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Reference Design
LM46001
SNVSA46B – JUNE 2014 – REVISED JANUARY 2018
LM46001 3.5-V to 60-V, 1-A Synchronous Step-Down Voltage Converter
1 Features
•1 24-µA Quiescent Current in Regulation • High Efficiency at Light Load (DCM and PFM) • Meets EN55022/CISPR 22 EMI standards • Integrated Synchronous Rectification • Adjustable Switching Frequency: 200 kHz to
2.2 MHz (500 kHz default) • Frequency Synchronization to External Clock • Internal Compensation • Stable With Many Combinations of Ceramic,
Polymer, Tantalum, and Aluminum Capacitors • Power-Good Flag • Soft Start into Pre-Biased Load • Internal Soft Start: 4.1 ms • Extendable Soft-Start Time by External Capacitor • Output Voltage Tracking Capability • Precision Enable to Program System UVLO • Output Short-Circuit Protection With Hiccup Mode • Overtemperature Thermal Shutdown Protection • Create a Custom Design Using the LM46001 With
the WEBENCH® Power Designer
2 Applications
• Industrial Power Supplies • Telecommunications Systems • Sub-AM Band 12-V and 24-V Automotive • Commercial Vehicle Power Supplies • General Purpose Wide VIN Regulation • High Efficiency Point-Of-Load Regulation
VIN CIN
Simplified Schematic
VIN SW LM46001
ENABLE PGOOD SS/TRK RT SYNC
AGND
CBOOT BIAS
FB VCC PGND
L CBOOT
COUT
VOUT
CBIAS
CFF
RFBT
CVCC
RFBB
3 Description
The LM46001 regulator is an easy-to-use synchronous step-down DC-DC converter capable of driving up to 1 A of load current from an input voltage ranging from 3.5 V to 60 V. The LM46001 provides exceptional efficiency, output accuracy, and dropout voltage in a very small solution size. An extended family is available in 0.5-A and 2-A load current options in pin-to-pin compatible packages. Peakcurrent-mode control is employed to achieve simple control loop compensation and cycle-by-cycle current limiting. Optional features such as programmable switching frequency, synchronization, power-good flag, precision enable, internal soft start, extendable soft start, and tracking provide a flexible and easy-touse platform for a wide range of applications. Discontinuous conduction and automatic frequency reduction at light loads improve light-load efficiency. The family requires few external components and pin arrangement allows simple, optimum PCB layout. Protection features include thermal shutdown, VCC undervoltage lockout, cycle-by-cycle current limit, and output short-circuit protection. The LM46001 device is available in the 16-lead HTSSOP package (PWP, 6.6 mm × 5.1 mm × 1.2 mm) with 0.65-mm lead pitch. The device is pin-to-pin compatible with LM46000, LM46002, LM43603, LM43602, LM43601, and LM43600.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
LM46001
HTSSOP (16)
6.60 mm × 5.10 mm
(1) For all available packages, see the orderable addendum at the end of the datasheet.
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Radiated Emission Graph VOUT = 3.3 V, VIN = 24 V, FS= 500 kHz, IOUT = 1 A
dBuV 80 70 60 50 40 30 20 10
30
Vertical Polarization Horizontal Polarization
EN 55022 Class B Limit
Evaluation Board Emissions
100 Frequency (MHz)
1000
Copyright © 2018, Texas Instruments Incorporated
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA.
LM46001
SNVSA46B – JUNE 2014 – REVISED JANUARY 2018
www.ti.com
Table of Contents
1 Features .................................................................. 1 2 Applications ........................................................... 1 3 Description ............................................................. 1 4 Revision History..................................................... 2 5 Pin Configuration and Functions ......................... 3 6 Specifications......................................................... 4
6.1 Absolute Maximum Ratings ...................................... 4 6.2 ESD Ratings.............................................................. 4 6.3 Recommended Operating Conditions....................... 4 6.4 Thermal Information .................................................. 5 6.5 Electrical Characteristics........................................... 5 6.6 Timing Requirements ................................................ 6 6.7 Switching Characteristics .......................................... 7 6.8 Typical Characteristics .............................................. 8 7 Detailed Description ............................................ 14 7.1 Overview ................................................................. 14 7.2 Functional Block Diagram ....................................... 14
7.3 Feature Description................................................. 15 7.4 Device Functional Modes........................................ 24 8 App.