1µF 90 4.7µH 0.02Ω V SYNC OUT SW 85 LT8611 5V IMON 1µF 2.5A 80 ICTRL ISP 75 ISN 70 BIAS EFFICIENCY (%) 65 PG 10pF INTVCC 60 fSW = 700kHz TR/SS VIN = 12V 0.1µF 1M 55 V RT FB IN = 24V PGND GND 50 1µF 60.4k 243k 47µF 0 0.5 1 1.5 2 2.5 LOAD CURRENT (A) 8611 TA01a fSW = 700kHz 8611 G01 8611fa For more information www.linear.com/LT8611 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts