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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current

LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current
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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current - 1

LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3µA Quiescent Current Description Features Rail-to-Rail Current Sense Amplifier with Monitor n Wide Input Voltage Range: 3.4V to 42V n Ultralow Quiescent Current Burst Mode® Operation: 3μA IQ Regulating 12VIN to 3.3VOUT Output Ripple < 10mVP-P n High Efficiency Synchronous Operation: 95% Efficiency at 3A, 5VOUT from 12VIN 94% Efficiency at 3A, 3.3VOUT from 12VIN n Fast Minimum Switch-On Time: 40ns n Low Dropout Under All Conditions: 250mV at 3A n Allows Use Of Small Inductors n Low EMI n Adjustable and Synchronizable: 200kHz to 2.2MHz n Current Mode Operation n Accurate 1V Enable Pin Threshold n Internal Compensation n Output Soft-Start and Tracking n Small Thermally Enhanced 3mm × 6mm 28-Lead QFN Package n Applications Automotive and Industrial Supplies General Purpose Step-Down n CCCV Power Supplies n The LT®8613 is a compact, high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 3µA of quiescent current. Top and bottom power switches are included with all necessary circuitry to minimize the need for external components. The built-in current sense amplifier with monitor and control pins allows accurate input or output current regulation and limiting. Low ripple Burst Mode operation enables high efficiency down to very low output currents while keeping the output ripple below 10mVP-P. A SYNC pin allows synchronization to an external clock. Internal compensation with peak current mode topology allows the use of small inductors and results in fast transient response and good loop stability. The EN/UV pin has an accurate 1V threshold and can be used to program VIN undervoltage lockout or to shut down the LT8613 reducing the input supply current to 1µA. A capacitor on the TR/SS pin programs the output voltage ramp rate during start-up. The PG flag signals when VOUT is within ±9% of the programmed output voltage as well as fault conditions. The LT8613 is available in a small 28-lead 3mm × 6mm QFN package with exposed pad for low thermal resistance. 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 owners. Typical Application 5V Step-Down Converter with 6A Output Current Limit 10µF ON OFF EN/UV SYNC IMON BIAS INTVCC

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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current - 2

Absolute Maximum Ratings UDE PACKAGE 28-LEAD (3mm × 6mm) PLASTIC QFN θJA = 40°C/W, θJC(PAD) = 5°C/W EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB Order Information LEAD FREE FINISH PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and...

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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current - 3

The • denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device Note 2: The LT8613E is guaranteed to meet performance specifications from 0°C to 125°C junction temperature. Specifications over the -40°C to 125°C operating junction temperature range are assured by design, characterization, and correlation with statistical process...

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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current - 4

LT8613 Typical Performance Characteristics Efficiency at 3.3VOUT LOAD REGULATION (%) EN/UV RISING EN/UV FALLING Load Regulation

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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current - 5

LT8613 Typical Performance Characteristics No Load Supply Current Top FET Current Limit vs Duty Cycle Minimum Load to Full Frequency (SYNC Hi) Burst Frequency Switching Frequency Dropout Voltage Minimum Off-Time Minimum On-Time

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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current - 6

LT8613 Typical Performance Characteristics Frequency Foldback VOUT = 3.3V VIN = 12V VSYNC = 0V RT = 60.4k Soft-Start Current RT Programmed Switching Frequency Switching Waveforms Switching Waveforms PG THRESHOLD OFFSET FROM VREF (%) PG THRESHOLD OFFSET FROM VREF (%) 12VIN TO 5VOUT AT 20mA; FRONT PAGE APP VSYNC = 0V

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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current - 7

LT8613 Typical Performance Characteristics Switching Waveforms Transient Response Transient Response Start-Up Dropout Performance 1A TO 3A TRANSIENT 12VIN TO 5VOUT COUT = 2×47µF FRONT PAGE APP Start-Up Dropout Performance 1A TO 2A TRANSIENT 12VIN TO 5VOUT COUT = 2×47µF FRONT PAGE APP 0.1A TO 1.1A TRANSIENT 12VIN TO 5VOUT COUT = 2×47µF FRONT PAGE APP Transient Response

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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current - 8

LT8613 Typical Performance Characteristics ICTRL Voltage VISP-VISN Sense Voltage VISP-VISN Sense Voltage IMON Voltage

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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current - 9

LT8613 Pin Functions SYNC (Pin 1): External Clock Synchronization Input. Ground this pin for low ripple Burst Mode operation at low output loads. Tie to a clock source for synchronization to an external frequency. Apply a DC voltage of 3V or higher or tie to INTVCC for pulse-skipping mode. When in pulseskipping mode, the IQ will increase to several hundred µA. When SYNC is DC high or synchronized, frequency foldback will be disabled. Do not float this pin. GND (Pins 11, 12, 13, 14): It is recommended that these be connected to GND so that the exposed pad GND can be run to the top level GND...

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LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3?A Quiescent Current - 10

LT8613 Pin Functions ISN (Pin 26): Current Sense (–) Pin. This is the inverting input to the current sense amplifier. IMON (Pin 27): Proportional-to-Current Monitor Output. This pin sources a voltage 20 times the voltage between the ISP and ISN pins such that: VIMON = 20 • (VISP-VISN). IMON can source 200µA and sink 10µA. Float IMON if unused. ICTRL (Pin 28): Current Adjustment Pin. ICTRL adjusts the maximum ISP-ISN drop before the LT8613 reduces output current. Connect directly to INTVCC or float for full-scale ISP-ISN threshold of 50mV or apply values between GND and 1V to modulate...

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